Oils, cavitation and viscosity

quote:

Originally posted by Aus Ford:
Given the 351c oil system cavitation issues would it not be benificial to use a oil with a viscosity toward the thinner end of the recommend ie: 10w40 rather than 20w50 ?

What are the thoughts out there about synthetic oils and their cavitation resistance ?

This is the first that I've heard about a cavitation issue.

The 20-50 recommendation came about as a Ford recommendation for the production Boss 351.

To me a 20 weight winter grade has always been questionable. I would take a guess and say that what the engineers wanted was the 50 weight and the only way available back then in multigrade was the 20-50.

Personally I feel with the availability of relatively inexpensive full synthetic like Mobil1, a 10-30 or 10-40 is fine for even racing use in this engine.


Oil weight really is going to be determined by the clearances that the engine has on the main bearings. The greater the clearances the thicker the viscosity of the oil needs to be.

I would think if you maintain 1.5 thousands clearances on those bearings a standard weight oil would be fine?


I never heard of the C oil pump having cavitation, or sucking air, at any rpm. These engines have been raced hard since the beginning of their introduction and the significant oiling modification for sustain high rpm is to restrict oil through the lifter galleries.

The designs of the Cleveland oil pumps is no different than any other engine. for racing purposes it is recommended to braze the oil pickup tube to the oil pump body but that's just to keep the tube from vibrating loose.

Another issue with racing them in NASCAR that was attributed to oiling issues was valve spring failure.

That was corrected in changing the oil drain back rate in the cylinder head. What was needed was to bathe the valve springs in oil to cool them to prevent failure.

You need to maintain about 1.5 to 2 inches of oil in the valve cover to cover the valve springs for cooling purposes FOR ENDURANCE TYPE RACING. Street cars do not need this.

That was done on the racing heads by changing the drain back holes in the heads. Also using the Ford Boss 302 drain back hose modification to the valve covers would be the opposite of what you want in a racing Cleveland.

I do not know if the T/A Boss 302's had this issue at all.

I've been using Amsoil & Bel Ray synthetic oils in my motorcycles since the 1980s with great success. I've used Mobil 1 synthetic oils in my cars since the early 1990s, also with great success. I'm not aware that synthetic oils resist cavitation any better however.

10W oils are good for use in a Cleveland set-up with standard type bearing clearances. As are 15W and 20W oils. Standard main bearing clearances for street performance being 0.0020” to 0.0025” and standard rod bearing clearances being 0.0025” to 0.0030”. The guys I know using 10W oil in their race engines use 10W30, not 10W40. The 10W viscosities may resist cavitation a little better than 15W or 20W, but enough to make a difference? I can't say. What the thinner viscosities will do a little better is make the sharp 90 degree turn off the main oil passage into the branches which feed the center 3 main bearings. Therefore they flow a little more oil to the rod bearings, and keep the bearings a little cooler.

FYI Ford's original recommendation for the 351C here in the states was 20W40. But 20W40 didn't stay on the shelves long, by the late 1970s it was replaced by 20W50. 20W50 was the standard for several decades. In the last decade I've seen 10W30 become more popular while 20W50 has fallen out of popularity.

You shouldn't use thinner oil (0W or 5W) unless the main & rod bearings clearances are set-up tighter and more precisely for the thinner oils. If the bearings are set-up tight, then consider synthetic oil a necessity, because the bearing temperatures run hotter. Also, if you're using the thinner oils (0W or 5W) don't use fully groove main bearings either, use 3/4 groove main bearings instead. Finally, since the 0W and 5W oils will tend to squirt more easily out all the unproductive clearances; tappet bore bushings become more of a necessity with those ultra-low viscosity oils.

-G

A point of clarification, the "W" part of the viscosity grade designation indicates cold temperature performance only. The second number is the operating temperature (210*F) viscosity. A 5W-50 is the exact same oil as a 20W-50 at operating temperature, however the 5W-X will flow a lot better cold - not a bad thing, but unnecessary for mild temperatures like So-Cal or summer anywhere else.

The #1 benefit of synthetics is they do not oxidize as readily as conventional oil, and that keeps your motor clean of deposits. The #2 benefit is they naturally have a broader viscosity index. That means they can be formulated with less viscosity improving additives, that eventually shear down over time.

I think that with full synthetic and natural oil, we are really talking about two different animals.

Full synthetic flows much better than natural does at low temps and maintains viscosity much better at high temps.

It doesn't break down viscosity wise the same as natural does.

To compare the two is really talking apples and oranges with an engineering "interpreter" in between trying to translate.

The 20-50 was done at a time when essentially only natural oils were available.

There were variations in that such as full Pennsylvania grade like Penn State. To me that was the absolute best of any natural oil ever marketed to the general public.

It no longer exists as full Pennsylvania grade and now is just a blend.

The other was mineral oil which I don't know much about other than it is not compatable with the other oils.

I like Mobil1 full synthetic. It has been run in race cars for around 40 years now and has shown nothing but superior characteristics at every scientific comparison.

The "ice truckers" have different issues that even full synthetic doesn't solve but unless you are constantly running well below zero Farenheit Mobil1 will do you fine.

When you rebuild you want to maintain about 1.5 thousands clearance on your bearings. If you do, even 10-30 is fine.

It has to do with film strength of the oil.

Mobil1 likes to say that it just isn't oil, it's "liquid engineering". I can't say as I argue with that.

I think also that if your engine is having issues with wet sump oil cavitation then you should be running a dry sump system.

If that doesn't work for you, take up a different hobby altogether like hot air ballooning? There is no engine oil involved in that at all?

quote:

Originally posted by PanteraDoug:


This is the first that I've heard about a cavitation issue.



I never heard of the C oil pump having cavitation, or sucking air, at any rpm. These engines have been raced hard since the beginning of their introduction and the significant oiling modification for sustain high rpm is to restrict oil through the lifter galleries.

The designs of the Cleveland oil pumps is no different than any other engine. for racing purposes it is recommended to braze the oil pickup tube to the oil pump body but that's just to keep the tube from vibrating loose.

I was referring to some things mentioned in Sticky 3:

Quote from sticky 3:
The diagnosis of this problem which I find most compelling is based on hydraulic system engineering; Roy Johnson suggests the problem is cavitation which occurs first at the oil pump. Jon Kaase has commented “what the 351C needs is not a high volume oil pump but a standard oil pump with dual inlets”.

Johnson has further suggested cavitation manifests again in the main lubrication passages resulting in a sag in oil pressure in the middle of each passage as engine speed increases.

The large ports connecting each tappet bore to one of the two oil passages expose the motion of the tappets to the oil passages.

Jim Kuntz has commented on the detrimental effect of the "lifters chopping up and down in the main oil supply". Thus cavitation resulting from the rapid motion of the tappets spreads to the oil passages through these ports.

As the clearance between the tappets and the tappet bores increases so does the severity of cavitation. So as a motor gets older the lubrication system cavitates worse.


Has anyone seen a pump with dual inlets for the 351c ?


I do some work with hydraulics myself and i often thought that the 351c may have some cavitation issues effecting lubrication quality.

Industral hydraulic pumps with smaller volume than the 351c pump would have larger inlets, maybe 1" or 1 1/4"NPT and they spin more slowly than a 351c pump, maybe only 1440rpm, so if the 351c pump doesn't cavitate at all that pump would be pretty outstanding.

I've had 351c and 302c engines in cars that have been well maintained, oil changes done on time or even early with top quality oils and filters used, never left with low oil level and have not been driven hard and on teardown had all the bearings worn down to the base metal.

I do feel there is more to the subject than just straight common sense may suggest....??

A interesting animation of cavitation inside a gerotor pump.



Gerotors usually require the depth of the inlet ports to be at least the same as the width of the gerotor.

The ports in the 351c pump are less than that.

I think the opinion given in Sticky 3 about the 351c pump needing two inlets is correct.

The wide 351c gerotor needs to be fed oil from both sides instead of just one.

This animation shows a deep inlet port below the gerotor and a narrow "shadow port" above. Note the constant cavitation in the shadow port and cavitation in almost 3/4 of the gerotor.

quote:

351c pump needing two inlets is correct.

Or the 10 quart oil pan with the proper pick up and baffles in the pan probably accomplish the same thing ... one thing for sure if you have 2 pickups ( inlets ) and one runs dry ... you still have the pump sucking air ... and the second will surely not suck oil from the pan. So not sure what the basis of two inlet would accomplish ? Temperature and vaporizing are a major contributing factor. So maybe an oil cooler would help.

[/QUOTE]Or the 10 quart oil pan with the proper pick up and baffles in the pan probably accomplish the same thing ..[/QUOTE]


If cavitation is taking place 44 gallons of oil will not help, boat propellers cavitate and they are in an entire ocean of water. Also Maybe not everyone can fit a larger pan, i wish i could fit a 10 quart pan in my car.



[/QUOTE]one thing for sure if you have 2 pickups ( inlets ) and one runs dry ... you still have the pump sucking air ... and the second will surely not suck oil from the pan.[/QUOTE]

True.....the two pick up tubes would need to come together to the same pickup point and be connected to the same pickup.


[/QUOTE] So not sure what the basis of two inlet would accomplish ? Temperature and vaporizing are a major contributing factor. So maybe an oil cooler would help.[/QUOTE]


Two inlets would slow the velocity of the incoming oil by 50 percent and could feed the gerotor from both sides instead of just one side. Single inlet gerotors are more prone to cavitation.

Yes an oil cooler is always a good thing !

quote:

If cavitation is taking place 44 gallons of oil will not help, boat propellers cavitate and they are in an entire ocean of water. Also Maybe not everyone can fit a larger pan, i wish i could fit a 10 quart pan in my car.

There are two companies that make a high capacity 10 qt pan for the Pantera.


The screen in the pickup is not only to screen out debris but to remove air bubbles from the incoming oil ... which could be generated by overhead oil / vaporizing. The larger 10 quart oil pan MADE for the Pantera doubles the capacity of the oil and displacing more surface area with the potential of cooler oil and since its in fact a closed system and not the entire ocean ... cavitation can be prevented.
I think the Competition Cars pretty much have it sorted out ... no reason to reinvent the wheel.

If you don't have a Pantera, there are also 9 quart pans made in the T configuration to fit Mustangs and other cars made by Canton, Aviaid, and Armondo that virtually eliminate cavitation.

There is a Chevy, Camaro/Corvette Aviaid pan. It has one advantage. It has a swing pickup and the pickup moves with the g-forces generated. It is Chevy only. Fords don't need it.

Cars that still have issues need to go to a drysump system.

I'm in with the Aviaid in the Pantera and a Canton road race pan on my Shelby.

Personally I worry about messing up the finish on the pans, not cavitation.

This isn't even worthy of mention in "Conspiracy Theory". I don't loose sleep over it.

quote:

Personally I worry about messing up the finish on the pans, not cavitation.

LOL ... exactly.

I'm sorry but i feel we are not reading from the same prayer book.

quote:

Originally posted by accobra:
The screen in the pickup is not only to screen out debris but to remove air bubbles from the incoming oil ... which could be generated by overhead oil / vaporizing.

Cavitation is NOT air bubbles in the incoming oil.

Cavitation should not be confused with Aeration.

Cavitation is the inability of the oil to flow into the pump at a rate equal to that at which the oil is being pumped out.

It is a phenomenon that takes place internally inside the pump, if it is taking place no amount of oil in the sump or sump design will have any influence over it.

It is essentially a cavity, a void in the oil, it does not consist of air but rather vacuum. In liquids with low boiling points and high vapor pressures it can contain that liquid in vaporised form.

Motor oil will smoke and catch fire usually before it reaches boiling (more than 300 degrees) so it's vapor pressure even when hot is such that it's viscosity is more of a influence on cavitation.

Cooling the oil will in fact make it worse as the oil at higher viscosity will be more resistant to flowing into the pump and through the pump's ports.

It cannot be observed externally (unless you had a pump and engine made of glass) and it decreases the efficiency of the pump especially as the pump speed increases.

Also increasing the pump size (high volume pump) will make it worse not better. Possibly the reason why many oppose the use of high volume pumps.




I couldn't give two hoots about the finish on the pan.

Cavitation occurs when a moving mechanical part moves so quickly that the fluid which it is contact with cannot keep up. Since the fluid cannot move as quickly as the mechanical part, it sheers away from the moving part, creating a void. Cavitation is most likely to occur when there is a relatively large clearance between a moving part and a stationary part, or a large clearance between two moving parts. Tight clearances serve to inhibit the creation of voids.

The results of cavitation manifest in many ways. A cavitating water pump will produce a noise that sounds like marbles banging around inside the pump. Cavitation will erode the impeller of a pump. And cavitation will double the amount of energy required to rotate a pump. Cavitation will occur at the interface between a turning crankshaft and the bearings that support the shaft, bearing erosion will occur as a result. Cavitation is not limited to rotating parts either. Cavitation can take place with parts having linear motion too, as in the case of the 351C tappets. The large port in the wall of each tappet bore provides the clearance needed for the oil to sheer away from the tappet as it moves up and down within the bore.

On the subject of oil pumps, I can show you Ford literature from the 1960s recommending 3/4" ID for the oil pump suction line of a high performance motor, yet the largest suction line you can screw into a 351C oil pump has an ID of 5/8". As Homer Simpson would say ... DOH!

There are several reasons for not using a high volume pump in the 351C. First of all, it is seldom mentioned, but the 351C was equipped with a high volume pump from the factory. The volume of the 351C oil pump is quite a bit higher than the oil pump in Ford's other engines. Second, the additional volume of a high volume oil pump is just going to squirt more oil through the non-productive clearances unless something is done to prevent it (tappet bore bushings). And if you do something to prevent oil being wasted in the non-productive clearances you'll find you no longer need the extra capacity of the high volume pump. Third, a high volume oil pump may pump more oil to the valve train, or pump oil to the valve train at a higher rate, thereby emptying the oil pan more quickly. Fourth, a high volume oil pump may sling more oil from the bearing clearances, loading the cylinder walls with more oil and overwhelming the oil rings ability to scrape oil off the cylinder walls. Fifth, as you've already mentioned, since the size of the suction line remains unchanged, a high volume oil pump will cavitate worse than the standard pump. Sixth, a pump can only push a certain amount of oil through the passages in the 351C block at any given pressure, to increase the flow of oil the pressure must be increased, but if a high volume pump has the same oil pressure spring as the standard pump it will not increase oil flow, it will simply recirculate the additional oil back to the pump inlet. So what happens, the high volume pump pumps more oil through the motor at low rpm, but once the oil pressure reaches the setting of the spring, then the amount of oil delivered to the block will be the same. As a result there's no change in oil flow at higher rpm.

quote:

Originally posted by Aus Ford:

I couldn't give two hoots about the finish on the pan.

You are missing the point. The finish on the pan is at least twice as important as this cavitation issue, and the finish isn't very important at all.

This engine has been run in production and competition for over 40 years. This issue has yet to manifest itself.

quote:

Originally posted by PanteraDoug:

You are missing the point. The finish on the pan is at least twice as important as this cavitation issue, and the finish isn't very important at all.

This engine has been run in production and competition for over 40 years. This issue has yet to manifest itself.

That's cool. To each their own.

quote:

Originally posted by PanteraDoug:

... cavitation ... This issue has yet to manifest itself.

An intelligent & professional practitioner of the hot rodding arts, who is also a hydraulic engineer from the aviation industry, claims cavitation and leakage have been the issues with the 351C lubrication system all along. Others have intuitively hinted at the issue without labeling the problem as cavitation. I found the diagnosis compelling, so I consulted a couple of hydraulic engineers I know from my career in industry; after looking into the situation they fully agreed with the diagnosis, as though it was rather matter of fact. One commented "of course the tappets are going to cavitate at high speed".

quote:

Originally posted by George P:

An intelligent & professional practitioner of the hot rodding arts, who is also a hydraulic engineer from the aviation industry, claims cavitation and leakage have been the issues with the 351C lubrication system all along. Others have intuitively hinted at the issue without labeling the problem as cavitation. I found the diagnosis compelling, so I consulted a couple of hydraulic engineers I know from my career in industry; after looking into the situation they fully agreed with the diagnosis, as though it was rather matter of fact. One commented "of course the tappets are going to cavitate at high speed".

I guess I don't read well anymore? I thought the issue was with oil pump cavitation? There's even a video illustrating it?

You wrote cavitation hadn't manifested itself as a problem with the 351C, you didn't really specify oil pump cavitation. I was focused on the issue of cavitation as a whole. I realize this may be new information to you Doug. Since lifter cavitation is the problem that most impacts the 351C I figured you'd be able to relate better if I used that as an example. If that muddies the issue for you I apologize. Yes cavitation is a problem at both the pump and the lifters.

quote:

Originally posted by George P:
On the subject of oil pumps, I can show you Ford literature from the 1960s recommending 3/4" ID for the oil pump suction line of a high performance motor, yet the largest suction line you can screw into a 351C oil pump has an ID of 5/8". As Homer Simpson would say ... DOH!

That's interesting information George.

It doesn't sound like much to go from 5/8" to 3/4" but that small change in size would actually result in almost 50 percent reduction in resistance to the inflowing oil. A considerable improvement to alleviate possible pump cavitation.

I do say possible cavitation because as i said earlier you can't see caviation unless you had xray vision, and it is hard to hear in a engine, the castings are too massive and the engine makes too much noise, you can only imagine it based on experience of what similar systems of similar design have been know to do in other circumstances. The experience of the hydraulic engineers is paramount.

I do agree with you that the lifter bore issue is a far worse problem than the oil pump and i think if a motor is being built up from scratch that is the way to go.

I was looking at this with the perspective of what can be done to a motor that is in a car and does not at this stage require a rebuild but could benefit from simple bolt on modifications eg: while the sump is off changing the stock connecting rod nuts perhaps look into the oil pump and sump for possible improvements ??

I agree a high volume pump is not desirable in the 351c and likely to make things worse.

But a larger inlet to any pump makes sense in any application whether it is a oil pump in a engine or a hydraulic pump or a fuel pump. Like the ports in the cylinder heads the inlet needs to be bigger than the exhaust/outlet.

Most things are made to a price or for ease of manufacture or simply designed to be "good enough" it is rare that no improvement can possibly be made to a item or system and subtle improvements are made to every other aspect of the 351c often without a moments thought. I don't understand why the oil pump should be thought of as "untouchable" especially when it is a bolt on item and easily changed out.



Best regards to everyone on the forum

quote:

Originally posted by George P:
You wrote cavitation hadn't manifested itself as a problem with the 351C, you didn't really specify oil pump cavitation. I was focused on the issue of cavitation as a whole. I realize this may be new information to you Doug. Since lifter cavitation is the problem that most impacts the 351C I figured you'd be able to relate better if I used that as an example. If that muddies the issue for you I apologize. Yes cavitation is a problem at both the pump and the lifters.

It isn't a muddied concept for me at all George.

The lifter bore sleeve is a modification for racing, i.e., over a certain rpm.

Cavatation of the oil pump, the same...over a certain rpm.

It is a free world and it is your web page.

You can discuss whatever esoteric issues you prefer on infanitum.

Maybe how many angels can sit on the head of a pin, Quasars being super massive black holes and how will that effect the corn crops, and most importantly our Sun is well past it's half life, has only three billion years left of life before it becomes a Red Giant, and where you are going to park the Pantera when that happens. That one keeps me up at night.

This one won't. Good day to you sirs.

quote:

Originally posted by PanteraDoug:


our Sun is well past it's half life, has only three billion years left of life before it becomes a Red Giant, and where you are going to park the Pantera when that happens. That one keeps me up at night.

I disagree, i think the sun has a good 5 billion years to go to the red giant stage.

Best regards.

quote:

Originally posted by Aus Ford:

quote:

Originally posted by PanteraDoug:


our Sun is well past it's half life, has only three billion years left of life before it becomes a Red Giant, and where you are going to park the Pantera when that happens. That one keeps me up at night.

I disagree, i think the sun has a good 5 billion years to go to the red giant stage.

Best regards.

How can you tell?

quote:

Originally posted by George P:

An intelligent & professional practitioner of the hot rodding arts, who is also a hydraulic engineer from the aviation industry, claims cavitation and leakage have been the issues with the 351C lubrication system all along. Others have intuitively hinted at the issue without labeling the problem as cavitation. I found the diagnosis compelling, so I consulted a couple of hydraulic engineers I know from my career in industry; after looking into the situation they fully agreed with the diagnosis, as though it was rather matter of fact. One commented "of course the tappets are going to cavitate at high speed".

So what is the solution George? You show a photo of sleeved lifter bores. Please explain what you have done here, why you did it and what the benefit is?

Thanks, I love learning how experts have solved these issues.

quote:

Originally posted by Coolvet:

So what is the solution George? You show a photo of sleeved lifter bores. Please explain what you have done here, why you did it and what the benefit is?

Thanks, I love learning how experts have solved these issues.

If i may be so bold as to answer on George's behalf, George please add to this or clarify it as you see fit.

The idea is :
the passage you can see in the lifter bore in the first pic, is in a 351c, the main oil gallery feeding oil to firstly the lifters but then the crankshaft main bearings and from there the connecting rod bearings.

You can see it is quite a large hole. The lifters don't really require the hole to be that large, a small hole only 1/16 of a inch would suffice to lubricate the lifters and the top end, but because of manufacturing reasons that gallery intersects with the lifter bores in such a way it produces the massive port you can see in every lifter bore.

This exposes the reciprocating motion of the lifters to the flow of oil going to the bearings. This lifter motion is tremendously fast and of course reverses in direction. This causes a phenomenon Known as Cavitation.

Cavitation is a void, a cavity in the oil consisting of vacuum or vaporised oil. This is not good to have going to your bearings !

This mostly is noticed at high speed above 7000rpm and is probably the cause of all those cleveland spun bearing stories i'm sure you have heard. I'm in Sydney too and i've heard a million.

The solution shown in picture two is to sleeve the lifter bores with bronze bushes with only a 1/16" hole for lifter/ top end oil, that way the oil flow does not get exposed to the extreme acceleration forces and motion of the lifters and hence cavitation is eliminated so the bearings get a uncompromised oil flow.

That's the theory of it anyway.

quote:

Originally posted by Aus Ford:

quote:

Originally posted by Coolvet:

So what is the solution George? You show a photo of sleeved lifter bores. Please explain what you have done here, why you did it and what the benefit is?

Thanks, I love learning how experts have solved these issues.

This mostly is noticed at high speed above 7000rpm and is probably the cause of all those cleveland spun bearing stories i'm sure you have heard. I'm in Sydney too and i've heard a million.

I'm in NY and have heard of zero. I go back quite a ways with cars and with these engines.

They were run in Pro Stock drag racing and NASCAR in the early 70s.

When you go racing, it is common sense that production based engines are going to show their weak spots at racing conditions and need modifications.

This does not mean they have inferior designs or have major oversights. Just means there are additional solutions required to extend their dependable operating ranges.

Virtually every US production based race engine has needed high speed durability improvements.

The Cleveland is no worse or better than the others.

Over oiling was identified by many virtually as soon as the engine became available and certainly apparent under race conditions.

Jack Rousche talked about it briefly in an article he wrote for Hot Rod Magazine in 1972. "Pro-fecting the 351c". This really is old news.

The necessity to supply adequate oil to pressurize hydraulic lifters is what created the over oiling situation for race cars that need extended durability. I suppose you could say that not offering two different blocks, one for hydraulic lifters and one for solids is or creates the issue?

The Cleveland and the 427 Ford have certain similarities in a sense. Both have such potential as an above 7,000 rpm race engine and yet both had issues above it.

The 427 block eventually wound up as having an additional external oiling gallery added to the casting in order to make it a priority oiler. That block has been nicknamed the side oiler.

I for one don't feel I need to be warned about going over 7,000 rpm with any of these engines. There in fact are many things that can fail then and if you go over and it breaks I'm sure I can find someone who will say, "see, I told you so".

Thank you for your caution on this anyway, even as a just in case you didnt know warning...

quote:

Originally posted by PanteraDoug:

quote:

Originally posted by Aus Ford:

quote:

Originally posted by Coolvet:

So what is the solution George? You show a photo of sleeved lifter bores. Please explain what you have done here, why you did it and what the benefit is?

Thanks, I love learning how experts have solved these issues.

This mostly is noticed at high speed above 7000rpm and is probably the cause of all those cleveland spun bearing stories i'm sure you have heard. I'm in Sydney too and i've heard a million.

I'm in NY and have heard of zero. I go back quite a ways with cars and with these engines.


Thank you for your caution on this anyway, even as a just in case you didnt know warning...

Not saying Sydney has any special geographical advantage over NY, it's just in AUS the 351c was about the most common big engine around for a long time, It was the biggest passenger car engine available for some 13 or 14 years, we had windsors for a short time but we never had 427s, 429s, 460s, Mel engines, chev 454s, chrysler wedge engines or any of the 1000 v8's commonly used in the US (only in the odd import), so most of the stories you would hear were about the 351c and i still hear and read about the 2 & 7 rod bearing thing.

Maybe we do all kinds of strange things with them here that in the US another engine would be chosen for ?? Who knows ??

I was just explaining the meaning of the pics in Georges post, it's up to each reader to judge if it is twaddle or not.



We should stick to the 3 billion/5 billion year sun issue, lol

quote:

Originally posted by Coolvet:

So what is the solution George? You show a photo of sleeved lifter bores. Please explain what you have done here, why you did it and what the benefit is?

Thanks, I love learning how experts have solved these issues.

AusFord did a good job of summing it up. The large ports on the side of each tappet bore give rise to cavitation and excessive oil leakage. The cavitation worsens as engine speed increases and eventually reaches a point where it inhibits the flow of oil to the central 3 main bearings. Oil leakage starves the lubrication system for sufficient oil to performs its task. The bushings resolve those problems ... and several others.

The performance of the lubrication system has always been an unavoidable subject when the topic is the 351C. Many show-room new motors could barely reach 50 psi hot oil pressure (when measured with an accurate gauge) yet most of us considered 50 psi hot oil pressure as “marginal” or “dismal”. Ford’s original spec for 351C hot oil pressure was 50 to 70 psi by 2000 rpm. So the prevailing opinion was something needed to be done to bring the hot oil pressure within spec when we were hot-rodding the stock motors. Dyno Don Nicholson was among those who advocated 60 psi hot oil pressure that holds steady until the rev-limit as enough pressure even for Pro-Stock racing. Seventy psi hot oil pressure was considered “excellent”, in fact some would call 70 psi “more than enough“ or “over-kill”. But Ford’s Pro Stock Pinto book also warned us to shut the motor off immediately if the hot oil pressure dropped below 50 psi at high rpm.

With very few modifications the Cleveland becomes a motor that invites the driver to rev it hard. One thing many of us discovered the hard way, the con-rod bearings would show signs of under-lubrication when the motor was run at high rpm, even if the hot oil pressure was 60 psi or more. High oil pressure alone did not reliably guarantee the rod bearings were receiving sufficient lubrication.

I must at least mention that limiting the amount of oil flowing to the valve train is essential when building a high performance 351C. When more oil flows to the valve train than what is needed to lubricate parts and cool the valve springs it is diverted from the main and rod bearings were its really needed. The 351C has always had tappet incompatibility issues as well. The wrong tappets will pass too much oil to the valve train, in some cases the oil pan will be pumped dry at higher rpm because the oil is pumped to the valve train faster than it can drain back.

I was doing a solid lifter motor for a guy about 1976; I went to my local Ford speed & machine shop to pick up some parts, including the high pressure oil pump spring so loved by Jack Roush. The guys at the speed shop told me that the spring (introduced in 1972) had fallen out of favor for solid lifter motors and the new hot tip was tappet bore bushings. Ford had begun selling a very expensive do-it-yourself kit for installing them at home about 1974. That was my first introduction to tappet bore bushings.

Since Ford had ceased printing the OHO Newsletter prior to the 1973 race season the word about the tappet bore bushings never got out to the public at large. In fact the Ford Performance book by Pat Ganahl, (published in 1979) quoted the 1972 Pro Stock Pinto book regarding the lubrication system, a quote which recommended the high pressure oil pump spring for solid lifter motors. Of course, boosting oil pressure with the spring (introduced in 1972 the same year the Pro Stock Pinto Book was published) didn't fix the lubrication system so racers continued looking for a solution. Tappet bore bushings came on the scene during the 1973 race season and became the ultimate solution. Ford began selling the tappet bore bushing installation kit about a year later. Unfortunately by quoting the Pro Stock Pinto book regarding the lubrication system Pat Ganahl's book perpetuated old (erroneous) information and has mislead 351C enthusiasts regarding the lubrication system for decades.

So the four modifications listed below became common for solid lifter motors to prevent rod-bearing under-lubrication, but only common for those who were aware of the tappet bore bushing solution:

(1) The main bearing and rod bearing clearances were increased.
(2) Clevite 77 bearings were installed, which included fully grooved main bearings.
(3) Cam bearing oil passage restrictions were installed
(4) Tappet bore bushings were installed using a self-piloting do-it-yourself kit sold under the table by Ford or via Ford’s contractors and various Ford engine shops.

Even though Ford’s bushing kit was very expensive it was considered an essential modification for solid tappet motors to prevent rod bearing damage. And although my opinion is different today, 40 years ago we didn’t feel the bushings were essential for hydraulic tappet street motors. There were three schools of thought regarding modifying the 351C lubrication system for hydraulic tappet street motors:

(1) One school of thought preferred no modifications at all. The guys who advocated this insisted the lubrication system and bearing clearances were good “as-is” up to 6000 rpm. Checking oil pressure with an accurate gauge however revealed that 351C’s could not achieve 60 psi hot oil pressure off the show room floor, most couldn't achieve 50 psi hot oil pressure. And the factory spec for the bearing clearances was very tight. So even though some guys insisted the short block was good "as-is" the rod bearings told a different story. When we pulled piston & rod assemblies we always found signs of rod bearing “harm”.

(2) A second school of thought preferred following the advice given by Jack Roush in a 1976 story published in Hot Rod magazine. Jack Roush recommended a standard volume oil pump, the Moroso high pressure oil pump relief spring and the Moroso cam bearing restriction kit used in conjunction with 0.0020" to 0.0025" main bearing clearance and 0.0025" to 0.0030" rod bearing clearance. The motor’s cold start oil pressure ran about 120 psi with the high pressure oil pump relief spring installed, enough to burst an oil filter canister if the driver inadvertently blipped the throttle when the oil was cold, as many guys found out the hard way. A Motorcraft high pressure oil filter # FL-1HP was needed if the high pressure spring was installed.

(3) The final school of thought preferred a high volume oil pump to deliver more oil to the rod bearings which had the clearances increased to 0.0025" to 0.0030" (in conjunction with main bearing clearances increased to 0.0020" to 0.0025"). But installation of a high volume oil pump alone without taking any measures to control where the extra oil was flowing would also supply more oil to the camshaft bearings and the valve train. So to control the oil flowing to the camshaft bearings the small restrictions from the Moroso cam bearing restriction kit were installed, and push rods having restrictions in the tips or thick wall 5/16” OD push rods with 0.072” passages through the middle were installed to control the oil flowing to the valve train. In this way the extra oil supplied by the high volume oil pump was routed as best as possible to the rod bearings where the clearances had been increased. This was the lubrication scheme Ron Miller liked to use (Ron Miller's shop was one of my hang-outs in the 1980s).

Engine RPM is only part of the equation regarding the need for tappet bushings however; the lift rate of the camshaft lobes is another part of the equation because it affects the speed of the tappets. In turn, the speed of the tappets is going to affect the severity of cavitation at any given rpm. A modern 351C street cam can easily lift the valves 0.570” to 0.600" off their seats (or more!) in a relatively short duration, therefore those tappets are moving a lot faster than hydraulic camshaft tappets did 40 years ago. Modern cam grinding equipment allows cams to be ground which lift the tappets very fast, even in modern street cams. So although we all once believed the bushings were strictly a high rpm solid lifter motor modification that is no longer the case.

In light of the diagnosis of cavitation and oil leakage being the root problems with the 351C lubrication system, the installation of tappet bore bushings is given heightened credibility as the logical way to prepare the lubrication system of any 351C performance motor, street or otherwise. I am of this opinion for three reasons (1) because it is the only measure that isolates the tappets and tappet bores from the oil passages thus eliminating cavitation in the main oil passages, (2) it is the only measure that prevents oil being bled away from the lubrication system, and (3) because the reasonably priced do-it-yourself tappet bore bushing installation kit available from Wydendorf Machine (selling for approximately $400 USD) makes it affordable and within the budgets of a large range of engine projects. Denny’s kit is a better kit than the kit once sold by Ford, and the price is substantially more affordable.

The alternative is to:

(1) Live with the fact that there is some degree of cavitation occurring within the lubrication system
(2) Live with the fact that there are 16 leaks equivalent to one 7/32” hole bleeding oil away from the parts of the motor that require lubrication.
(3) Take steps to insure the motor is operating at the pressure specified by Ford (50 to 70 psi hot oil pressure by 2000 rpm)
(4) Hope the oil pressure doesn’t sag in the upper rpm range due to cavitation or oil leakage
(5) Limit the maximum engine speed to whatever rpm the owner thinks is safe
(6) Hope cavitation is not too severe below that rpm.
(7) Limit the amount of oil flowing to the valve train via the push rods.

Limiting a 351C equipped with 4V heads to a “safe” engine speed, such as 6000 rpm, is incongruous; as is living with a cavitating lubrication system when it is so easy to fix while you have the engine apart. Tappet bore bushings having 0.060” orifices combined with 5/16” restrictors in the passages supplying oil to all 5 camshaft bearings (also having 0.060” orifices) provide the following benefits:

(1) They eliminate cavitation in the main oil passages
(2) They eliminate oil being bled away from the lubrication system via the tappet bores or the camshaft bearings
(3) They alter the lubrication system to function as a main-priority system
(4) They eliminate tappet compatibility issues
(5) They limit the amount of oil flowing to the valve train
(6) Hot oil pressure is no longer an issue because the lubrication system operates at generally higher hot oil pressure when the bushings and restrictors are installed; yet the bushings and restrictors also make the lubrication system capable of functioning very well with lower pressure
(7) The main and rod bearings will be properly lubricated at any conceivable engine speed
(8) They repair excessive tappet bore wear on high mileage blocks
(9) They prevent the loss of motor lubrication if a tappet pops out of its bore.

In all sincerity, if a person installs the tappet bore bushings in their motor they shall not regret it after they observe how well the lubrication system performs once they get the engine running again. In fact most people who have installed them say they'll never build another Cleveland without them. Of course, you need a good gauge to observe that. You can look upon bushing installation as fixing the lubrication system or as hot-rodding the lubrication system, whichever perspective makes you feel better about installing them; either way the bushings are a big improvement. In my opinion it’s the best thing you can do for the lubrication system. If you’re only going to make one modification to the lubrication system, that’s the one to make. It’s far more beneficial than things like high volume oil pumps. The price is right using Denny's kit.

-G

Wow, superb write up George, lots of valuable information.
Regards,
Tony.

ALL Ford engines, including "High Performance" engines had basically a 6,000 rpm maximum intended rpm. Normal production vehicle use.

Go right down the list if you so choose.

In the case of Ford, I can think of the 289HP, Boss 302, Boss 351, 427, 428cj and scj, Boss 429. You may be able to think of more?

They were never sold to the public for use on public roads as "race engines".

In fact, hydraulic lifter engines had 5,500 rpm limitations. Some may think of this as design faults but what exactly is wrong with an engine doing exactly what it was designed to do in production?

Maybe the most famous of all, the 427 "side oiler" in one of the most famous RACE applications ever for it, LeMans 1966, was limited to a maximum of 6,000 rpm. In that race three Ford GT40 MkII's finished 1, 2, 3.

This discussion is all very subjective and all a matter of opinion but the reality, beyond opinion is that anything happening over those operating rpm's can't be considered a design fault. They were never intended to go over that.

The reality is that all of these engines operated very well in their intended usages.

If anyone finds fault with them and is disappointed, then look within. The issue is with you.

If you want to make blanket or specific accusations of oil pump cavitation under the intended use, go right ahead. How you are going to make this case is beyond me. You can not prove something that does not exist.

George, thanks very much for the detail on the different "fixes" conjured up over the years. It's very helpful to have them all in a very concise order with pro's and con's as well as a history behind them.

quote:

Originally posted by PanteraDoug:


If anyone finds fault with them and is disappointed, then look within. The issue is with you.

If you want to make blanket or specific accusations of oil pump cavitation under the intended use, go right ahead. How you are going to make this case is beyond me. You can not prove something that does not exist.

I personally think the 351 Cleveland is the best thing ever to be cast out of iron.

I find no fault with it but that is not to say it can not be improved upon.

I think the stock 4v heads are perfect, but plenty of others feel grinding bits out of them here and there improves them.

I think the stock rocker pedestals are fine, but others like to machine them down, redrill them and fit 7/16" rocker studs.

I think the old flat tappet cam and lifters are fine, but others like to change all that to a roller setup.


None of these things constitute a fault with the original engine.

As you say, all of these things were fine for the "engines intended usages" but all and more are modified to "improve" them.

I see no difference with or special circumstances to exclude the lubrication system from this philosophy.

quote:

"You can not prove something that does not exist ?"

Proving things requires evidence.....but..

The absence of evidence is not the evidence of absence.........



A man goes to the doctor and says:......."Doctor i'm in terrible pain and i feel really ill"

The doctor does a bunch of tests, scans, and xrays.

Then the doctor says to the man:........."I can't find any evidence of anything wrong with you, so therefore there must not be anything wrong with you"

The man says in response:................."Well regardless of that, obviously there is something wrong, i'm still in terrible pain and still feel really ill"...."just because you have not found evidence of what is wrong does not mean there is nothing wrong, all it means is you simply have not found evidence of it".

The absence of evidence is not the evidence of absence.........

I recently pulled down a 351c and all the rod bearings were shot......i found nothing obviously wrong with the engine otherwise.......does that mean there is nothing wrong with the engine ....????

I don't see what's so hard to grasp ? that the gerotor is likely cavitating to an acceptable degree near intended redline, and is cavitating more beyond intended redline. push it farther & you start losing the bottom end... proven

same concept in the water pump, spin it too fast and the engine temp rises... it's not because the coolant is moving too fast to remove the heat, it because the impeller is cavitating & there isn't as much coolant moving as there was at 1/2 the rpm with maybe an acceptable amount of cavitation

In the cooling system getting rid of the paddle fan and installing a pump with a real cast impeller drastically increases flow thru the rpm range and reduces cavitation.

As in a commercial cooling and heating systems these systems are missing some critical components. Suction diffuser and balancing valve.

Otherwise as i think DOUG mentioned you need to go to a DRY SUMP system ... personally that small rubber belt has always been the weak link.

quote:

Originally posted by accobra:
... personally that small rubber belt has always been the weak link.

Small rubber belt ...??

quote:

Originally posted by Aus Ford:

quote:

Originally posted by PanteraDoug:


If anyone finds fault with them and is disappointed, then look within. The issue is with you.

If you want to make blanket or specific accusations of oil pump cavitation under the intended use, go right ahead. How you are going to make this case is beyond me. You can not prove something that does not exist.

I personally think the 351 Cleveland is the best thing ever to be cast out of iron.

I find no fault with it but that is not to say it can not be improved upon.

I think the stock 4v heads are perfect, but plenty of others feel grinding bits out of them here and there improves them.

I think the stock rocker pedestals are fine, but others like to machine them down, redrill them and fit 7/16" rocker studs.

I think the old flat tappet cam and lifters are fine, but others like to change all that to a roller setup.


None of these things constitute a fault with the original engine.

As you say, all of these things were fine for the "engines intended usages" but all and more are modified to "improve" them.

I see no difference with or special circumstances to exclude the lubrication system from this philosophy.

quote:

"You can not prove something that does not exist ?"

Proving things requires evidence.....but..

The absence of evidence is not the evidence of absence.........



A man goes to the doctor and says:......."Doctor i'm in terrible pain and i feel really ill"

The doctor does a bunch of tests, scans, and xrays.

Then the doctor says to the man:........."I can't find any evidence of anything wrong with you, so therefore there must not be anything wrong with you"

The man says in response:................."Well regardless of that, obviously there is something wrong, i'm still in terrible pain and still feel really ill"...."just because you have not found evidence of what is wrong does not mean there is nothing wrong, all it means is you simply have not found evidence of it".

The absence of evidence is not the evidence of absence.........

I recently pulled down a 351c and all the rod bearings were shot......i found nothing obviously wrong with the engine otherwise.......does that mean there is nothing wrong with the engine ....????

"I went to the Doctor for a check up" and the Doctor said, "you're getting a little chubby, you need to loose some weight". I said, "I'd like to get a second opinion".

He said, "OK...and you're uggly too?"


Ron is refering to systems that always seem to find the weak link.

The dry sump system has external pumps that are belt driven. The belts tend to get over stressed and fail.

In many cars the systems themselves cause a great deal of stress to the installers, mechanics, and the cars, etc, since the vehicle themselves often need to be modified in order to find room to install them.

This often can cause issue with failure or weaknesses introduced in order to install the system itself which in the case of a dry sump is quite extensive.


I love to see full comp cars and see where they have been modified to accept the modifications...get that?

I like cars that were never initially design as race cars like the Pantera. I'm not going to Lemans but like to see what engineering changes needed to be instituted to do that.


There are many differences between Ford GT40's and Panteras but one of them is the differences between the race oiling systems.

I have not seen any of the vintage factory race Panteras originally with dry sump systems. The big Aviaid pans with external oil coolers seems to be all that was needed.

I 100% agree that sleeving the lifter bores is mandatory in a race Cleveland. For a race car, that is "no biggie" at all.

There are two cars, the Pantera and the GT40 that seemingly have so many similarities. One makes a better street car than the other, and one a better race car that the other. To me, it is very interesting to see why. I like to compare the engineering differences.


In a 289 I can only think of a couple of Shelby cars that ever even ran dry sump.

Not many at all.

I think much of this has to do with rpm limitations.

If you go into the 221-260-289 Ford Indy cars of the vintage early '60s you will definitely see them but you are also talking about an engine that was turning substantially higher rpms than even the race Cobras and GT40's were.

Every engine is going to have it's ultimate limitations. The Cleveland never proved to be a good high rpm endurance engine.

The Lemans effort race Panteras had issue with crankshaft failures due to the internal balance weights being thrown out of the crankshaft.

Those were built by Hank the Crank for Holman-Moody.


(Ford actually cast aluminum 351c blocks AND HEADS in 1968 for what they referred to as an "Indy racing effort". How many of those engines have you EVER seen? Ever seen those in a Pantera Gp4 car? I'll bet that you haven't?


The cranks worked for US NASCAR engines with little issue. When you put them into a Lemans car and the engines blew up then I would think the engine was being stressed farther than the US racing ever had done?

You need engineers that can manage these issues. The GT40 427 Ford engines were limited to 6000rpm and still finished 1,2, 3, at Lemans in '66. That is management if you ask me.


I went to the Doctor again and said raising my right arm, "it hurts when I do this". The doctor pushing my arm down said, "don't so that"?

Some of you guys I think just miss the obvious? There is no issue with oiling of the 351c within it's original intended usage as a street car, in your LTD Country Squire station wagon with MAYBE a 6,000rpm limit. Everything else above that is at your own risk.


Again, the Cleveland is no worse or no better than any other production engine ever made when raced. Your imagination is what is having issues.

Aluminum Ford Cleveland block ^^^^. Another shot.vvvv The Heads are the Motorsport B351 heads(from about 1985) but the block has 1968 casting numbers, Ford markings and definitely is a Cleveland.

Pictures from Jeff Burgy.

I believe he said he bought this from Rousch.

It was hurt and has a welding repair in the lifter gallery but it is all Ford.

Ford apparently GAVE these blocks away to the serious Pro Stock racers in '71-2-3, and guys like Gapp&Rousch and "Dyno" Don Nicholson used them for match races.

I don't have pictures of the aluminum heads but am told that they used the same molds as the iron heads did.

Hey. don't shoot me, I'm only the piano player. It pays to hang around like a fly on the wall sometimes. People forget you were there or better yet, never saw you there to begin with?

(Don't tell Jeff, but those are my heads and oil pan on his block? That's my porting on the exhausts. )

Another view.

Funny. I don't see bronze lifter sleeves in there? Do you? Maybe that's why it blew up?

Probably saw 10,000 rpm on more than one occasion with those hot dogs drivin'?

quote:

Originally posted by PanteraDoug:



There is no issue with oiling of the 351c within it's original intended usage as a street car, in your LTD Country Squire station wagon with MAYBE a 6,000rpm limit.

Hey don't knock it, some of those LTD Country Squire station wagons really hammer.



I think i would sleeve that block with all the damage and welding on the front two lifter bores, just to make sure the bores are square to the cam.

quote:

Originally posted by Aus Ford:
[QUOTE]Originally posted by PanteraDoug:



There is no issue with oiling of the 351c within it's original intended usage as a street car, in your LTD Country Squire station wagon with MAYBE a 6,000rpm limit.

Hey don't knock it, some of those LTD Country Squire station wagons really hammer.


{/QUOTE]

...AND you can carry just about everything you own in them AND tow your car to the track with it too!

They should forget about SUV's and bring back the station wagons!

That block definitely needs alot of TLC!