Flywheel and clutch

If you intend to do this regularly, I recommend steel or aluminum with a steel friction face which will rev up a bit faster like a big motorcycle. As for safe speeds, an OEM cast iron flywheel is probably 43+ years old so its hard to say categorically if its safe to use at any rpm- especially by long distance guess.

Once you get above 6000 rpms, most of the rotating parts- crank, rods, pistons, balancer etc are suspect. A brand new 1971 Pantera engine would attain about 5900 rpms in 5th gear (around 160 mph) thanks to its cam, lifters & valve springs.

I see, in fact my flywheel seems new but it is cast iron.

If I go with a steel one should I use also a different clutch ?

For the remaining engine I have stock rods with arp bolts, and the balancer seems 46 year old.

What can be the problem with the balancer ?

For what it’s worth, I faced the same dilemma several years ago when I rebuilt the engines in my Panteras and Cobras. After talking with a number of respected engine builders I specified aluminum flywheels and I’m happy with choice. Using aluminum in the Cleveland and Windsor based engines saved me 12-16 lbs. in the rotating assembly over the original steel flywheels. The weight savings is great but the bigger deal is effect the weight loss has on the moment of inertia. The lower moment of inertia in the aluminum flywheel provides much faster throttle response, which results in faster acceleration and deceleration. Another bonus is that it suppresses wheel spin and I believe is much kinder to our expensive ZF transaxles.

While they were more expensive than steel, my aluminum flywheels are re-buildable as they have a thick steel friction insert that dissipates heat faster, maintains a flat friction surface and reduces the likelihood of distortion.

quote:

Originally posted by Jérémie:
For the remaining engine I have stock rods with arp bolts, and the balancer seems 46 year old.

What can be the problem with the balancer ?

The stock 4v balancer is a "street" balancer intended to be used within it's 6,000 rpm limit.

If you change the cam for one with more lift and duration, valve springs, etc, and it is now capable of 7,000 or above regularly, then the stock balancer is insufficient.

The engine, 351c, is subject to developing engine harmonics (vibrations) above 6000 rpm.
You need a better balancer, but IMO, a balancer with the mass of the Boss 351/ho unit. It has to be heavy enough to dampen the vibrations.

Some will say that I am "full of it" you just need a good balance job on the reciprocating assembly. I disagree...on both accounts.


The Boss flywheel is cast iron and theoretically is fine for above 6000 rpm use.
Why it gets changed to steel is really as a safety concern.



I would tell you to get the Centerforce dual friction clutch, but an 11", not the pre-packaged direct Pantera 10-1/2" unit.

Be warned though that combination NEEDS to be seated. It initially slips like a son of a gun. Reason being is the flywheel is harder in steel, that side of the disc is the hard side and it takes longer for those two to come to some sort of an agreement.

What you will feel will be like you just hit a slick in the road, i.e., oil or the like and the wheels just jerked through it, but it wasn't the tires, it was the clutch just slipped. It's a very strange scenario.

I've used the Centerforce dual friction in several cars and they all did the same thing.



The rest of the Pantera reciprocating assembly with ARP rod bolts is pretty sturdy.
The only reason you would need to go to a forged steel crank would be to reduce the bearing inbedment into it's surface and thus reduce the amount of times you need to re-cut the crank journals.

Also, the Boss351 has got a slightly different balance spec then a 4v does. So the balancer and flywheel will be in slight inbalance when installed on a 4v assembly.

WHATEVER YOU DO, when you have the assembly balance, balance it as an assembly and give very specific instructions DO NOT TOUCH THE FLYWHEEL AND THE BALANCER.

You need to be able to change those in the future without having to worry about rebalancing the entire assembly.

A knowledgeable, experienced and conscientious professional should have no issues with that BUT I personally have had one engine, a very expensive 447 Ford screwed up by the balancer.

It loosened all the main caps within 20 minutes of running. Only a mis-balanced engine can do that.

Thanks for the answers.

I totally forgot to say in this post that I have a 1970 Mach 1 and not a pantera.

I don't know what are the differences, but I guess theory about flywheel steel vs iron, and balancer behavior remains the same.

@ Shadetree, I thought to this lighter flywheel but I'm worried about the driveability, maybe it will hurt it, my car is a road car, a mustang most of the time to be driven normally on the country side. Also the problem is that cost may be quite high (for aluminium) ( + shipping to EU ...... )

@ PanteraDoug

I see exactly for the balancer, maybe I should go for an hydraulic damper to protect the crank.

For the balancing I see also, in fact one of my question was the one you answered : what will happened after having balanced every thing if I want to change some thing. But If I understood well component you buy afterward are supposed to be already prebalanced like the one I would remove. And that's clear for me too that well or not balanced it does not changes really the centrifugal forces the flywheel will see.

For the clutch I have at the moment a trinagle shape mechanism, with a standard friction. Since I'll run maybe a biger cam or the same I see only the compression ratio as source of additional torque, so I was wondering if it was worth changing it as It is new and did not slip. (should I balance it separately at zero ?)

Regarding the flywheel, I saw a 90$ one on ebay, and a 160$ one I though they would be in any case less brittle than my cast one, what do you know these kind of parts ? are there some counter indications to use them ?

I've been told also to have a look to the windsor 302 flywheel which bolts on the cleveland with less inertia, any one has tried ?

PS PanteraDoug : my head are at the machinist, guide OD are cut away ready to press the bronze ones you ordered for me

Jérémie

what do you think about this : http://www.ebay.com/itm/261859...T&fromMakeTrack=true

The people who balance these assemblies want to do it the easiest way. That is taking weight off of the flywheel and balancer.

Iron flywheels usually show cracks even new from the casting process. They could develop into failure lines. Steel doesn't normally do that.

It's more important in drag racing when you are reving the engine and dropping the clutch. That hits the flywheel like a sledge hammer.

The 4v engine was built with "competition potential".

You don't need to do a lot to them to race them BUT you do need to do some things.

The big balancer is important to the Cleveland to race it. On the street? Nah.

Those guides are pretty aren't they?

Guides are just fine, I have stainless EPN valves the combo seems perfect regarding clearance.

They are not pressed yet, I also need to define the dimensions of my seat 3 angle cut.

It's funny that you talk about going the easiest way .. in fact when I tried my car it seemed to have a heavy H1 harmonic that was really easy to feel off the idle. when I disassembled the engine I realized that pistons were changed, I check the wieght and they were equal to each other, BUT I saw nowhere any signs of balance, the crank seem absolutely untouched on the counter weight, flywheel also harmonic balancer the same.

So I guess my engine was basically unbalanced even on the first order : I mean the counter weight were not suitable for the pistons installed, and ... last but not least I think this has lead to destroy my shock towers ...

this is only one of the many things a retard has made to this engine... there's also cracked guides OD you know Cylinder head with much more volume than the other one ....

An engine builder told me that if the reciprocating parts are within 10% of the originals they do not need to be rebalanced.

Ford is old time stemming from the days of the Model T.

Their internal engine parts are theoretically ready for the "proverbial farmer" to change on the tractor stuck out in the fields?

Pistons were always like that and many many engines had their pistons and rings changed without ever even seeing a hone and basically still run fine.


In fact, Mark Donohue in his book, "Unfair at any speed", remarks that in regards to the Camaro (Roger Penske's) that they had found the perfect condition of the short block just being "friendly enough" with it's parts, read that as on the loose side, and the heads being nice and tight and precise.

Considering the results, AND the source, I defer to the higher authority on that?

Wow you lost me

Not sure what you wanted to say ! (I'm not native speaker)

To answer your earlier post, the stock 3-finger clutch is fine up to maybe 500 bhp. Changing clutches is only done if
-A- your OEM is slipping at high torque,
-B- the effort required to push in the pedal is too high for comfort; in that case a diaphragm clutch is easier to push in and has about the same holding power as a 3-finger.
Or -C- the disc is worn out or pressure plate is broken.

Note that if changing flywheels, most aftermarket units are drilled for multiple patterns while the stocker is only drilled for the stock Long 3-finger. Redrilling and tapping is a job for pros. I'm looking at a nice Weber cast-aluminum flywheel in a shop, in which someone stripped ALL the clutch bolts out while installing the assembly. The flywheel is now worthless. Torque wrenches are required!

If you're going to that much trouble, I also suggest changing the throwout bearing AND the pilot bushing in the end of the crank. Reason is, they wear out too and changing them requires the trans to come out, so most of us do it whenever the gearbox is removed. Parts cost is minimal compared to the labor required to change either later on.

quote:

Originally posted by Jérémie:
Wow you lost me

Not sure what you wanted to say ! (I'm not native speaker)

OK, a synopsis. 1) you can be up to 10% out of balance without issue 2) You can make lots of power with a loose bottom end 3) there is a degree of inaccuracy for the bottom end assembly where the short block is still very usable

Ok thanks doug, I see now

That's good if I can stick with my current balancer it saves me money to buy something else.


@ boss wrench, that is a good news if the clutch can cope with 500hp, with one single carb few chances that I reach this level of power.

My clutch looks new but I will check if the friction is close to its thickness when brand new. I saw some frictions with 4 pads which are supposed to be better than oem is it worth putting that ?

For the pilot bushing I have also bought a new one built in a needle bearing, not changed the throw out one but will do it.

For the flywheel I did not understood the end of your explanation.

Do you know if a 302 clutch fit to a 351C ?

Regards.

I never said you didn't need a heavier dampener?

A pilot bearing is not the way to go. Stay with a bushing. Bearings fail. Bushings don't.

quote:

Originally posted by PanteraDoug:
I never said you didn't need a heavier dampener?

A pilot bearing is not the way to go. Stay with a bushing. Bearings fail. Bushings don't.

I did not understood quite well again, I though you said in thos post (see bellow) that It was mandatory to go to a new balancer only for racing.

quote:

The big balancer is important to the Cleveland to race it. On the street? Nah.

Bad luck for the pilot bearing, I read in a book (or somewhere else) that needle bearing was the way to go.

Has any one an idea where I can find a good deal for this flywheel ?

I checked mine, it is a 164 tooth, and after looking on the internet it seems that they are also used on 302/351 windsor.

Last thing, what's the weight of the stock one ? is 30 Lbs the correct weight ?

The rpm use is what determines the balncer. Under 6000 rpm, 4v is ok. Over, you need more mass.

Don't believe everything you read in a book.

It's your engine to do as you choose. There is no advantage to a pilot bearing vs a bronze bushing.

Where's Marlin at? Perhaps he would explain?

it's been suggested that sintered clutch material will tear up a bushing where the roller bearing will last, didn't make sense to me?

You talk about the pilot bushing into the crank ?

If yes for the the bushing should be kind of oiled sintered bronze, but it is in contact with the shaft of the gear box but not the clutch ?

Or maybe I understood things wrong again!!!