Stroker engine vibration

Of course there is no way to truly diagnose this via email so one hypothesis is as good as another. I suspect the balance of the new flywheel is not consistant with the steel flywheel. Or, perhaps the new flywheel's bolt holes are drilled slightly different from the steel wheel. Or, maybe they didn't zero balance the pressure plate very well and it doesn't complement the new flywheel. Or, perhaps the bolt holes for the pressure plate on the aluminum flywheel are slightly askew from the steel flywheel creating an imbalance.

This is a frustrating problem and I have felt your pain in the past. Difficult to correct without taking the new parts back to the machinist for balance.

BALANCE IS EVERYTHING. I wrote that in capitol letters on purpose. You could swap back to the steel flywheel and see if that corrects it. Not too bad to pull the tranny. Maybe the machine shop could match the balance of both flywheels out of the car?

quote:

Originally posted by Push1267: I have a vibration issue with my 427 winsor stroker. It vibrates quite a lot all through the rpm range. Although the crank, balancer and flywheel balance should match (see below), I suspect (fear) that it’s crank imbalance. Could it be something else? Kristian

Kristian, there's an outside chance the reciprocating assembly and flywheel are just fine and the clutch/pressure plate mounting is slightly off. Depends upon how well it was centered during mounting or I suppose slight differences in mounting hole patterns on the flywheel though I would doubt the latter as it is pretty basic for such a manufacturer such as Fidanza.

Was it difficult to mount the transaxle? It is not at all uncommon for the bellhousing dowells to be off. Offset dowels are made, though the symptom here is usually difficulty assembly and possible pilot bearing failure though it also imparts a lot of stress to the input shaft. Can you discern difference in severity of the vibration when clutch is/isnt engaged? Even though the pressure plate is always attached to the flywheel, slight diffrerences in centerline of pressure plate mounting thus clutch/input shaft to the flywheel can cause chatter upon clutch engagement and vibration under power.

-Just a thought.

K

Thanks guys for you help. I really appreciate (and need) it.

quote:

Maybe the machine shop could match the balance of both flywheels out of the car?

I don't have the original flywheel so side-by-side comparison is out of the question. I bought the engine secondhand with only a few hours on it. Dynotime and a few miles on the road.

quote:

Can you discern difference in severity of the vibration when clutch is/isnt engaged?

No, vibration is the same whether the clutch is engaged or not. The clutch is a Mcleod diaphram and trans a ZF-1. Pilotbearing is an oilite custom piece by Marlin Jack. I didn't have any difficulties mounting the transmission. I thought about pressureplate centering too - there are no dowel pins in the flywheel to center it during installation - so it's done just by the bolts alone.

Another thought I had was if the engine isn't running on all 8 cylinders. The engine been sitting for 2 years so something may have occured - like a collapsed lifter? I didn't check if all the header pipes were hot as an indication of that - so I'm not really sure. Would that create a strong vibration also?

Kristian

Kristian,

If you are not sure about the engine running well, that's the first and easiest thing to check. Pull all 8 plugs and compare. If something isn't firing you will see a difference in the plugs. I hope that's all it is. Internal balance issues are tricky to address, as noted above. Good luck!

Mark

I had the same problem. I replaced my external 28oz flywheel with another and it shook like mad throughout.
You need to get the new flywheel match balanced to the old.
Will

quote:

I thought about pressureplate centering too - there are no dowel pins in the flywheel to center it during installation - so it's done just by the bolts alone.

Did you use "Pressure Plate" bolts to fasten the pressure plate to the flywheel. The correct bolts have a shank on them that locates the pressure plate correctly...

Unfortunately I don't have the old steel flywheel to match balance against. I have the the engine buildsheets showing which flywheel was originally there, but they alos state that the rotating assembly was balanced. Who knows what was done to the flywheel.

The pressure plate bolts are new ARP bolts with a shank. However, there was a small problem with 3 of the bolt holes in the pressureplate being slightly larger than the other 3. The other 3 had a tight fit. Only that particular bolt pattern fitted the McLeod pressureplate (which is std ford I think)-

I think I'll pull the transaxle first and send the flywheel/pressureplate out to check for balance. Maybe it's way off the 28.8 oz it's supposed to be.

If that's ok, I guess I'll have to pull the engine, take it apart and have the entire rotating assemble balanced.

Damn!

Kristian

quote:

Originally posted by Push1267: I thought about pressureplate centering too - there are no dowel pins in the flywheel to center it during installation - so it's done just by the bolts alone. Kristian

I was referring to the two dowel pins that locate the bell housing on the engine block. The bell housing has a a step that registers the transaxle casting to center, thus centering the input shaft. If you are going to pull the transaxle you may as well check that as well. You will need to seperate the transaxle rom the Bell housing, mount the bell housing on the engine, and then use a dial indicator to check if the step machined in the bell housing is centered on the crankshaft centerline.

This sounds less likely to be your problem since there were no assembly issues and the vibration persists whether the clutch is engaged or not. -Good luck identifying the source of the problem.

Best,
K

I agree with Marlin here.

Let me state it slightly different though. I think that it is best to tell the engine balancer person, DO NOT UNDER ANY CIRCUMSTANCES TOUCH THE BALANCE OF THE FLYWHEEL AND DAMPENER. IF YOU NEED TO, ADD MALLORY METAL TO THE CRANKSHAFT.

If you do not, they will balance the engine the easiest way for them, and that USUALLY means taking weight off of the flywheel and dampener.

If they do that, changing a flywheel or dampener will throw the reciprocating assembly into unbalance.

That is what it sounds like you have. Get the original flywheel back, any way you can. I'll bet that is the problem?

It is also a very good idea to balance the clutch as well, even a brand new one in the box.
I always have them done when I send an assembly out for balancing.

I had many engine builders tell me that you won't even see a "good" balancing job until over 7000rpm's.

I may be wrong here but if it is vibrating enough the dampener/balancer can fail on this.

In any case, best of luck with this situation.

Marlin, You are a really inteligent and helpful guy. I am extremely glad you are a part of this forum.

The dude made an honest mistake. I don't find his misfortune funny at all.

I completely agree that this could have been easily avoided with some research. Before I rebuilt my engine I did much much research. I too gave the machine shop all the parts including the flywheel, pressure plate and flywheel. I also told them that I did not want the flywheel and balancer modified so that they could be replaced in the future if required. I too have a smooth running engine because of it.

By the way "My Mommy" likes my car she lets me play with it as much as I want.

DUDE BE NICE.

It ain't my Mommy that like my car, it's my Mama. She calls me Sugar!

edited

Kristian you have my sympathy, I'm sure you're feeling pretty bad already.

The thread didn't get off track when Marlin made his comments; its getting off track when members start judging the post of another member. Lets all stay on topic, which is Kristian's Pantera motor. The topic is not our personal opinions of Marlin. That's not what some of you wanted to read is it? I may end up editing some of the comments about Marlin ... and Marlin's replies to those comments. Nobody get all bent out of shape, OK?

There are a few lessons here in regards to Kristian's motor ... here's my two cents.

The manufacturers of inexpensive crate motors are not going to use mallory metal to balance a reciprocating assembly via the crankshaft, mallory metal is very expensive, the crate motor manufacturers want to keep the retail price of the crate motors as low as possible, but they also want to make a nice profit. So they balance their motors as inexpensively as possible ... possibly using the flywheel and damper. If there are signs of that having been done, those parts need to stay with that motor.

The billet steel flywheel was the better part anyway. Its tough, durable, safe. It will last a long time without giving the owner any trouble. Aluminum has a bad tendency to work harden and crack. Aluminum is not a good material to use on reciprocating assembly parts, except in situations where the motor isn't expected to last a long time anyway.

The lure of an aluminum flywheel is to make the motor rev a little faster. But stop and think for a moment. A 500 foot pound stroker motor installed in a vehicle equipped with street tires doesn't need to rev any faster, its just going to be that much easier to break the rear tires loose, its going to make traction harder to control. A seven liter V8 with a 4" stroke crankshaft is a tire frying beast. The extra weight of the steel flywheel is actually a good thing for such a powerful motor used in a street application. The limit to the car's acceleration is going to be traction, not the weight of the reciprocating assembly.

-G

Not trying to distract anyone but in thinking about my stroker crank, when it came back from balancing, it looked like swiss cheese.

The flywheel and balancer were left factory stock and thus came back untouched.

In talking to the crank manufacturer (Eagle) they said the design takes the cost of Mallory into consideration.

They claimed their cranks are designed to come into balance with removing metal from the crank only.

The balancer took quite a bit off of the counter weights on mine. They are designed for that but longevity on any stroker crank I would suspect is going to be significantly shorter then stock.

Doug,

I was thinking the same thing ... and will check but i thought my engine was changed to internally balanced assembly ... could be wrong because I too remember the SCAT crank being made into Swiss cheese also with only metal removed. I gave him everything including the double disc clutch and aluminum flywheel assembly with the fluid damper.

Ron

Incredible .

It's just an engine, time and money - nobody died - no need to get upset!!

I posted to get thoughful insight and I got that - and little bit more. I now know what to do - thank you all for your help - let's leave at that.

Although it's frustrating, it's really not that big an issue. The engine is comming out tonight, I'm stripping it down and sending everything out for balancing. With a little luck I'll have everything up and running (smoothly) in a couple of weeks. The weather is still really bad in denmark so I'm not missing quality street time - that's good ! (for me at least).

I admit it may have been naive to think that the engine builder would always balance the crank - not the flywheel. If the engine builder was still in business I would have asked him - and if the original flywheel was available I would have used that to match balance. I don't have those options unfortunately.

I was looking through some old pictures of the engine from when I changed the oilpan. Looks like quite a lot of weight was taken out at both ends of the crank.


Kristian

That could be my front counter balance. It was the big hole that concerned me since you can measure in thousands how much material was left.

I think my rear counter balance looks the same too.

Frankly with a steel crank it must me an SOB to drill those out even on a drill press and be accurate.

My thought on the vibration is also that in my experience, you need to be really out of balance to pick up a vibration. Theoretically there is exact factory balance on the flywheel and dampener but talk to your engine balancer about that.

The thing to do in this instance is to get a new steel flywheel, install it on the engine before you tear it apart and see if it fixes it.

Location dowels in the flywheel for the clutch will sure help the situation and the clutch cover and the flywheel should be indexed.

The problem with having the clutch balanced is that no one is going to want to take it apart to remove weight from it.

Most likely what will happen is that it will get balanced along with the assembly. I'm not sure how good an idea that is at this point? I have to think about that.

Aluminum flywheels regardless of how accurately they are balanced do not absorb engine vibrations well because of lack of mass.

In any event, re balancing the entire unit will fix it, but make sure you use factory balance on the flywheel and dampener.

This has been a very interesting thread on engine balancing and I've really enjoyed reading everyone's two cents worth on the subject. I'd like to suggest a few easy items I'd check before tearing the motor apart to check for an imbalance issue:

1. Double check that the plug wires are routed correctly. SB fords have 2 different firing orders 1-5-4-2-6-3-7-8 or 1-3-7-2-6-5-4-8 depending on your cam. It's easy to swap the back 2 plugs on either side, I've done it. Motor runs like crap.

2. Visually check the condition of the cap and rotor, ohm test the plug wires for continuity.

3. Check the plugs(previously mentioned) They should all look about the same, an odd ball in the bunch is suspect.

4. Pull valve covers and check the valve train for broken springs, broken rockers, bent push rods, or other malfeasance.

I had a vibration develop in my Cleveland once. Turns out I broke a valve spring. It broke the very first coil and would still hold the valve closed, but didn't control it properly which resulted in the vibration. I got real lucky on that one, didn't hurt the engine at all and only a little pain on my wallet.

Hope this helps, If you want more suggestions or help with the trouble shooting, just ask........J

PUSH1267,

The thing that still rubs me the wrong way with this thread is the unfavorable response to your initial request for thoughts and opinions.

I guess when a respected member responds in this unfavorable manner 2 things happen ... it creates a climate where persons might not post and the respected member looses the respect in 2 posts which had taken him ... many years to earn.

Just a thought.

PS. Mustang JP I think you hit it on the head ... I have experienced the same issue with the firing order and broken spring on my 428cj.

Ron

The picture of the motor with the pan removed sure makes it look as though all the balancing was done by removing material from the counter weights. Thinking out loud here, I wonder if the vibration problem may be resolved by installing the same make & model flywheel the motor was built with (RPM billet steel external balance flywheel #FPH-30228 RPM).

I've got a story for you guys; the Pantera belonging to an original gangster member of this forum, Tom Edds, received a tune-up one afternoon by Tom's son, who inadvertently crossed two of the spark plug wires. After the tune-up Tom took his Pantera out for a test drive, and found the motor running a little "rough" so Tom figured he needed to "blow-it-out" a little. That's just what Tom did, he put the pedal to the metal and literally blew the crankshaft into the oil pan. Devastating results from just crossing two spark plug wires.

-G

I wish it would be that simple. I remember just cruising along and pulling up to a light. The engine started really running rough, like it would if the counterweight came off of the flywheel.
I wasn't far from home so I did get it home ok.

What had happened is I had a set of Crane Ultra Hard push rods in the engine (Boss351). The tips on two of them litterally crumbled off of the tube.

I was lucky to get the metal out of the heads before they got into the oil pan. Didn't have screens epoxied into the drain back holes like a lot of racers do.

Crane apologized and said it was "bad metal" that caused it and gave me a new set.

I thought for sure I blew the engine with the vibration the engine made.

This is the type of thing that over the years as one accumulates experiences, that counts to the knowledge base of ones own data bank.

I had a friend who was a former Prostock racer that I'd ask questions of because of his "intelligence". He once said to me, "thanks but I'm not highly intelligent, I'm just highly experienced".

As far as an unfavorable response manor goes, it reminds me of the film, "Cranky Old Men".

Thanks again. The engine is coming out tonight.

George, although you may be right about the flywheel, I'm not taking any chances by putting a new RPM flywheel back on and installing the engine back in just to find that it's still unbalanced.

I've talked to a local machine shop that can do the balancing work - so I'll be sending the rotating assembly out as soon I've made sure that nothing is wrong with the pushrods, lifters, spring pressure etc.

Also, I need to check the part number of the crank. I did check the harmonic balancer, and it's NOT the same as stated in the build sheets - pioneer vs professional products!! Makes me wonder what crank and flywheel was in it. I'll check the crank - Maybe it's internally balanced - we'll see.

Kristian

quote:

Originally posted by Push1267:
Thanks again. The engine is coming out tonight.

George, although you may be right about the flywheel, I'm not taking any chances by putting a new RPM flywheel back on and installing the engine back in just to find that it's still unbalanced.

I've talked to a local machine shop that can do the balancing work - so I'll be sending the rotating assembly out as soon I've made sure that nothing is wrong with the pushrods, lifters, spring pressure etc.

Also, I need to check the part number of the crank. I did check the harmonic balancer, and it's NOT the same as stated in the build sheets - pioneer vs professional products!! Makes me wonder what crank and flywheel was in it. I'll check the crank - Maybe it's internally balanced - we'll see.

Kristian

'Way to be a MAN about it Kristian! We're all proud of you! Well, most of us anyway?

Hey Marlin.

I'm next. I'm guessing you don't get invited to many parties, do you?

Will

quote:

...So YOU don't think 'it' was funny? SO WHAT!!! I DO!!
And I'll tell You why!!
Honest Mistake?? A Mistake that was Easily Avoidable! By a person
who thought he knew what he was doing. He Talks Balance, but doesn't even know 'Page 1' about Balancing! IF he would have asked Just One Experienced Person, who had done the 'job' before; We Wouldn't be here now, discussing it! And he would be driving around in a very powerful, Smooth Running Pantera,(Excepting for the changed Pressure Plate)! Instead the Gentleman ventures off into 'ExperimetationLand' and ends up with an Expensive Engine that Cannot be Driven and is therefore, No More than a Piece of Junk! And he probably can't get the Flywheel Back! I think that is funny because he did Not leave things alone.
I have very little patience for naivete and NO tolerance for stupidity; especially My Own!! I do hope he has 'Fun' with it! He Caused it!!

You Better know right now...I don't 'Sugarcoat' what I respond with, on this forum! And I Don't 'Moddle-Coddle' AnyBody!!

Now Who's Next?...

OK - I'm not having the best of weeks.

The engine is out and then - when unbolting the flywheel this happens . Brand new ARP flywheel bolt head just snapped off. They were lubricated and tightned to spec.

I guess I'll have a little chat with ARP customer support tomorrow. This is not supposed to happen with expensive "quality" bolts.

I may have damaged the flywheel slightly as we had to use heat and wrigle the flywheel of.

Kristian

Flywheel with snapped bolt

> for a Stroked Cleveland/Windsor You must go with the heavier 50 Oz, Weight!
> Because You are Balancing MORE weight, in Longer Crank 'Throws', Longer Rods,
> Larger Pistons and Other Parts.

I'm coming into this discussion late but this is wrong. First of all, the
balance factor is a product of mass and distance so the units are Oz-In,
not Oz. Second, I would never balance a Cleveland (stroker or not) to
50 oz-in. OEM balance for a 351C was 28.2 Oz-In (Boss 351C's were slightly
different). 50 Oz-In is the balance factor for later 5.0L SBF and is known
to be a problem at higher RPM. With 50 oz-in, the couple across the #1 main
is large; in SCCA A Sedan racing, it's very common for 50 Oz-In 5.0L cranks
to fail at the cheek of the rod throw. 28 Oz-In seems to be fine for most
applications under 7000 RPM, though many race teams will neutral balance so
they can interchange flywheels, pressure plates, dampers, etc. without affecting
balance. The usual choices for a 351C are 28.2 Oz-In and neutral. Neutral is
where all of the balancing is done within the crankshaft, rods, pistons and the
flyhweel and balancer are symmetric (no balance weights). SCAT desings its 351C
stroker cranks to a 28.2 Oz-In. They can typically be balanced to that spec by
drilling the crank throws with no Mallory metal required providing your piston
and rod combination weight is close to SCAT's target bobweight. With a lighter
I-beam rod and piston, the SCAT 351C stroker cranks can be internally balanced
without a lot of Mallory metal. My 403C was internally balanced with $175 worth
of Mallory metal.

> If you do not, they will balance the engine the easiest way for them, and
> that USUALLY means taking weight off of the flywheel and dampener.

Yup. Dave McLain does the machine work on my engines and uses spec flywheels
(neutral and 28.2 oz-in) and does all the balancing within the reciprocating
assembly, leaving the flywheel and balancer alone. That way, if you ever have
a problem where the flywheel or balancer has to be replaced, you can simply
bolt up a new one. You have the option to match balance components but I've
never had to do that, even when switching between flexplates and flywheels.
The guys running internal balancing do this all the time but there's no reason
the 28.2 oz-in assemblies can't be done the same way.

> P. Plates are balanced at the Factory, But they are NOT Balanced to Your
> Assembly!!

Pressure plates should be neutral, within some tolerance.

Dan Jones

quote:

Originally posted by Push1267:
Flywheel with snapped bolt

Geeze-us! I hope this is the end of the bad luck for you? BUT the broken bolt shouldn't be a disaster. I've had them too. Never broke an ARP though. Would get pretty pissed if I did...both at me AND ARP!

"When 'ur hot 'ur hot...when 'ur not 'ur not!"

Kristian, When you originally installed the flywheel did it slip on the crank on and off easily? Did you match up all the holes on the wheel with the crank? Did you check if the shoulder of the bolts fit tightly into the wheel but not too tight? Snapping an ARP flywheel bolt to me indicated something was not fitting correctly i.e. it may not be the bolts' fault.

Kristian, your shop will likely catch this if the following happened. In the latest issue of Hot Rod Magazine, a man bought an engine from a 'reputable' dealer, and from day 1 it had a vibration. After going thru all the bolt-on things you did, he gave up trying to fix it, but could not drive over 70 mph due to the shaking.
Finally, a shop pulled the engine, tore it down and found a severely lightened crank that had been (apparently) balenced for a different set of pistons and rods. The crank was 93 gms out of balance where 10 grams will cause a noticable shake! The constant shaking had torn up bearings and other things inside, meaning that the entire engine needed a rebuild after the crank rework for the new balance factor. This is one of those things thats impossible to fix externally and very hard to even diagnose. But as someone said, once you've eliminated all the probable causes, what's left are the improbables.... Good luck.

OK - my engine appears to be internally balanced - that explains why it was shaking when I put on the 28 oz flywheel.

The harmonic balancer on the engine (which is the original)is for internal balance. It's a proffesional products balancer - 80006, http://www.summitracing.com/parts/PFS-80006/?rtype=7 that can be used for either 28.8 external or internal balance.
Mine doesn't have the weight on so it's neutral balance and thus the crank must be internally balanced.

Also, the crank appears to have what could be mallory metal (??) welded into one of the holes on the first through (picture). A normal procedure when balancing internally - I think.

RPM makes 4340 stroker cranks for 427 winsors with either internal or external balance. I'm waiting for RPM to get back to me on which crank it may be (I have a part of the marking on the first through of the crank).

If it's true that it's internally balanced, then I'm really upset. The engine came with 2 sheets outlining all the parts that wen't into the build. I used those to determine that the engine was externally balanced and based my flywheel purchase on that.
Now it turns out that the actual parts in the engine (crank, rods, pistons, harmonic balancer and flywheel) are different to what's stated in the papers !! I may have ended up grenading this engines based on this misinformation.

The rest of the parts in the build sheets that I can confirm appears to be correct.

The builder is out of business now, so it doesn't make sense to warn you about them. They were building a lot of strokers a few years ago, so maybe they just copy pasted a reciept from a previous build without paying attention to what really when into the build. NOT OK.



Kristian

I just read the same article in Hot Rod Mag. Good info / lessons for all. If the rotating assembly is internally balanced since you did not run the car very long should work out fine if you install a neutral balance flywheel.

quote:

If the rotating assembly is internally balanced since you did not run the car very long should work out fine if you install a neutral balance flywheel.

I wouldn't say thats 100% correct...because my flywheel set up was drilled in mutliple locations when my motor was internally balanced ... my thought is if your going to internally balance and go thru the effort ...why not run the entire assembly and fine tune each piece. I would say after this point nothing is just bolt on. This is why it pays to stay loyal to one LOCAL engine builder who keeps good records ?

Ron

quote:

Originally posted by ItalFord:
Kristian, When you originally installed the flywheel did it slip on the crank on and off easily? Did you match up all the holes on the wheel with the crank? Did you check if the shoulder of the bolts fit tightly into the wheel but not too tight? Snapping an ARP flywheel bolt to me indicated something was not fitting correctly i.e. it may not be the bolts' fault.

I think this would be worth checking real close, although there may be mismatches with balance factor as well. The flywheel needs to clocked just right with crank, if it's not,one of the holes will bind as the holes are not symmetrical. That could explain the broken bolt. Flywheel only fits perfectly in one position.

quote:

Originally posted by jannem:

quote:

Originally posted by ItalFord:
Kristian, When you originally installed the flywheel did it slip on the crank on and off easily? Did you match up all the holes on the wheel with the crank? Did you check if the shoulder of the bolts fit tightly into the wheel but not too tight? Snapping an ARP flywheel bolt to me indicated something was not fitting correctly i.e. it may not be the bolts' fault.

I think this would be worth checking real close, although there may be mismatches with balance factor as well. The flywheel needs to clocked just right with crank, if it's not,one of the holes will bind as the holes are not symmetrical. That could explain the broken bolt. Flywheel only fits perfectly in one position.

The flywheel holes line up or don't. The holes are nowhere close unless they are in the correct position.
Will

Yes. I didn't have any problems lining the flywheel holes up. Just bolted them on with assembly lube as recommended. No locktite of course.

Meanwhile, RPM have confirmed that the crank is a forged 4340 internal balance version. So, now I have a new neutral balance flywheel on the way from summit.

Thank you all for your comments - it's been a great help. Hope it will work out now. We'll see.

Kristian

Kristian, two suggestions: first, that crank does not have mallory-metal in the welded balance hole- I hope! Because drilling in from the top and slipping a slug of tungsten alloy in is way-wrong. At high rpms & high heat, the slug will fly out thru the weld (and the engine) like a cannon shell! Several cars and engine have been destroyed by such things. Pro engine balancers ALWAYS drill into a crank longitudinally which is more difficult, but the slugs stay in. That's probably just a drill hole that was then partially corrected with arc weld.
Next, your present 28-inch-oz flywheel should be able to be remachined locally to neutral balance by cutting away the small balance weight on a mill. This will save you shipping flywheels back & forth across the Big Water, and your local balancing shop will be able to correct any tiny errors in milling.