Clutch Vibration ??...

You positive its not the harmonic balancer? Can you move it at all under the car? It could be engine related still since the engine speed goes back down once you let off the clutch with it in neutral. Would think you would get a similar vibration but not as pronounced if you rev'd the engine up and held it even if you had it in neutral. It would just be more pronounced if the whole drivetrain absorbed the vibration. I realized its only got 1200 miles on it, but you never know. Would seem like something easier to check before you go inspecting the trans. Someone can correct me if I'm wrong.

quote:

the harmonic balancer

Here is a photo of what my stock-gone-bad balancer looked like.

Note the timing marks on the ring. Note the ring is now gently rubbing on the gold Aviad oil pan.

Note the 1/2" or so to the right of the balancer ring - it had slipped that much.

Larry

I have a brand new romac ... I thought about installing my old one just to check it out....

Well do the test and rev it up to like 3000-4000 and hold it for a few seconds once you have it warmed up of course. See if you get a similar vibration before you even go messing with the balancer. Just trying to take the transmission out of the equation here to help narrow it down. I have not yet done any engine work with the cleveland IN the Pantera yet so I don't want to send you on a wild goose chase replacing parts. If you do a google search you can look for tell tale signs that there is something wrong with a balancer.

You made it sound like this has slowly gotten worse over time and was nonexistent when you first got the motor running, which led me to believe something has deteriorated and not inherent with the engine build since you said the rotating assembly was balanced.

Thanks for your help, I'm going to have to start from the start and isolate it. It's horrible ....

Did this start when you replaced the clutch and or flywheel?
I replaced the flywheel on my old Pantera and was not "match balanced" and it was vibrating horribly.
An incorrect flywheel would show a problem right away.
Will

This car has been completely gone through... I used the same flywheel that was on the car when I bought it. The flywheel was surfaced and balanced on the rotating assembly... It kinda' feels like it's in the motor but the builder (whom I trust completely ) assures me that this rotating assembly was balanced to a very close tolerance. I have plans to take the car over to the builder and snoop around some more. I will eventually report back as to our findings. As for now, I am willing to entertain any past experiences of other owners... Thank you very much for listing your experience ... I am listening.

Your situation does not seen to match this possible source, but have you checked all 16 half-shaft bolts?

Motor mounts?

Larry

Following Larry's thought, U-joints?

What happens to the vibration when you decelerate from your 80 MPH test speed?

What happens when you ease up on the throttle (at the test speed) to a float position (neither accelerating nor decelerating)?

John

No changes acel/decel or float... I have brand new spicer shafts, all the fastners have been checked. The vibration is timed with the RPM. When I am running down the road my rear view is shaking like mad, slip it in neutral and the car goes almost silent, dead smooth... If I leave it in N and touch the throttle, the vibration comes back with the RPM and the vibrating frequency matches the RPM. Clutch in or clutch out, same, same.... I will say, it seems more like it's in the engine rather than clutch/bell housing... Broken valve spring??... The car runs good, it's pretty fast. It just vibrates. I will spend some time on it mid week.

Can you duplicate the vibration with the car stopped?

John

Oh yeah, it's not in the chassis at all, dead smooth... It's connected to the rotating assembly somewhere. It vibrates the car as you reach in through the back and run the throttle.. I intend on keeping all suggestions in mind and start eliminating in order of difficulty... Vibrations are stressful on the components, I need to resolve it...

Sounds like the pilot bushing. Did you replace it when 'everything' was gone through? The answer should be 'yes.' And, did you verify the ID and OD? Answer should also be 'yes.'

I had the exact same symptom with my Mustang years ago when I put a new clutch and pressure plate in it. Turned out that the 'new' pilot bushing from Kragen Auto was not quite in spec.

Just a thought or possiblity
Sometimes when an engine builder balances a engine, they add weight to the fly wheel. If the weight comes loose, suddenly the entire rotating assembly will be out of balance. Or as mentioned earlier, harmonic balancer, either way I suspect you are putting a lot of stress on your bearings.

Also sometimes, one or both halfshafts are separated during ZF removal and misassembled when the clutch job is finished. If either of the two u-joint crosses in either halfshaft are NOT dead-in-line, the car will shake like a wet dog under power.
Second, if any of the 16 bolts that hold the halfshafts to the inner & outer stub axles are even slightly loose, the car will vibrate under acceleration.
And to expand on Quikitty's post. there are TWO balance factors that Ford used: the one you need with a '71-74 Cleveland is a 26-inch-ounce factor in BOTH the harmonic balancer and the flywheel. After 1982, Ford went to a 50-inch-oz factor: twice the weight-offset. If you have a mix of early and late rotating parts, this can easily cause your problem. What Pantera vendor did the parts come from?

Thanks you guys... I can't remember where I bought my Romac, it was recomended here, blue oval mustang guy. My spicer shafts came from Pantera east. The engine builder did mention "inch ounce" blah, blah, blah... The guy is so technical my head starts spining... You can feel the vibration is from the rotating assembly. If you pull the air cleaner, you can lean on car, reach in the deck lid and run the throttle, the vibration goes up and down w/the RPM. I am completely bummed out...

Here's an off the wall solution that might be worth a try. Find someone that does prop balancing on aircraft engine/propeller assys and ask him if he can try to balance the clutch/flywheel assy through the inspection cover. On aircraft, it is a trial and error deal and takes some time. But a good prop balancer might be able to get it close. You can usually find one through a maintenance FBO in your area. Cost should be less than $250. He might not even charge you unless he can make it better.

The more you tell us, the more I lean to a bad Romac

Larry

Romac shows 4 different models for a Cleveland. Which one did you purchase?

http://www.romac.com.au/balancers_US.html

Ford Cleveland
0203
0203SA
0204
0204SA

It says P/N 0203 sport series ( on the box ) I intend on ripping into the car mid week and trying ALL suggestions.... The balancer bolt is right hand thread into the crank Yes??

quote:

The balancer bolt is right hand thread into the crank Yes??

Yes, right hand thread.

John

You'll figure it out. Is that really not normal though having the mirror shake. Sometimes when I'm driving the mirror shakes enough where its blurry and its difficult to see out of. I mean these are almost 40 year old cars and with a 351c making any decent amount of power with a non stock cam, the chassis will absorb that. Maybe I need to go for a ride in someone elses Pantera and see what its like. I have an internally balanced a4 based 308 professionally prepared with a blower making upwards of 900 flywheel hp, and with the solid motor mounts in my mustang, it absorbs everything and that car is solid. The motor mounts are a big deal, I'm guessing yours are in good shape? Have another Pantera owner with a motor making some decent horsepower go for a ride with you.

I wedged a piece of clear tubing between my mirror stem and windshield as suggested on this forum. It did work very well to dampen the stem vibration....