Hey all,

To the point, 1991 Formula, 305 TPI. Just had a Tremec 3550 installed along with a new Hays flywheel, Centerforce 1 clutch, roller pilot bearing and, a new throw out bearing. Now, in neutral with clutch engaged or disengaged, there is an engine vibration from idle all the way up, more noticeable the higher you go. It doesn't shake the car apart but it's definitely a seat-of-the pants there . Clutch engagement is smooth and there is no chatter at all. The mechanic I brought the car to says tight valves or a miss and another mechanic says the timing is off. If anybody is in the know, could you clue me in?

Scott

 

it could be the motor mounts.

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'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei distributer
'95 3.23 rearend
hotchkis rear suspension
PST front polygraphite suspension

 

I'd suspect the flywheel or clutch, or both, is out of balance...

Try unbolting the cluctch from the flywheel and turning it 180° and bolting it back up

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"So many Mustangs, so little time..."
ICON Motorsports

 

The flexplate, (not exactly a flywheel) on an '88 has to be indexed on the crankshaft correctly because it is not neutral balanced, (it has a weight on it). There is *usually* a dowel pin that locates the flywheel/flexplate correctly but I've seen some without it. You have to line up the hole that a bolt DOESN'T go in to have it correct.

I'm only assuming a '91 305 is the same as a '88 350 with the one piece rear seal and the 3" bolt pattern flywheel. I could be mistaken.



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SMasterson

 

Just a little question, if the flywheel, clutch, or both were out of balance, wouldn't that cause chatter?

 

No. An out-of-balance condition (vibration) has nothing to do with uneven gripping of the clutch (chatter).

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"So many Mustangs, so little time..."
ICON Motorsports

 

My mechanic also had to lift the motor to get the Clutch Master/slave cylinder in past the headers. Is it possible what Iroc5speed said, the motor mounts?

 

Maybe; look and see if he forgot the through-bolts. If everything is there then it's not them.

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"So many Mustangs, so little time..."
ICON Motorsports