garys vette

Everything seems to be working OK need to change injectors yet and get a chip burned installed.

There is a vibration from the drive train. It was there before we rebuilt the engine.

We have a few things to do and to do to eliminate the vibration.

Front end alignment. Installed new R&P "Turn One"
Rebalance all four tires.
Thinking about balancing flywheel clutch assembly.
Thinking about balancing the drive shaft.

any thoughts experience it is a 1986 vert 4+3.

cv67

Does it do it in N? With clutch in or out?
Certain speed or rpm?
If its when driving check the runout on your wheels and tires that one baffled me forever dont let the wheel guy tell you "they are within spec"

whalepirot

Being there before the build, it makes sense to start with components there, then. Drive and half shafts and U-joints.

383vett

You need to isolate the source of the vibration. Does it happen when the engine hits 2 or 3 thousand rpm when the car is not moving. If so, it is from the engine or clutch/flywheel assembly. If it happends at freeway speeds, push the clutch in or put the tranny in neutral. If it is still there, it is from the drivetrain or wheel/tires. Check the wheel bearings for play, balance the wheels/tires, balance the driveshaft. The halfshafts are so short they are rarely the problem.

garys vette

I have reason to believe it may be a bent input shaft on the transmission. I allowed some inexperienced guys to put it back in a little while back and how they explained the way they did it has made me suspicious.

Thanks for the suggestions. I am going to do thse and report back my findings.

If it was an input shaft that would make it vibrate almost all the time. And have certain frequencies (RPM) it probably would be better and worse.

If it is in neutral the flywheel, PP, clutch, and input shaft are all spinning. When you push in the clutch the clutch and input shaft stop spinning correct. So If I find the worst RPM and push in the clutch keep RPM same that should tell me something.

We have been feeling a shudder in first gear on take off been doing it for awhile and way before rebuild. I refaced the flywheel thinking that would take care of it but it did not. It is a new clutch and new PP in fact went through two clutches and two pp and refaced the flywheel and still have the shutter. And replaced the TO bearing twice and pilot bearing.,

mtwoolford

Sorry to say this, but the time to rebalance the flywheel would have been before the engine assembly; i.e., pistons, rings, rods, bearing, crankshaft, flywheel (and pressure plate, optional) as a UNIT.

Soooo, as near as you can tell, is the flywheel the correct one for the application; 383 rotating assemblies are usually, but not always externally balance and if so, your flywheel should have a chunk of metal cast or bolted to it; if it was internally balanced, then not.

An 86, or any SB with a one piece rear seal is USUALLY (but not always if custom work was done to it) externally balanced.

cv67

Are the holes on your C beam wallowed out?
The pressure plate is still spinning wiht the flywheel being as its bolted to it

If the input shaft was bent id think it would be near impossible to shift

So its making the vibration without the car moving I take it?

garys vette

Zero balance outside Engine, But although I balanced flywheel did not balance assembly.



QUOTE=mtwoolford;1588543591]Sorry to say this, but the time to rebalance the flywheel would have been before the engine assembly; i.e., pistons, rings, rods, bearing, crankshaft, flywheel (and pressure plate, optional) as a UNIT.

Soooo, as near as you can tell, is the flywheel the correct one for the application; 383 rotating assemblies are usually, but not always externally balance and if so, your flywheel should have a chunk of metal cast or bolted to it; if it was internally balanced, then not.

An 86, or any SB with a one piece rear seal is USUALLY (but not always if custom work was done to it) externally balanced.[/QUOTE]

garys vette

Yes I
I realize PP is still spinning.

I can not remember did not google yet there is shaft in a shaft correct. If you are at speed and push clutch in (drive shaft spinning) is the shaft that is in PB spinning.

If the shaft was bent outside transmission only. I think it could vibrate but u could still shift OK.

C beam is good,

Still trying to determine when it is and is not vibrating.

garys vette

OK had a chance to drive it and do some more trouble shooting. I would say that almost all the vibration goes away when you push the clutch it at various speeds.

So the drive shaft has to be spinning if the clutch is in or out. So the question is what is not spinning when you push the clutch in versus it being out.

Any help would be appreciated.

Merry Christmas

86 4+3

MRPVette