driveshaft has a slight wobble
02-04-2016, 03:13 PM
#21
Racer
Woops, missread it. I thought you meant at the rear of the driveshaft. I guess since the shaft felt so solid in the torque tube (no side to side play) I figured that pilot bearing wasn't much of any additional support. Everything is probably ok and I'm just nit picking. I'll get the pilot bearing replaced this weekend and hopefully that helps.
If your bearings have no play, and your rubber couplings are in good shape, your propshaft/TT is probably good. Plus, you said when you rev the engine, sitting still, in neutral, with the clutch IN (disengaged) that you still have vibrations. That isolates the engine/clutch assy, as the propshaft is not spinning.
Your original FW and PP will only go together in one orientation. The two locating dowel pins are 170° apart, so they can only be clocked one way. Bolt them together and have a GOOD machine shop tell you what the balance/unbalance of that combo is. This will give you a good head start. If you want to keep your factory balance, and I don't know who would NOT, then the new assembly should match the original assembly. That way your are "putting back on" the same thing as what you "took off". Like you took off your original assembly and put it right back on. It's as simple as that. Now, if you didn't mark/index somehow the original FW's orientation to the crank.....
Usually the "7th" holes line up, but not always. That's a good reference point to start though.
You are in the best possible position to fix this by having your stock stuff, IF it is only a balance related issue.
GOOD LUCK!!! (ok, I shouted that time
)
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01silvercoupe (02-04-2016)
02-05-2016, 08:56 AM
#22
The input shaft wobbles? To me, it seems rather pointless to check for runout when the one of the bearings that supports the shaft is missing. The input shaft is supported by the throwout bearing in the front and a single roller bearing in the rear. A single roller bearing itself won't hold the shaft straight and a rubber coupler has little chance of holding it straight either.
you are absolutely correct you can not check the run out on the input shaft with it in the tube. To check for straightness you have to remove the input and put it in a lathe. We get this phone call often that a input shaft on the torque tube is bent however 99% of the time after explaining that it only has support on one side and the rubber coupler is not true the check it in a lathe and they are straight.
02-05-2016, 01:32 PM
#23
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St. Jude Donor '08
Hey Bill,
CHECK THIS OUT.
https://www.corvetteforum.com/forums...ndbuilt-2.html
post #26 is a video of the hand build LT4 and LS7, current procedure.
timestamp 8:56 shows the hot balance, and balance weights. Notice the entire engine ins in the balance stand, WITH BOTH the flywheel and pressure plate installed.
Yet, there will still be people who won't believe it is done.
CHECK THIS OUT.
https://www.corvetteforum.com/forums...ndbuilt-2.html
post #26 is a video of the hand build LT4 and LS7, current procedure.
timestamp 8:56 shows the hot balance, and balance weights. Notice the entire engine ins in the balance stand, WITH BOTH the flywheel and pressure plate installed.
Yet, there will still be people who won't believe it is done.
Thanks
Bill
02-22-2016, 09:23 PM
#24
Follow up
Just a follow up post. Replaced rear cover gasket, rear main seal and pilot bearing. Revs nice and smooth again. The old pilot bearing had some damage to the bearings and some scaring on the face.
Last edited by 01silvercoupe; 02-22-2016 at 09:24 PM.