Vibration After Cam Replaced

I had the riveted cam gear come loose and after it was replaced, my engine has a pretty good vibration. My mechanic said that it was an 8 dowel crank but there were no markings indicating that the flywheel was balanced.

Is there anything other than the flywheel that could have introduced this new vibration? It is strongest at 2500-3000 and then eases up a bit at higher revs.

You can feel it through the pedal, seat and shifter.

Cole

DAMN !

If you can hear and feel the vibrations that acutely and you've had the engine up to those rpms you've probably already ruined the case.

Bad mounts and loose engine mounting bolts and all will add to the vibration issue, but since it seems to be rpm specific, you need to pull the engine, open the case and look at the bearings, crank surfaces, and saddles at least. Don't want to skimp here.

Luck,

TC

Before you pull the engine again, remove the fan belt, start it up and see if the vibration goes away between 2,500 - 3,000 rpm without the fan running.

You can probably run it for 5 minutes form a cold start without the fan, but no more, and that should give you time to figure out if it's the fan causing the vibration.

Don't be surprised at how fast it revs up without the fan turning!

Cole,
If you did NOT have this vibration BEFORE you replaced the cam, and NOW you have a Vibration WITH a NEW cam, Me thinks you need to give this problem back to your mechanic.
If you're the one that changed the cam, what's different between before and after cam change.
Greg

It sounds like flywheel and pressure plate balance also check if the pressure plate fit's tight in in the flywheel if pressure plate fit's loose it will throw off the balance, ran into this problem a few months ago with the sach pressure plates, the kennedy pressure plates index better. Roland

ALSO..... are you using dual carbs? If you are...and they are out of sync, it can feel like the engine is unbalanced.

Mike

Whoaa !!!!! all thes sugestions are spot on But i bet you will Pull the engine and MAKE sure the gland nut and clutch plate are right and tight.. My guess

You used the same crank and case. That should be fine Did he also put in a new bronze crank gear to match the cam gear That stuff should be right.

Only thing left is if he flipped a bearing wrong on the re assembly tha would mess up the crank and bearings these are the first things to check if it has to come back down..

Someone Boobed

Finally got the engine pulled, turned the flywheel 1/4 turn and the vibration is gone! Now it's marked.

Thanks for everyone's ideas and help.

Too Bad he didnt use an offset 8 dowell pattern,flywheel only goes on one way as two of the dowells are closer than the rest. I havent drilled a non-offset pattern since I played at Woodstock!

Or the new cam is going flat and you have a mis match in the combustion balance of all 4 cylinders.

Speed Bucket. Just curoius. Was your "played at Woodstock" just a metaphor for having done something a long time ago or did you actually play at Woodstock?

Troy, as the saying goes, if he can remember, he wasn't there.

Sorry Troy, it was a sorry excuse for a metaphor (no insult to the 600,000,000 who were there, or claim to have been). I don't believe any one was 8 doweling VW cranks when I was seven except maybe Gene Berg or the Lowry Bros, but like Woodstock I'm probably wrong about that too!

I did have Charlie Christian and Django Reinhardt on vinyl...till my wife sold them at a garage sale.