1800 RPM vibration?

z28krazy · 01-09-2007, 06:18 PM

A friend of mine has just replaced the crank sprocket, cam sprocket and roller chain on his 98 LS1 Camaro after 130k miles. He used all GM factory parts and gaskets for this job.

It now has an annoying engine vibration at 1800 - 2000 rpm.

The Chevrolet dealer parts man and the factory say the sprockets are the right ones for this engine and suggests that the harmonic balancer be checked.

He re-used the old balancer, which does not have a key to locate it on the crank snout, and inspection doesn't show any counter weights or drilled holes to indicate that it has been or needs to be balanced.

He also installed a new water pump at the same time as the timing chain swap. We plan on testing the balance of the water pump by removing the drive belt and running the engine.

Has anyone run into this problem?

Would rotating the balancer on the crank make a difference?

**jambofla** · 01-17-2007, 04:25 PM

I have recently removed the balancer from my 2001 LS6 without knowing that there was no key way for alignment. The Chevy Tech line is looking to see if there is a way to realign the balancer in the original position without going through pulling the motor for a trip to a shop for rotational balancing. They told me that you are supposed to score the crank and the balancer to insure that they are reinstalled in the same position. If you read further there are some people that have been nstalling under drive pulleys with no balancers. Some people are having bearing problems and some are not. I guess it is the luck of the draw as far as getting the position correct. Wish I had known ahead of time but...
Good luck and I will let you know if I find out a simple method from GM

z28krazy · 01-21-2007, 03:51 PM

Bearing problems. I sure hope that the HB isn't the culprit doing that!

**jambofla** · 02-15-2007, 03:07 PM

Latest info from local Dealership. Find an LS1 or LS6 that you can rotate to TDC. (Remove #1 plug and rotate motor until piston is at the top of compression stroke, hold your finger over the spark plug hole tightly until you don't feel anything coming out). Use a digital camera to photograph the position of the balancer on the motor that you ran up to TDC. Run your motor up to TDC and install balancer in the same position as the other. Pretty high tech huh? I guess it is better than nothing.