Recently I did a heads/cam swap and installed a GM LT4 heavy duty timing set. Ever since I finished the mods after the engine heats up, it sounds kind of like I'm running a gear drive. Using a long blade screwdriver to listen, the majority of the noise comes from the opti. Couldn't hear it through the water pump or the timing cover. Since the original opti bearings were questionable , I figured that it was the opti bearings making noise and replaced it. I installed an electric water pump at the same time. After replacing the opti and pump, the noise is still present at the same volume. As was before if you raise the RPM by 100-200, the noise settles out and everything sounds nice and smoothe (even listening to the opti with the screwdriver). The question is, are the Lt4 hd sets noisy, am I getting ready to grind up the water pump drive gear (which is useless now), any other ideas??

Thanks Everyone

 

It's possible that the chain is rubbing on the timing cover. What year is the car?

 

Why didn't you remove the water pump's drive?

 

Many have claimed that the LT4 HD timing set is a bit more noisy than the stock set. I have it and have no noise like you are describing.

 

96Z28

 

I went back with the stock mechanical drive pump after the mods. Eventually I replaced the opti and decided to go with an electric pump. Sooo the drive gear was left in.

 

IMHO you are grinding the teeth on WP gear it will quit soon and you can repair the eng. Danny Mc

 

Some guys dont install the water pump drive mechanism correctly, and the gear lash is to tight. I think this comes from not seating the bearing completley.

I checked min very closely to ensure that the gears did not bind.

 

I never noticed any increase noise after the installation of the GM HD timing set. I think you need to look elsewhere for the culprit.

 

Thanks all When listening with the good old screwdriver, it DEFINITELY sounds like gear noise. I'm going to go ahead and pull out the water pump drive gear. Since I don't need it, it won't matter anyways. I just have to find something o plug the timing cover with.