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Top end knocking: Balance shaft bearings or bad lifter(s)?

Posted: Thu Apr 26, 2012 7:51 pm
by Alibi
Hi all, long time no post. I've been immersed in the world of Pontiac Fieros for the last 2-3 years. Anyway, I traded an extra Fiero for a 98 Grand Prix GT, NA motor. It has about 172k miles on it and I just replaced the upper and lower intake gaskets when it started making a rattling sound.

I've got the top end torn back apart and have taken all the lifters out. I do not see anything obvious, what should I look for and how do I test them for too much play?

Also, the balance shaft has some rotational play in it, just a couple degrees, but it does click and I can see the roller bearings towards the front cover of the motor. Are the bearings supposed to be exposed?

If the balance shaft bearings are bad, can the bearings be replaced with the motor in the car? I really really don't want to tear this engine out although I can if I have to.

Re: Top end knocking: Balance shaft bearings or bad lifter(s

Posted: Thu Apr 26, 2012 8:03 pm
by Alibi
Here is a link to a video that I found that describes my exact symptoms. It was from an resolved thread on another forum where one person suggested it was bad bearings but another said it was just normal timing chain slop.

http://i19.photobucket.com/albums/b198/ ... 1b0688.mp4

Re: Top end knocking: Balance shaft bearings or bad lifter(s

Posted: Thu Apr 26, 2012 9:20 pm
by Alibi
Looks like I can get a set of lifters and upper/lower radiator hoses from RockAuto for about $160 shipped. I don't really want to pay for new lifters if they aren't my problem though. Should I take them all apart and clean them, then put the car back together and see what happens?

Re: Top end knocking: Balance shaft bearings or bad lifter(s

Posted: Thu Apr 26, 2012 9:41 pm
by myfirstbonnie
The bearings are supposed to be open. They get lubricated from the splash of oil. If it was me, I would pull the front cover off (only a little more work) and inspect the timing set and damper. I would actually replace the timing set and while it was off, check the balance shaft for wobble and play.

As for the lifters, I would keep them soaked in oil and re-use them unless they look like they are all gummed up. Someone had a post on here awhile ago about taking them apart and cleaning them. They are a common lifter and I am sure Andrew would have a butt ton of them he could sell you if you do have a bad one.

Re: Top end knocking: Balance shaft bearings or bad lifter(s

Posted: Thu Apr 26, 2012 11:35 pm
by Alibi
I assume taking the front cover off involves removing the damper, right?

If I take all the lifters apart to clean them, what should I look for to determine if one is good or bad? If I have a bad one, what user name does "Andrew" go under in case I need to message him?

If I need to replace the rod bearings, can it be done by dropping the oil pan, plastiguaging, and just sticking in new ones?