timing chain, crankshaft bearings, rod bearings [Archive] - GrandAmGT.com Forum


View Full Version : timing chain, crankshaft bearings, rod bearings

09-04-2007, 11:57 AM
This carries over from http://www.grandamgt.com/forum/showthread.php?t=70048&page=2

I have low oil pressure when idling and have a nasty knocking sound at all RPMs.

I've decided I'm going to replace my main bearings, rod bearings, timing chain and oil pump.

Here's the part list i've accumulated so far:

$12 oil pump screen
$15 rod bearing set
$40 timing chain
$20 main bearing set
$55 oil pump


1. Should I also get the crank and cam sprockets for the timing chain change or are they generally not necessary? (assuming they look ok when I'm in there)

2. Should I replace the cam bearings?

3. The haynes expects you to have disassembled the entire top end down do the block and have removed the pistons and rods before you pull out the crankshaft. Does anyone see a problem with removing the crankshaft with all of that still intact ? (i would obviously disconnected the rods though.)

4. Also, is it possible to change the crank and rod bearings without completely removing the crank?

5. Anyone foresee any problems with what i've stated?

09-04-2007, 12:21 PM
The crank has to be properly prepped before putting in new bearings and considering you already have an oil pressure issue, I would say machine work probably will be necessary. I also wouldn't touch the cam bearings. They take a special tool for installation and removal. Your machine shop can do this for you if you don't have the tool or know-how to use it.

Since this is your first time inside an engine doing major work I would disassemble everything and just overhaul the engine. Trying to cut corners here will lead to disappointment and more money spent next year when you take the engine out again due to the knock returning. But before doing that please get a few engine overhaul manuals and read them completely from cover to cover. The Haynes manual is not the best source for how to overhaul an engine for beginners. It takes into account that you already have a basic knowledge of what everything is and where it goes. But judging from your posts, you don't even know that.

09-04-2007, 01:02 PM
Roughly two years ago I changed the head gasket on my own without trouble.

I'm hoping to be able to just swap the bearings out and have it be done. I know what everything inside is and what it does. I know the very basics of an overhaul procedure, though I'm not exactly looking to overhaul it. I don't want to have to check widths and measuements all day. All I really want to do is take it apart, put new bearings on and put it back together. I'm not looking for worst-case scenarios; I'm more interested in average case. Such as would you say 70% -80% of the time if someone were to just swap out the bearings then everything would continue to run fine for a couple years?

I only use the car to haul things and as my winter beater since my Z is utterly worthless for those things.

09-04-2007, 01:24 PM
If you don't take the crank out and check the dimensions on it, then you might as well throw your money away. New bearings alone, won't fix your problem and make it last for a couple years. Hell it may not work at all, due to all the metal flowing through the engine.

09-04-2007, 01:27 PM
That's a bit of a bummer. How much should I expect to pay a machine shop to true it up?

09-04-2007, 10:27 PM
Get a used engine from a JY. It'll be cheaper.

09-04-2007, 11:11 PM
Get a used engine from a JY. It'll be cheaper.

with intentions of dropping the whole engine into my car, or pulling out the crank and just using that?

09-04-2007, 11:16 PM
Use the whole engine. Used 3400's with low mileage are pretty cheap and easy to get.

09-04-2007, 11:34 PM
Aye. Use the whole engine. You can re-gasket it out of the car if you like. I'd reccomend at least doing the LIM gaskets with it on a stand to save future heartache.

09-06-2007, 12:41 AM
sounds like a good plan. I'll let you know the prices I find later on.