Hey all,

I just started the rebuild on my LS1 today, and I've already hit an impass. I opened up the box with the main bearings, put the top half in the block, put the ARP studs in, laid some Plastigage on the crank, and then I got stuck. The bottom half the of the bearings will not fit in the main caps. The little key, for starters, does not fit in the hole in the cap. Also, if it did fit the bearing would be off-center so much that it would actually extend beyond one side of the cap. The diameter of the bearing is also so large that it would take quite a crush to get it to fit in the cap.

When I ordered the bearings I asked for Clevite P series bearings for an LS1, but I failed to mention that I actually have an LS6 block. Could this be the cause of the issue? I would assume this except for the fact that the top half of the bearings seems to fit like a glove. Not only that, but the thrust bearing fit perfectly in the third main cap. The other four were a no-go, though.

In addition to this problem, I have some other questions (yes, I'm ignorant):

1) Are the bearings mated together, or does any top go with any bottom? I saw nothing to indicate that they were paired up.
2) Just to be sure, the main caps increase in number from the front to the back of the engine, right? Main cap number one goes in the front of the engine as I recall. (It's been a long time since I took this all apart.)
3) Is there any reason to lubricate behind the bearing? (i.e. between the bearing and the block or between the bearing and the cap)
4) The ARP stud instructions said to hand tighten them in the block. Does anyone disagree? I'm inclined to tighten them lightly (10ft-lbs or less) with a hex key.

Thanks in advance for all your help, guys. This is my first rebuild, and I am determined to do it myself. However, I'm still ignorant about a lot of it, so I'm just going to take it slow and ask any questions that come up on LS1tech before I move on. I don't think I could do it without this board.

 

Sounds to me like you might have a mismatched set. Can you snap a few pics? Im guessing that when they boxed the bearings from teh factory, the guy grabbed all the correct uppers and the incorrect cap sides. To the best of my knowledge, theres no difference between any of the ls1 based blocks and caps.

 

Here are some pics...

The upper bearing effortlessly snugged in place (and wouldn't allow my camera to focus):




The thrust bearing went in place without issue (both upper and lower):






However, here's a shot showing the tab not fitting in the slot on main cap #1. You can also see that the bearing is offset so that it extends beyond the side of the cap:




And, here you can see that the bearing is actually significantly wider than the cap. I think I could get it in there, but I'd have to beat it down or torque the caps down to crush it in:

 

Judging by the width, they certainly look incorrect to me. Theyre not even the same with as the block side half bearings. Id call whoever you bought these from and send them these pictures and see what they say.

EDIT: Actually, upon further inspection they do look to be the same width, but the key is still offset incorrectly, and it dosnt sound right if you think youd have to hammer or torque them in. They should press in by hand.

BTW, looks like the shop did a nice job with the hone, but clean out the cylinders with a rag and some spirits. Looks like theres still a few filings or some grit in the bores.

 

Thanks, Tony. I'll probably clean them out with lacquer thinner, blow 'em out with compressed air and then put some 50 weight oil on them before dropping the pistons in.

This sucks big time. Not only did I have this problem, but Mahle failed to send me the wrist pin wire locks.

Anyone have answers/suggestions on these?:

1) Are the bearings mated together, or does any top go with any bottom? I saw nothing to indicate that they were paired up.
2) Just to be sure, the main caps increase in number from the front to the back of the engine, right? Main cap number one goes in the front of the engine as I recall. (It's been a long time since I took this all apart.)
3) Is there any reason to lubricate behind the bearing? (i.e. between the bearing and the block or between the bearing and the cap)
4) The ARP stud instructions said to hand tighten them in the block. Does anyone disagree? I'm inclined to tighten them lightly (10ft-lbs or less) with a hex key.

 

1. I dont recall anything stating that they are mated... All the notches / keys are in the same place on all the cap sections, right? I believe the rod bearings are the only ones you have to watch out for which way theyre installed since only the bobweight side will have a chamfer.

2. Theyre numbered right? I believe 1 goes up front but im not 100% positive. The front 4 should point the same direction, while the back one points the opposite direction. Hopefully you can figure out wether 1 or 5 is the backwards one.

3. I dont believe so. Just use assembly lube on the bearing surfaces and arp molylube under the bolt head / flange.

4. I dont think youll hurt anything by snugging them in a little... Maybe think in inch pounds rather than foot pounds. Its a similar idea to head studs.

 

3) There is no reason to lube behind the bearing. It should be completely clean.
Also as GuitsBoy said clean the block before any assembly. I would clean it with hot soapy water and white lint free rags . Keep cleaning untile your rags stay clean after wiping the components. You can always oil everything down after you clean it . Just make sure you are in a dust free environment. Keep it in a garbage bag while you are not working on it.
1) Bearings are not generaly mated but consult the manufacturer.