Main Cap question

[evltwins]

Ok, so my engine builder in infinite wisdom put the number 5 main cap on bass-ackward. Can I simply take that one cap off and turn it around? What about the bearing? Does it need to be flip flopped in the cap back to where it is oriented at now?

Thanks fellas

[Upgrade]

That sucks
Bearings are keyed so they don't spin.
And nothing says that the caps are 100% centered and fit perfect both ways.

[racer7088]

Ok, so my engine builder in infinite wisdom put the number 5 main cap on bass-ackward. Can I simply take that one cap off and turn it around? What about the bearing? Does it need to be flip flopped in the cap back to where it is oriented at now?

Thanks fellas

Yes you can turn it around. Shouldn't matter on number 5 which way the bearing is tanged in.

[evltwins]

I dont mean to be rude Eric, but "shouldnt matter" isnt an answer I need at the moment. Last thing I need is to get this all back together and spin a bearing. Im calling the shop when they open.

[racer7088]

The bearings only have a tang for fore/aft location and are not directional (except on FM thrust bearings) so it doesn't matter at all as long as the main cap is on correctly.

Fed Mogul thrust bearings are directional so # 3 cap does matter but there is only one set of tangs on that cap so if it is on correctly you can't mess that up.

On the LSx the bearings actually have the tangs on opposite sides though instead of together which is why people often put the caps on backwards.

Why do you think that cap is on wrong in the first place? Maybe it isn't?

You know #5 main cap when it is on correctly has the cap number reversed as compared to the other 1-4 main caps.

Sounds like you need a new shop though if these guys can't even put caps on the right direction or didn't pay attention taking them off initially.

[racer7088]

Also evltwins if this place line honed your block with the #5 main cap on backwards you are in a bit of a pickle as now you are stuck having to run it backwards or it may be screwed.

The LSx mains caps are pretty symmetrical but some are not enough to be able to switch the caps and run them backwards.

We fix crap like this from mickey mouse normal shops every week and if the block had shifted caps and they line honed it backwards you may have issues.

We have a 6.0 right now that had all the middle caps reversed since it had no numbers and the shop people there were morons and it is toast.

Maybe someone has some larger OD main bearing set now or coming out soon where this can be fixed as SBC and BBC do but then you are stuck with whatever bearings and clearances you have.

[evltwins]

F**K!! I found out it was on backwards when I went to install the rear cover and it obviously wouldnt go on. I def need a new machine shop. I think this is the first LS2 they have built. They ordered an LS1 timing set. Im just glad they showed it to me before putting it on and I caught it

If it wasnt honed, can I simply switch the #5 around? The engine didnt throw a bearing or anything. I know they polished up the stock crank and reused it and studded the mains

Thanks for your help Eric

[megadeth_guy01]

F**K!! I found out it was on backwards when I went to install the rear cover and it obviously wouldnt go on. I def need a new machine shop. I think this is the first LS2 they have built. They ordered an LS1 timing set. Im just glad they showed it to me before putting it on and I caught it

If it wasnt honed, can I simply switch the #5 around? The engine didnt throw a bearing or anything. I know they polished up the stock crank and reused it and studded the mains

Thanks for your help Eric

You better hope they line honed it if they put main studs in it....

[Upgrade]

just to clarify now that I'm less tired...
The tangs alone don't stop spin. The fit to the bore/ friction are the big factors.


I guess "that sucks" was an understatement.
I'm glad I decided to let Eric build my TT LS rather than let my excellent machinist learn on my stuff and maybe miss something that's not done on a earlier gm engine.

[racer7088]

F**K!! I found out it was on backwards when I went to install the rear cover and it obviously wouldnt go on. I def need a new machine shop. I think this is the first LS2 they have built. They ordered an LS1 timing set. Im just glad they showed it to me before putting it on and I caught it

If it wasnt honed, can I simply switch the #5 around? The engine didnt throw a bearing or anything. I know they polished up the stock crank and reused it and studded the mains

Thanks for your help Eric

Yes if it wasn't line honed with the rear cap on backwards you can switch it around no problem.

The #5 cap has tangs on both sides and you could use either one actually but if you want it like the factory does it the tangs need to be reversed from the block side.