5.0 Main Bearing Problems

[Procharged91lx]

I am basically overhauling a stock 5.0 shortblock right now. I took the block to the block to a local machine shop and they cleaned the block honed it and installed new cam bearings.

now the problem. I bought a new set of Clevite 77 STD. size main bearings. I used Plasti-gauge and with a the stock main cap bolts torqued to 65ft lbs. i could only get 0.002 where the Chiltons book calls for 0.004 to 0.024. the crank has never been turned and the block wasnt line bored. if you torque down 3 of the main caps the crank will barely turn.

Do i need to order a set of std bearings with lets say about 0.010 undersize?. Please give me your alls opinion. Thanks

 

[Hawkeye_306]

I would trust Clevite more than Plastigage. The difference between 0.002 and 0.004 is minuscule. I would not trust plastigage to even be that accurate.

If you were worried, try torquing the main caps down (while slowly turning the crank as you go) without plastigage. This will help seat the bearings more uniformly – whereas before you may have been high-centering on the plastigage. Then remove the main caps, and put plastigage in a few different locations, and re-torque the main caps (you would not turn the crank this time so not to foul up the plastigage). Take the average of the 2-3 locations. If they do not average out within spec, then maybe start getting concerned.

I am not an engine builder by trade, but I have built a few engines – so you can take my advice for what it is worth.

 

[PUNISHER RACING]

.002 is fine on the mains

 

[Procharged91lx]

im not worried about the 0.02 clearance i am concerned that the crank wont turn after torqed down..this is the same crank i took outta the block so is the main caps. i just replaced new bearings. also the thrust bearing on the rear cap looks to be just a fuzz to small to go on the cap...

 

[BlownFiveLiter]

You weren't trying to turn it with the plastigauge still on the journal, right? It would have a hell of a time that way.

 

[dcurtis]

You weren't trying to turn it with the plastigauge still on the journal, right? It would have a hell of a time that way.

And be sure to lube it.

 

[Procharged91lx]

no plastigauge in the journal and it was lubed really well...

 

[PUNISHER RACING]

what is your endplay? are you binding up on the thrust? if you are lubed and and have .002 of clearance you should spin. also its not gonna spin like its on roller bearings it will have some drag to it.

 

[rj95svt]

The thrust bearing goes in the center #3 main cap not the rear main like a chevy!!!

 

[Procharged91lx]

well hell no wonder it wont spin. thanks alot guys appreciate it.

 

[rj95svt]

Your welcome man! Feel free to ask more questions if needed. I would rather ask questions than mess something up.


Good luck with the build!

 

[BlownFiveLiter]

also the thrust bearing on the rear cap looks to be just a fuzz to small to go on the cap...

The thrust bearing goes in the center #3 main cap not the rear main like a chevy!!!

Good catch!

I guess I missed that before.

Let us know if you encounter any other issues.

 

[347HO]

What is your "runout" btw?

 

[Procharged91lx]

Good news, crank is within specs on oil clearances and spins like a charm, a buddy of mine came over and done his magic. hes an engine builder. now just wait for the AFR's and then about 12lbs of boost....

 

[vikingpower]

well hell no wonder it wont spin. thanks alot guys appreciate it.

you should always read up on what you're doing before you do it!

 

[Procharged91lx]

hey listen here man i didnt ask a smart ass question so i dont need a smart ass to come and leave a smart ass comment. got it?..read upon that before you type n e thing else...! thanks to the rest of ya, sorry we all cant be perfect and get it right the first time.

 

[PUNISHER RACING]

WOW ! good catch boys, lets go home!

 

[rj95svt]

I know someone else who did the same thing and he ended up selling everything real cheap only to find out the only thing wrong was he put the thrust bearing in the rear main. Needless to say he was sick because he didn't ask for any help.

 

[Fast63]

hey listen here man i didnt ask a smart ass question so i dont need a smart ass to come and leave a smart ass comment. got it?..read upon that before you type n e thing else...! thanks to the rest of ya, sorry we all cant be perfect and get it right the first time.

Calm down dude, vikingpower gave you good advice. Research and document before you do anything. Don't be mad just because he's right.

Reading up on something before we do it is something we ALL ignore at times, and 9 times out of 10 it ends up really screwing us over.