Big End and Main Bearing Size

[CruiseGTi-R]

My crank has only been polished and the block mains haven’t been line-bored either, so my engine builder and the machinist said that ‘standard bearing size’ will fit fine.

I am, as usual, sceptical. Looking in the Nissan manual, there are all sorts of different grades (thicknesses?) of bearings just for ‘standard’ size depending on the markings on the crank and block.

So, IF I was ordering standard size bearings from Nissan I could probably get the right ones, but I’m using ACL bearings, which only have the one ‘standard size’ so will these be the right size???

Given that it failed on the big end last time, I should spend some effort getting it right :-D .

 

[stumo]

If ACL only make one standard size then that's the one you'll have to use.

If you want to use the Nissan bearing you'll have to find the numbers on the block and crank and order the correct bearings.

there's a diagram on here somewhere telling you what you need to work out the numbers.

 

[CruiseGTi-R]

Its that which I'm worried about. If you need to go to the lengths described in the manual to get the right grade Nissan OE bearings, then how can the standard ACL ones be the exact right size???

 

[jpward]

Guy that done my crank ground the crank to match the bearing sizes taking into account clearance i dont know for sure but i would have thought that was the correct way to re-grind any crank?

He should also spec the bearings needed get him to look here and tell you if they will do;
http://www.aclperformance.com.au/NissanSR20DETBearings.htm

Then its his call if they are not right
;-)

 

[pulsarboby]

im in the same boat as toby, and have just fitted a set of acl bearings today with just a polished crank!
if the crank is within spec as it will be, then those bearings will be fine mate.
think you are looking too deeply into it.

providing the engine turns over freely by hand, with no tight spots then it will be fine

 

[frit]

Its that which I'm worried about. If you need to go to the lengths described in the manual to get the right grade Nissan OE bearings, then how can the standard ACL ones be the exact right size???

Old thread I know but relevent to me so ive resurrected, I have the same worry as above and plus the person i bought the engine from, which im using the crank from, said he had trouble with ACLs being too tight and so went for Nissans instead. I only really want the ACLs because of the name, is there any other real benefit or anyone know if Nissan bearings are good for 350-400hp?

 

[stumo]

The Nissan bearings will be fine....see the thread on the mongifiers.

 

[zer099]

I have a question in the same ball park:

I just installed some ACL Mains, Thrusts, and Cap bearings. Before tightening down I check for clearance (perfect) and that everything rotated easily (which it did with ease and as if floating on air). Then I tightened the mains down to spec: 38Nm then ~100Nm. Went to check everything spins freely and it has become a solid piece of the block (i.e.: would not spin for the life of me). Loosened everything up and check it for ease rotation and it once again spins freely as before. Tightened it back down to 38Nm then went for the minimum of 84Nm. Check for spin again, and it spins super easy, as it did when not tightened; BUT, it takes some effort to get it started. Once you put about 65Nm on it she spins right as rain. She even spins easy after that unless you let her sit for about 5 minutes, then it takes a little mussel again to get her spinning easy again.

Crank is in great shape. Just had it cleaned and polished, and I'm using the standard size ACL bearings.

Thoughts? Is that okay? I'm not too worried about it only being tightened to 84Nm seeing that's still more then the max on your standard SR, but this is my first time fully assembling a bottom end of a non-diesel engine so I'm not sure how it should feel. Oh, and the assembly lube I'm using is a moly lube (please save the “OMG are you crazy” comments) which is thicker than a Lithium grease so that could be it as well. And lastly, the main bearing grades are 44334.

 

[zer099]

UPDATE: Fixed. My dumb self had the main caps in in reverse order. Switched them around and she spins free now with just a hair more weight than the wrench on the crank with the mains torqued at the max 114Nm.