What keeps causing bearings to fail? My motor is an b18c 84mm turbo charged motor, all bearings are within specs, rebuilt it twice but keep having bearings go out. Any ideas on what the main cause of bearing failures are? I'm using 15w 50 mobile oil, and I throw in an new oil pump everytime
Block specs:
JE 9.1 84mm pistons
crower rod
oem bearings

 

I had problem last year with stock bearings. 16-25 passes and they were shot. went to Calico coated bearings and no more problem. they coat the skirts of the pistons, there's big advantiges there. call them 704-483-2202

 

So Calico is an brand of bearings or are you saying Calico does the coatings on OEM's..? Thanks for your input I'lll call them for info..Any ideas would help cause I'm having to many problems w/ these bearings. I know theres more ideas out there c'mon, help an fellow racer out here..

 

I think the problem goes deeper than some coated bearings. The surfaces shouldn't even be touching, there is a layer of oil in between. I don't see how coating would help. My .02.

 

So your saying maybe tolerance is to tight?? I just wanna know what works for all you racers?. Not that it matters but this is an all drag car, I say that 'cause street cars do have the problem too. Theres more than a couple draggers in here, Whats up? And back to the issue what causes it and the solution for it. I;m willing to try anything that sounds reasonable even if it breaks my wallet. We all know how much these motors cost!!

 

Are the bearing spinning or just getting wore down? Too much timing and/or detonation can cause the upper half of the bearing to wear. Got any pics of the bad bearings?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B20T CRX &raquo;</TD></TR><TR><TD CLASS="quote">Are the bearing spinning or just getting wore down? Too much timing and/or detonation can cause the upper half of the bearing to wear. Got any pics of the bad bearings?</TD></TR></TABLE>

sounds like a clearance problem to me

 

I will post pics up as soon as i can, just so yall get a clearer picture about this.

 

So is all clearance should be within stock specs or does everyone has their own specs, since using OEM bearings staying with stock seems logical to me. Unless theres someting else Im missing?

 

Couple ideas....Dirty block----Have it water blasted
Clearances too tight-----Use larger clearances, I know I do on my race motors.
Check for detonation maybe ...check crank etc...make sure everything is balanced.

 

BTW... I have used ACL bearings and had great luck with them.

 

I've called my engine builder and was told that the clearences he use are around .0018 and .0020. Is that too tight? What are the clearances that you turbo guys spec to?

 

Are you talking main bearings or rod bearings or both? I would look to micropolishing the crank shaft and perhaps having the big end of the rods checked to see if they are out of round.

 

Hey Earl, I was talking about the rod bearings, mains seems to be ok. So is that good or bad .0018-.0020 on the rods???? Thats something to look into (micropolishing). I'm just sick of paying thousands of dollars month after month and things still go wrong, sometimes I feel like when their building your motors that dont take that extra effort to build it like it was theirs. Dont get me wrong, they know their stuff, I been trying to build this car for many years now and cant get it no where. I'm not the only one.
Earl I heard a lot of good things but benson blocks maybe I should ditch my guy and have built by benson?...

 

^^^^^^^^ Good idea.

 

question, what causes excessive main bearing wear on the crank pulley side? ive pulled apart 2 motors, all the bearings are mint except the one on the end where the crank pulley is, that bearing shows significantly more wear than the other bearings

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sp00n’d Supra &raquo;</TD></TR><TR><TD CLASS="quote">question, what causes excessive main bearing wear on the crank pulley side? ive pulled apart 2 motors, all the bearings are mint except the one on the end where the crank pulley is, that bearing shows significantly more wear than the other bearings</TD></TR></TABLE>

either too much drive/timing belt tension or an out of balance pulley

 

or a bent snout

 

.0018"-.020" should be OK.
Calico takes ACL bearings and coats them. I tried a few sets but were not that impressed with them. Sounds like others have had better luck with them. One thing to remember is that when they are coated, it drops your oil clearance quite a bit. If you keep losing rod bearings, it could very well be the finish on the rod journal. It has to be perfect and perfectly round or you can lose a bearing in a few months. If it happens again, I think I would just replace the crank.

 

About the bearings, this is the second time it happened, Imay have to replace the crank. This motor is an B18c is it ok to go with an LS crank. How will it effect the performance. And does it need new LS rods because its an LS crank?

 

You will need LS rods since your using an LS crank.

As stated above. If you are getting a lot of detonation then the rod bearings will show signs of it by failing. Look further into your problem than just what lies in front of you.

 

If detonation is causing the bearings to go. Why is the pistons in such good shape? I'm not saying that your wrong cause any info is just gonna help me and others out, is just leaning towards an more mechanical problem than an tunning issue . And yet I could be all the above! Thanks for your input.

 

Its definetly possible that there is no damage on the piston itself from detonation. Detonation over time will hurt the rod bearings, slight detonation over time may not damage the pistons themselves.....obviously major detonation will.
I would look into having a machine shop look at the big end of the rod to check for out of roundness. I had a set of crower billets that I spun a rod bearing on and took it to my machine shop, he had to purchase a new mandrel to refinish the bore but they came out looking great and bearings fit like new again.

 

I'm gonna have them checked out. What about the crank, is it still usable after it spun the bearings on it?

 

If you did spin a bearing usually the crank is toasted. They are repairable, but for the most part it cost more to have it repaired then to find a used good one. If there are scratches you might get away with a micro polish on it, but if its gouged then forget about it.