have you dissassembled the pump and checked for wear/damage/trapped particulates?
are you running an oil cooler?

i run in all of the motors i build on the cheapest non-detergent 30wt i can find...then run synthetic 10w40 during the summer an 10w30 during the winter, but thats based on bearing clearances.

I did the first time I built it and it looked fine. My oil pressure at the sandwhich plate has been rock solid though so I do not believe it is a pump issue. No oil cooler.

Yeah I would have liked to switch to the 0w30 which like i said is more of a 0w40 but I have my doubts if that would have made any difference at all.

you should disassemble it and inspect for damage anyways...especially since you've been having issues that point to oiling problems.

Is there any other head related issues you can think of that would contribute to the failure of the bearings? It seems like after I put the RB26 head on shes gone south on me bad.

Well I have no choice now but to pull it apart unless I don't mind a hole in the side of my engine. I'd just like to know what the hell is the issue before I rebuild it, have it crap out, and 100 km again and I'm in this same spot for a third time :/. It drives me nuts when I can't figure out what the problem is like this.

the crank needs to be checked for straightness, take it apart and go from there...

the connecting rods should also be checked... and they may need to be honed due to being out of round... do they have ARP hardware?

what was your bearing clearance for the mains and the rods

Ninja edit : also when you plastiguaged everything.... where all the parts being measure stored/kept in the same place? like the crank wasnt in the house and the rods in the garage etc.. the tempature differences can make a difference if there extreme enough when using platiguage... or any other method for that matter

Is there any remote chance that a failed PCV system could cause this? I have a suspicion that it is not working properly. I hvae the stock pcv system but with a really long hose to the intake, and maybe the PCV valve is not functioning correctly.

Just spitballing, but if your crank case becomes pressurized at idle or whenever, whatever it pressures up to, would be subtracted from your oil pressure near the bearings correct?

Edit: No wait that doesnt make sense, the sump is part of the thing being pressured up , therefore no differential.

i say some trash is in the oil galleys some where or the pump is bad.

are you ever going to check what was suggested?

Dont take this the wrong way, but judging what you have posted in your last post, i dont think you should be assembling engines clearly there are some things you don't understand. Which is fine, we all start somewhere, but i think your in over your head and should have someone else with more experience lend a hand in the next rebuild.

Carl H wrote:i say some trash is in the oil galleys some where or the pump is bad.

I'll definately let you know what I find. I just got back home and ran out of time tonight. I think the pump is ok, because I have good pressure, but I'm going to disassemble it anyway.

RRRRB wrote:are you ever going to check what was suggested?

Dont take this the wrong way, but judging what you have posted in your last post, i dont think you should be assembling engines clearly there are some things you don't understand. Which is fine, we all start somewhere, but i think your in over your head and should have someone else with more experience lend a hand in the next rebuild.

Yes, when I get around to it. What is wrong about my above post? That excessive blowby can't ruin bearings?

http://www.advantageengineparts.com/pdf ... ailure.pdf

We'll you're certainly entitled to your own opinion. I've rebuilt engines ranging from dirt bikes, atvs and now I'm trying this RB30. I also had this engine running for two seasons with an absolute thrashing on it last season filled with racing... After I rebuilt it myself. I'm also a mechanical engineer who designs downhole oilfield tools for a living. The application of the concepts of tolerances and clearances in the thousandths is what I get paid to do. So I strongly disagree with you when you say I'm in over my head. But yes I'm still learning about building engines.

When I get the engine apart, I'll take some pics of my findings and then maybe you can help me out with anything you see.

Your theory isnt accurate... the link you provided does indicate blow by as a possible cause..(just not in your case) but in order for that to cause bearing failure, the engine oil would be extremely contaminated with fuel and combustion contaminates.. you would notice this problem in an application like yours... and im sure you change oil.. the lack of lubrication and badly contaminated oil would cause the bearing failure... this would take quite a while to do.. and happen over time on something completly worn out, which isnt your case..

There is more to assembling an engine than clearances... im sure you can read a mic and plasticguage etc.. however there is more to it than that..

If you dont check what has been suggested to you then your asking for it.. Just make sure you "get around" to having these things checked out before you deceided to throw in another set of bearings..

Hows the crank pulley... has this engine ever been balanced?

Oil cooler equipped?

Pulled this thing apart finally.

I don't know what to think. I found a ton of ARP Ultra torque in the mains feeds; this s*** is meant to be used on engine internals, isn't it? It was literally piled up in the main journal feed hole in a few of the mains. I used it on the head studs, mains, and big end nuts. You'd think the filter would catch it. I didn't change the oil since I rebuilt it so it would have been floating around in the oil for awhile (~400 km?). A few big ends look kinda burned too. But again there's hardly any damage to the crank really. This thing sure likes to give me advanced warning when something is wrong.

I checked the runout and its .0018, almost at the limit of .002.

Idk, I might just try again sans ultra torque. I really can't afford to go forged with it at this point

Here's a pic of the worst main for your viewing pleasure:

arp used to state that you could use it as bearing lube but have since retracted that statement...i'd pull it all apart and pop out the main oil galley plugs in the block and rifle brush it clean as well as remove the plugs in the crank and clean the oil journals thru the crank with pipe cleaners and use setscrews to seal it back up.

ST240 wrote:Pulled this thing apart finally.

I don't know what to think. I found a ton of ARP Ultra torque in the mains feeds; this s*** is meant to be used on engine internals, isn't it? It was literally piled up in the main journal feed hole in a few of the mains. I used it on the head studs, mains, and big end nuts. You'd think the filter would catch it. I didn't change the oil since I rebuilt it so it would have been floating around in the oil for awhile (~400 km?). A few big ends look kinda burned too. But again there's hardly any damage to the crank really. This thing sure likes to give me advanced warning when something is wrong.

I checked the runout and its .0018, almost at the limit of .002.

Idk, I might just try again sans ultra torque. I really can't afford to go forged with it at this point

Here's a pic of the worst main for your viewing pleasure:

i know this is old but ive went thru this alot with my rb30 build and i found out the hard way but with the 26head what head studs are you using? i am using the rb25 head studs and the issue i had was some of the cramping pressure was not there even tho it was a** tight as it could be so i had to use washers to get this corrected. since then i havent had a spun bearing. just my 2cents

why would a bearing spin due to different head studs?
rob at RIPS uses 25 studs in almost all their 'normal' motors...

Carl H wrote:why would a bearing spin due to different head studs?
rob at RIPS uses 25 studs in almost all their 'normal' motors...

well in my case, it casued the head to lift when under pressure which was not able to return easily like it should and im pretty sure the holes werent aligned when the head moved. but thats my issue. i still use rb25 head studs as well but theres always that little detail that some people forget to tell you and i had to figure it out the hard way, and it also caused alot of blow by to.