Jump to content
SAU Community

Recommended Posts

After rebuilding my RB26 with the following specs I have spun a bearing on no 2 after 2000kms. All of the other bearings are also hammered - and I believe it may be due to a clearance issue.

Here are the specs:

Aries Pistons and rings (86.5mm)

std rods with ARP bolts

ACL Race series bearings

STD oil pump (start the flaming....) oil pressure = 20psi hot at idle up to 80psi odd at high revs (ie good oil pressure)

Trust baffled sump (insert type, not weld on)

Castrol 10W60 edge syn oil

2xoil coolers

external filter block

Tomei head oil restrictor

The engine ran strongly and made good power (high 300rwkws), the knock recorded (pwr fc) was always <35, AFR always logged and spot on via laptop and wideband.

They should be the related specs required - please ask if you require more info.

My engine was built with around 2.5 thou clearance on the rod bearings, although the factory spec as per the manual is 0.8 - 1.5 thou. I am wondering if the greater clearance of 2.5 thou has killed the bearings and what clearances people are using in similar built motors of the same horsepower.

I am looking for ideas from people with EXPERIENCE / and or ENGINE BUILDERS of 400rwkw RB26 engines here - please don't post if you don't know what you are on about!!

Any help is greatly appreciated, I really don't want this to happen again!!!!

Cheers,

Andrew

Blue32

Link to comment
https://www.sau.com.au/forums/topic/232242-rb26-rod-bearing-clearances/
Share on other sites

Mines no fire breather, but my big ends were set around 1-1.5 thou and the mains I set at 1 thou. I was bit worried that the mains could have been tight, but it was with in spec. I have since completed 30,000km plus.

My Vl turbo done some 100,000km and I set the mains closer to 2 thou and the mains similar I think.....

My first imression was that 2.5 thou sounds rather loose for an RB engine. Remember that NIZPRO run what are considered to be tight clearences, like 1-1.5 for both mains and big ends...

Other than contaminated oil (or surge), detonation and clearence issues bearings are generally issue free.

I totally sympathsize with you.

Andrew, you are fairly fast at Mallala and your engine failed at the track. Have you consider other causes especially oil surge with your setup?

What oil pump and oil cooler have you been using? What was your oil temperature when the engine failed?

With the amount of g force you are doing around Mallalla, the Trust baffle insert may not be enough if you have a high flow pump. I think a Trust sump extension kit will help your oil surge

Edited by 9krpm

i run 2 thou on a 420rwkw rb26, has made over 450rwkw on dyno and no dramas with bearings. Im using acl race series if that matters. Has been running for 8 months with no problems. I got this clearance reccomended to me by a well known rb26 specialist workshop so i trust them 100%

Edited by unique1
i run 2 thou on a 420rwkw rb26, has made over 450rwkw on dyno and no dramas with bearings. Im using acl race series if that matters. Has been running for 8 months with no problems. I got this clearance reccomended to me by a well known rb26 specialist workshop so i trust them 100%

What oil pump are you running? I am starting to believe I may have had an oil delivery problem.......as well as the large clearances

your clearances are not the problem, but your machine shop should have advised you on what to run. usually run larger clearance when revving engine harder, i agree that you might have starved it. also Castrol WTF. how did you measure these bearing clearances?

What oil pump are you running? I am starting to believe I may have had an oil delivery problem.......as well as the large clearances
What oil pump are you running? I am starting to believe I may have had an oil delivery problem.......as well as the large clearances

jun high volume oil pump, gets around 27psi at idle and 80psi or so at full rpm when warm, i rev to 8500rpm usually. I also run the same oil as well (castrol edge 10w60)

Edited by unique1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • 2001 BE5D Subaru Legacy B4 RSK (3rd gen) EJ208 (pink injector) Twin Turbo 280PS 5-speed manual Full time 4WD "RSK" grade which means all of the above LQC option which means stock rear spoiler  I got it primarily to export to someone outside Japan who was interested. These BE5 Legacy B4 RSKs are going through a bit of a resurgence right know in Japan as they are one of the few cars from the "turbo, manual, RWD/4WD, 280hp gentleman's agreement era" cars that don't require stupid money to purchase. Which for some people might be a good opportunity to get as a base for restoration. If I can't find anyone to purchase it I will certainly be doing that myself over the long term. Why? Because it's properly fast in stock form, handles well enough for a GT sedan, there's still enough aftermarket and (if you can wait a while) genuine part support to make it a restoration candidate (<-- that will only get worse over time so it's a case of do it now or choose get a BL5 4th Gen). Mechanically it's fine, has only 89,200kms on the odometer. The problem with this car is that the body and exterior trims are weathered from at least the last 10 years being parked outdoors. I'm the 3rd owner, the first owner was the one that had it for 14 years and barely drove it, had a low-speed front impact (which didn't damage anything behind the radiator support) and got it fixed and sold it. The 2nd owner put most of the kms on it and parked it outside for the last 10 years, hence the door rubbers have seen better days but if you overlook those cosmetic details, it presents pretty nicely. There is some minor rust on the LH rear wheel arch which I'll have looked at too at some stage.  Also as you'd expect from a car this age, the clear top coat is gone, leaving a satin finish on the roof.  Mechanically it's fine (as you would expect from a car with less than 100K kms) but the steering does feel slightly vague around the centre position at higher speeds. So first on the list is to get the steering rack bushes looked at. There's also the Lock button on the remote which doesn't work, but the Open button does.... it means that the anti-theft system thinks it's always open? It seems like if you open the car and don't start the engine within 3 mins or so the anti-theft kicks in again without any beeps or signals. So if you got to start it after that, it won't. You have to push the open button again. That's how I understand it anyway. Just a small irritation but not a big problem to sort out. There's only one mod, the Wangan SPL muffler. Just a tad louder than stock. It's a really good mod for those who don't want to wake the neighbours but still want to hear a more prominent unequal length header EJ20 sound. Anyway I hope to get all those things done eventually, that is unless someone wanted to import it to their country from Japan (where I live). I'm open for negotiations as I really would like a Skyline... but this will definitely suffice in the meantime 🙂 *Disclaimer: This is how I picked it up from the dealer, minus the stuff on the back seat. I haven't cleaned the engine bay or done a thorough exterior clean, aside from spray painting the wipers. 
    • Wow, even with the Audi logo centre caps. I love OEM wheel mismatches. 
    • Welcome!  Can't go wrong with a Stag.
    • Looks good. Nice height.
    • Hey all, a little help from the Stagea hive mind plz.. I'm days away from buying either a 2002 Stagea 250tRS AR-X Four, premium leather, power seats and all the old switches etc that go with it, or a 2002 Stagea 250tRS VR-X Four AERO, pov pack, cloth seats etc, with coil overs, sports zorst, comes with original zorst and suspension and parts. (I think I've got the models right?) Both are VQ25DET, have 160000kms, both straight no rust both with $2000+ in recent servicing receipts, both ride on aftermarket 18" rims. The Aero has a replaced turbo as well. I like the cool factor of the Aero car but the AR-X has never been modified. Neither have been driven hardly at all in the last 5 years. Any thoughts on which one or does it come down to personal preference? davemoto 
×
×
  • Create New...