Rb26 Spins Another Set Of Bearings

[6InlineTT]

Hi guys and girls,

After assembling my rb26 for the 2nd time now after bearing woes...she's gone again. Lasted maybe 20hours of run time. Mains are gone. I'd say it needs a line bore, and the crank is already 30' under so I'd need a new one.

My thoughts are this- have the block reconditioned, line bore, new crank and any machining necessary.

Or do I go n1 block and new crank? N1 block is the best part of $3000 and would require a bore to 86.5mm to suit my forged pistons.

Cost effectiveness? Do I just buy a 2.8stroker and sell my existing forged rotating assy or have my block machined and stay 2.6

Has anybody made this decision and could perhaps steer me in the right direction. I'd like to go 2.8 but it seems reasonably pricey, but if it's going to cost me an arm and a leg for machining the stock block+ new crank I'll go 2.8.

How much did machining cost you? What did u do? What would you consider next time?

Mods, rb26- billet n1 pump

- baffles

- head drain, restrictor

- trust oil cooler.

-forged 2.6

-264 hks cams and hks2540 lag king turbos.

[Piggaz]

You don't build a 2.6, it's a pointless exercise IMO. Put a stocker in it and run it. If you want more capacity and it's benefits then prepare for a very expensive exercise.

Of you do decide to do a stroker, I'd be finding out the reason why the two engines before hand failed. That or give the assembly job to someone who knows what they're doing. It wouldn't happen for just no reason and you don't want it to happen to an expensive 2.8 rotating assembly.

Get rid of those woeful turbos too.

[Hadouken]

Agreed. Run stock 2.6. Or buy piggaz monster motor

[6InlineTT]

Well I already have the forged rotating assy in the car. Not that it's needed at my power level, I bought the car with spun bearings, got crank straightened, checked clearances 1.5thou, crank runout. Plastiguage etc. no dice. I think I'll remove the motor, have a shop look over it and stay 2.6, maybe pick up some 2530s (the 2540s do nothing until 5500rpm.)

Did you suggest buying a secondhand short block when you said building a 2.6 is pointless??

I appreciate the feedback. Thank you

[Piggaz]

What I mean by building a 2.6 is a waste of time is this.

If you need a new crank, rods and pistons plus paying someone to screw it together and allllll the costs (oil and water pumps, gaskets blah blah) what's the difference in cost of going a bigger bottom end? The bigger bottom end will be a little more exxy, sure. But the end result is so much better. (Some would argue it doesn't sound as good or whatever they dribble on about but that's another debate).

Now, being low mounts (say 2530's or so) and say you cap power at 350 - 380 kw and not spin it to the moon (7000-7500 max rpm), why do you need to build it?

The lasts two attempts have failed. You would have been better off whacking a stocker in it, getting it tuned and away you go. Odds are it would have lasted ALOT longer and driven exactly the same (save for compression differences which wont make a night and day difference anyway)

[zebra]

I wouldn't be putting a 5k bottom end in a motor if everyone you have built so far has destroyed a crank in 20 hours

[6InlineTT]

Ahh okay, perhaps I find a stock long block. And swap my billet pump out. Would YOU go to the trouble of fresh bearings, fitting my oil restrictor and a decent headgasket? Or just run with it and stay under 380? After thinking about stroking and the costs I'm a little turned off by the idea.

[6InlineTT]

I've rebuilt it once, it was last done by a performance shop. Lasted a few weeks and died.

[Piggaz]

Of you find a good condition stock engine and then fit new bearings and rings, ain't you just rebuilding it?

Where are you located?

[6InlineTT]

Newcastle. If you think it would be fine then I'll just do the oil pump and drop it in. I guess I'm just scared of the (probably overstated) rb26 oiling issues. I guess there are plenty of stock rb26s without baffles, billet pumps, head drains and restrictors getting around, I have all that and an oil cooler and look where I am.

[SiR_RB]

FYI when I bought my first stock 33 gtr engine, we pulled the sump off to out tomei baffles in, so while it open we put new standard size bearings in for piece of mind, can be done but depends how far you want do go with a stocker

arp headstuds with stock gasket is a good idea if running over 20-22psi

[6InlineTT]

Yeah well it's probably an hours extra work for bearings. Can't hurt. Probably cheaper than a full strip down on my block. I'll make a few calls and see what costs will be. The new crank alone is $800+ I saw a long block go for $1000 this week on sau. Seems like good value to me

[Blackkers]

Nitto the r34 was making over 600kw from memory on the standard bottom end r34 engine before the oil pump went. If you get an r33 engine in good nick and fit headstuds it will probably last for years with heaps of boost dialled in

[6InlineTT]

I like how you said "my first engine"

[Blackkers]

Someone will buy your forged gear and oil pump it won't cost you much to change over

[6InlineTT]

Gtr700 had 580awkw on stock motor before they went wild with it. Only blew it up by accidentally downshifting and overevving. I have a billet n1 pump gear set so I'm sure I can make it work

[6InlineTT]

Any recommendations on how much spool rods and cp pistons go for second hand?

[MrStabby]

No warrantee on the shop build?

Any idea what caused the failure?

What oil were you using and how far up the dipstick was it filled to?

What was the driving conditions when it went? (track/dragstrip/street fang/street cruise, rpm)

[GTRPSI]

Sounds like the crap was not cleaned out of the oil lines and got to the bearings......

[HarrisRacing]

There's no doubt that oiling issues DO exist in these engines, but I agree they are case by case.

My engine (as received) had 5 spun crank mains and 2 rods as well. Also the crank was bent beyond repair and I'm not a fan of grinding cranks in high revving long cranks anyway so that was out.

That being said, I think these factory built engines with the "fit bearings to the OD of crank and ID of rod" style of sizing almost dictates a "tighter" tolerance than most builds. Tighter tolerance = less oil lossage out of the bearing surfaces, which equates to the ability to use a smaller oil pump. So after 90% of us rebuild with standard bearings or a little looser tolerance (from polishing burrs from crank, or in your case oversized), then I think the issue is that the factory oil pump starts to fall out of being able to supply the correct VOLUME of oil feeding the bearings (loose bearings need more flow). The head restrictor keeps you close to keeping volume on the crank by reducing what is going up to the head and of course all other baffles, etc, just keep oil to the bearings in general. If you had a continuing starvation problem on track, I would lean towards baffles, breathing, etc, but I think there was something up with the rebuilds (looser tolerances, crank not retaining straightness, etc).

That being said, I am a big fan of the larger oil pump volumes in these engines. But I'd also have to recommend: deeper sump, more oil separation, etc...because the bigger pumps will pump the pan dry on factory setups (at least the Tomei oil pump installation manual says this).

I don't know if the billet gears you have supply any additional flow, but I would be looking into a replacement with a higher flowing pump if doing a rebuild and DEFINITELY looking for a factory replacement crank.