Need Advice After Oil Pump Failure

[jarrod83]

Hey guys, had my forged rb30det running nicely for 5000kms or so afterwhich the internal gears of the oil pump decided to let go.

Unsure how long the engine was left running on the dyno with no pressure. The drained the oil had no chunks just a really fine silvery shine throug it, which is a worry considering the oil was changed the night before the dyno. I pulled the oil pump out and found quite a few small chunks of metal through the pump and on their way towards the oil filter.

What sort of damage do i have to look for to inspect the head??

I am planning to pull the sump off and replace the bearings and crank, pull the head off and completely dissemble that and give that a clean, as well as clean the block as best as i can. My main question is if its definately advisable to completely strip the engine and send it off to have a bath, i was planning to just run thru a few containers of shit oil at idle to clean it out, assuming the oil filter would remove any bits of metal?

I have been talking to a few people, who seem to think the engine was improperly balanced first time around, as my machine shop balanced the crank by taking weight of the flywheel and balancer. The balancer also had a bit of play on it on the crank which most likely contributed to the oil pump failure, not that spending most of its time redlined helped. So im getting the new crank balanced elsewhere with the new ross balancer and old flywheel. The pistons and rods are what im most confused about, the rods were measured to be within 1.5 grams of each other and the pistons were within a gram of each other. I was told that that was fine and the shop didnt balance them up, im now being told that for 8000rpms on a rb30 that this most likely needs improvement? Is there really much to be gained by completely dissembling them and getting them rebalanced?

Also if the pistons and rods are pulled out.. assuming the rings and bores are still in good condition, can they be re-installed without getting new rings and re-honing the block?? I'm not trying to be cheap, just trying to spend my limited time and money on where its needed most =P

Also trying to correct my excess oil to the head problem while the engine is apart, if you wanted to run a crankcase vent from the sump, where is the best place to connect the hose? im guessing it has to be above the level of the oil otherwise the air wouldnt travel up the hose?

Kind Regards

Jarrod

[TiTAN]

my whole bottom end was balanced to within 0.1 gram. when you start spinning things around at thousands of RPM the G forces make a little bit of a difference into a big difference.

[jarrod83]

Yeh definately, i was also thinking that the up and down bits would be more important than the round and round bits.. just wasn't sure on whats considered reasonably balanced

Jarrod

[blitzxtr]

blocks need to be properly cleaned, all oil gallery plugs need to be removed and brushed through. Oil restrictors need drilling out too and this is something that is rarely done. I watched my own engine block be cleaned, it took a total of 3 hours work before it was satisfactory.

45% of rebuilt engines prematurely fail due to contamination from a 'dirty' build. Clean it properly, keep it clean and your 1/2 way there to a sucessfull rebuild.

Edited August 9, 2010 by blitzxtr

[T04GTR]

what revs was done? also the rev limmiter will have a big efect on a oil pump failure.

this topic is a massive can of worms.

at a minimum you need FULL WEIGHT FLYWHEEL, ROSS OR ATI CRANK DAMPER, FULL FACE CRANK COLLAR AND A N1 OR BETTER OIL PUMP.+ a rotating assembly balance. within 1 gram is ok. bettter if posible.

if you have all of these things and it let go then there is a big problem.

[jarrod83]

the revv limiter was 7250-7300 with a power fc pro ignition cut type rev limiter..

At the time i had a series 2 r33 oil pump and standard rb25 harmonic balancer, i had a bit of troubles with the balancer with the keyway being a little flogged out.

Planning to get a new crank and balance it somewhere else, a Ross drift harmonic balancer and a nitto oil pump, going the pull the engine apart and get the pistons and rods balanced to a higher degree as well, should make it a lot stronger.

Also planning to get some drop in cams and springs this time while its apart.. anyone got any preference between tomei poncams 256s and the 256/264 HKS setup with adjustable cam gears.

Jarrod

[Duncan]

blocks need to be properly cleaned, all oil gallery plugs need to be removed and brushed through. Oil restrictors need drilling out too and this is something that is rarely done. I watched my own engine block be cleaned, it took a total of 3 hours work before it was satisfactory.

45% of rebuilt engines prematurely fail due to contamination from a 'dirty' build. Clean it properly, keep it clean and your 1/2 way there to a sucessfull rebuild.

totally agree Paul.

Jarrod, did they replace the water/oil heat exchanger at the oil filter and any oil coolers? Never re-use them after an engine dies.

In any case, this is a warranty issue right? something was clearly wrong in the maching or assembly. Hopefully you paid one shop for both so there is no fniger pointing about the failure.

New crank is a good idea, especially if the keyway was average in the first place, the old one would probably need undersize bearings too after

BTW don't worry too much about how long it ran without oil pressure. If the light comes on at high revs its already too late. Also, the oil pump failure is often the symptom, not the cause, the gears crack when they try and push metal through.

[jarrod83]

My first engine was the standard rb25, but it didnt break.. i tried relentlessly at 27 psi but gave up in the end, i built the rb30 myself but had all the machining done at a local machine shop. I'm not out to point fingers and blame anyone that helped me as its more than likely my fault.. which is part of the "fun" when your learning everything yourself from scratch.. i got a few big burnouts out of it.. so im glad i got that much

I've pretty much bit the bullet and decided to send the bottom end over east to get inspected to see what they think went wrong and to make sure it doesnt happen again, and to balance it properly this time and adapt some rb26 bearings for it.

So dont reuse the standard rb25 oil/water cooler?? i was thinking about buying a oil cooler anyway so i might just add it to the list.

Cheers for the input

Jarrod

[jarrod83]

And the pump didnt die on the dyno.. it was getting tuned on the dyno, but sending the knock sensors crazy, not being happy with it he took it off the dyno and was driving it back to the workshop.. and said on the way back it started to flicker around a bit then dropped to 0 as he got into the street, so it possibly got driven a little bit, i might chek the oil from my last couple of changes and the filters to see if they have any bits of metal in them.

Jarrod