The Oil Pump Stuffed It

[druzilla32]

we found out why my rb26 died, it wasnt from too much boost like we first thought.

this is the side of one of the pistons:

scratched up pretty bad

and we think this was the problem:

perhaps in japan they upgraded the pump but used the standard crank.

so for the other guys building there rb26's, if your going to upgrade to an N1 oil pump, you might want to get a 33gtr crank, or atleast get the standard one built up so the driver is longer

[Cubes]

Thats not the problem.

The problem occurs when they actually crack.

Open up the oil pump and inspect the internal gear.

I've seen a few pumps that are fine but have a little wear on the drive gear. Unless the wear is so extreme the crank drive spins without touching the oil pump drive, in your case this is not the case.

[Gav]

A well known problem (or it should be!) that needs to be re-iterated from time to time.

Your piccys show the issue of the early RB26 cranks clearly - well done.

For those "leaning hard" on early model GT-Rs; take heed.

[Cubes]

That wear mark is normal for a R32.

The R33's engage the whole length.

[ylwgtr2]

excessive scuffing of pistons is usually due to revving them to hard before the engine is at a safe operating temperature

[DoughBoy]

Uhh that piston looks like it's been peppered alot around the crown, you sure it's "only" the oil pump to blame?

[GTRgeoff]

Looks like massive detonation leading to pickup then scoring of the bores. The oil pump looks normal for an early one.

Remember to post details in the thread in my Sig.

[druzilla32]

so thats normal for an R32?

why is the side of the piston all scratched up?

there are big scratches like this on 2 pistons, and all the other ones have similar marks but not as bad. or is normal to have scratches like that?

[DoughBoy]

At a guess the pistons from 5 & 6 have the most scuffing? It's normal to get a bit of wear on the skirts, but in severe cases where the pistons have gotten too hot (common in a detonation senario) then they are going to expand a bit more/ scuff & scrape a bit more.

If the motor has been run pretty hot that could lead to overheating, then your pistons would look like that pic i.e. detonation and scuffed hard.

[DoughBoy]

Also, got some pics of the bearings? You can tell alot about the conditions by visual inspection. What about the crank?

[DoughBoy]

Also, got some pics of the pil pump internals? Need alot more info to convincinly blame the oil pump on an engine failure.

[GTRgeoff]

so thats normal for an R32?

why is the side of the piston all scratched up?

there are big scratches like this on 2 pistons, and all the other ones have similar marks but not as bad. or is normal to have scratches like that?

<{POST_SNAPBACK}>

All the deep pitting around the top is indicative of detonation, which then starts the scoring. Then oil comes past burning in the combustion chamber causing more detonation and compression is gradually lost.

[druzilla32]

Doughboy: its from pistons 4 and 5. sorry i dont have pics of bearings and crank. but the crank was fine. i never heard and detonation or anything

geoff: thanks, i guess something like that must have happened..

i just thought it was weird how the driver didnt go all the way in and thought it may have been changed..

thanks for the info

[Mik]

Let me guess...your turbos blew as well??

That looks to me like it's had ceramic dust go through it.

[druzilla32]

Let me guess...your turbos blew as well??

That looks to me like it's had ceramic dust go through it.

<{POST_SNAPBACK}>

it looks like something like that hey, but the turbos are fine.

maby some prick took off the head and droped some rocks in there while i wasnt looking <_< <_<

[Sydneykid]

maby some prick took off the head and droped some rocks in there while i wasnt looking <_<  <_<

<{POST_SNAPBACK}>

No not rocks, Geoff is spot on, some detonation, pieces of molten piston, poor oil control, more detonation, loss of ring seal, more oil, more detonation............etc. Not the oil pump's fault, you either have a tuning problem (most likely) or an injector/fuel supply problem (worth checking).

cheers

[druzilla32]

sweet thanks for that.. i WAS going to wait before i installed the new fuel pump.. but i think to be safe i will get that put in too. the injectors were tested about 3 months ago so they should be fine.

thanks