rolled a big end

[R32 GTSTT]

ive got a RB30DET in my r32 gtst. Its got a stock vl bottom end, but with a r32 gtst oil pump. After doing high speeds and reving it out to 7000rpm, my car started to make knocking noises about 10 mins later after just cruising at 110km along highway. I noticed a little drop in oil pressure. The knocking noises got worse as i slowed down and stopped. When i started it up again, it was knocked really bad.

We took the motor out and pulled it apart, to notice that one of the big ends was down to the metal, and the two shells had been rolling. Another one was down to the copper. When bearings went in the, clearances where all good.

Just wanted to know if anyone knew why they failed. Could it be that the oil pump is not pumping enough oil the the bearing at high revs and speeds, or maybe some dirt got into it?

[Guilt-Toy]

I thort the RB20DET Oil pump was a NO NO on an RB30DET combo.

How many k's did you put on the engine before you gave it this kinda treatment ? i gave mine about 5000k's before i really gave it a flogging like that and now 5000km later after many races and revs up to 7000rpm its still running fine.

Im running stock bottom end with ACL bearings but with RB25DET oil pump.

I could be wrong but I think the RB25DET oil pump flows much more.

[R32 GTSTT]

engines done 3000km. How much power are u making? so you think the bearing failed because of lack of oil?

[Guilt-Toy]

I am thinking that the car has got 330rwhp - give or take a few hp.... It was dynoed before at 310rwhp on 9psi and now its using about 13 so *shrug*

Lack of oil can do that damage to your bottom end and alot more but it could even be the tuning that caused it or even a rattle. You just never know. I would invest in a RB25DET oil pump this time just to be sure.

[Cubes]

Guilt-Toy,

Where did you hear the RB20t oil pump was a no no?

Quite a few ppls on the calaisturbo forums simply use the RB30et pump that flows less than even the rb20t pump and they haven't had any issues.

I think it really comes down to the rebuild. If it has been done properly, all it takes is to have some gunk in the block (due to the builders not cleaning properly) and you will stuff the motor.

The fact is the rb20det pump is designed for the high rev's. RB30 pump is not, so there should not be any problems with oil starvation.

That being said I think the RB25det pump is quite a bit better. Oil pressure is up quite a bit over the rb20t. On cold starts its always on the 8 or slightly higher. Once the oil is warm it sits on the first line (2) then cruise it sits just above 4 and once reving its up around 6.5-7. On the stock guage.

Was there any tell tale signs before hand? slight knock on cold starts etc?

Oil overheated caused bearing failure?

Just a few really quick questions that may help others..

What oil are you using? What oil filter?

What brand bearings? Mains & Bigends?

Was the motor Balanced?

Any modifications to the head oil restrictors in the block?

Was the oil pump pulled apart and clearances checked? (they are getting on now)

[BHDave]

I've recently completed an rb20-25 swap in my r32 and with an aftermarket gauge found that the RB25 runs an additional 10psi at 3000rpm, around 60psi total. 3000rpm is 5th gear 110kms.

[Cubes]

Whats that relate to on the stock guage? (even though the stock guage isn't the most accurate)

[Cubes]

Just so ppls know in comparison to their motor..

I've got forgy's that run a fairly large 0.004" I think it is clearance.

On cold morning starts they knock a little for the first couple of seconds then have a really light knock until the oil pressure drops (oil is warm) and pistons have expanded. Once warm it is silent.

The knock/slap can only be heard when standing right next to the car.

I tend to like the knock/slap actually. At first I thought it was the head and had it checked out.

I don't use a drop of oil (which is suprising considering the bore clearance).

It used quite a bit in the first 1000km's but then all of a sudden cleared up and now literally doesn't use anything.

I'm curious as to how some others have had experience with their motors.

In the 6000km's I've traveled I've done 4 oil changes.

[GTRgeoff]

R32 GTSTT, sorry to hear of your engine failure. while at this time I don't have any extra points to add over the other good advice given, I, and I'm sure many others, would appreciate and benefit if you posted details of your engine failure in the thread in my sig.

[BHDave]

Whats that relate to on the stock guage? (even though the stock guage isn't the most accurate)

depends what mood the stock guage is in.

if it is working properly it is generally a bit above the 4bar line

[proengines]

A common cause of conrod bearing failure that hasn't been mentioned is detonation. Have a look at the top half of the other conrod bearings and see if they are marked from say 10:30 to 2:30 (if the big end bore of the conrod was a clock with the piston sitting straight up, looking at the front).

Marks here are a fair sign that the engine has been detonating and it would be worth playing with the tune when you get it going again, taking out a little timing or putting in a little more fuel.

Just a thought anyway.

[R32 GTSTT]

ok, so you think I should maybe put a gtr, or 25t oil pump just 2 be safe, and just put brand new orignal vl turbo bearings??

[R31Nismoid]

i've got an N1 pump on my 25... better to be safe IMO.