How Concerned Should I Be? R32 Engine Knock

[eric.marsh.bnr32]

Hello everyone,

I ran a search and couldnt really come up with any deffinitive answers. I figured I'd start a post here to see if anyone had any advice and I will be updating with remedial actions. I'll start off with the car specs and then run you through the situation.

1992 BNR32 GTR, 108,000 km on stock RB26DETT

Mods include: Power FC, HKS pod filters, Koyo radiatior, HKS intercooler with hard pipes, ORC twin plate clutch.

The other day i took my car past 6000 rpms for the first time and the cat temp light flashed rapidly. after some research i learned that the powerfc will flash the cat temp light when there is a red flag for multiple reasons. One of them being engine knock.

I changed the display on my powerfc to display engine knock and found some disturbing results. At start up, the fc will read a high of 30 knock. After start up ill clear the display and at idle it will show knock between 1-8. normal diriving up to 3500 will show 8-15. 4500 will show 20-25. at 6000 it will show 61. My power fc is set flash the cat temp light at 60 nock so that would explain why it was flashig.

From my research I've learned that the Powerfc is not the most accurate device in displaying knock, and should only be used to give a general idea. I guess all im asking is what do you all think of this? How concerned should i be? I would rather have ZERO knock lol.

This weekend I will be compression testing the engine to get a better idea of where i stand. Hopefully the results wont be to bad. As long as its not to bad (155-175 psi on all cylinders) i plan to baby the car for the next two years and save $ for a new engine.

Any thoughts or advice is welcome. Thanks guys,

-Eric

[mungy]

It's fine mate anything below 80 I believe is good, give a workshop a ring to confirm, if your in SA I'd call garage 7

[Sinista32]

I wouldn't be worried about 60 knock at 6000rpm either.

"i plan to baby the car for the next two years and save $ for a new engine". Good idea to plan for a rebuild.

Read up on the well documented oil starvation issue caused by the short nose crank, crank collar, OEM oil pump and subsequent failure of Big end bearing/s.

- Pre late 93 model R32 GTR's

This post is not meant to cause you undue concern, but rather give you information so that your aware, if not already aware.

Edit:

my compression test came back at 154 to 155 across all 6 prior to when I bought my 92 GTR in 2004 at 104,000kms.

Oil starvation and big end bearing failure within the first few months of ownership. I wasn't aware of this Achilles heel at the time.

Oil pressure gave no indication prior to failure.

Edited June 30, 2013 by Sinista32

[eric.marsh.bnr32]

Thanks for the heads up Sinista,

I have done some research on the Achilles Heel of the RB. My compression test didn't come back all that great...

1: 149 4: 149

2: 145 5: 145

3: 140 6: 140

lol planning for a rebuild!

[MagicMikeZ32]

Those numbers aren't so bad IMO. At least they are consistant. Limit the driving to something 'regular' and there is not reason it won't last another 100thou kms

[Sinista32]

Less than 10% variation so not bad as said above.

My concern with these pre93 GTR's is oil starvation.

More likely to occur during/after some spirited driving.

[eric.marsh.bnr32]

Yeah the pre 93's suffer bad from that. Wish I had a kouki! Currently saving for the necessary upgrades.

[niZmO_Man]

I've read a few people say pre 93 GT-Rs have oil starvation issues.

What I want to know is what Nissan did to the R33 engine that stops this. Long nose crank is to stop the oil pump from breaking at high engine speeds.

[Sinista32]

I believe the 2nd reason is

R32's restrictor in the head feed is too large and the return too small causing all the oil to stay up in the head too long and leaving nothing in the sump - Big end bearing Doh!

Most over fill a stocker by a half to a litre if they take it to the track.

I take it this was resolved in the 33?

Here say - I've also been given to understand the bolts attaching the oil pump can work loose causing failure.

There could be more reasons so I'm interested to hear also.

[Sinista32]

Just did a search and found this - big read, disagreements, it's got the lot - Lulz

http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/?hl=%20oil%20%20starvation%20%20cause

[MrStabby]

OP - just keep driving. With a safe tune and enough good oil that motor should last. Make sure the oil is never below the high mark, and if you track it, fill it up to the bottom of the top bump on the dipstick (IIRC about an extra litre). I have a 1990 and have tracked it plenty of times with no issue. The only fix i'm aware of in later 32s is the longer oil pump drive on the crank. There is a clear error in the design of the early cranks, but if you have a working harmonic balancer and dont limiter bash, it should last. I dont know of any design changes to fix oil starvation in the rb26's life.