[bashman40]

Hi guys my car had developed smoking issue and from the symptoms i thought my turbo seal were shot so i brought some 2860-5 my old turbos were removed yesterday to find oil in both turbos i was kind of expecting it anyway, but when removing the manifolds oil was found ONLY in and around cylinder 1?? what does this mean??

could it be-

Oil from the turbo seal?
Valve stem seals
Head gasket
Piston ring (s)

Would like to know what everyone options, in the mean while. im having a compression test done tomorrow so I will know if its the pistons or not but would like to know from others who have had the same issue?

 

[bashman40]

Forgot to mention the smoke was blue and it smelt like a 2 stoke engine, all my pipes are greasy and intercooler is greasy also.

 

[GT-R Glenn]

What is your opinion.....?

 

[bashman40]

im hoping its just the oil from the Existing turbo or maybe valve stem seals

 

[bashman40]

sorry didn’t spot the spelling mistake, its to early in the morning
typical glen picking out mistakes.

 

[bashman40]

I’ve done a compression test and this is the outcome, starting No.1 from the front of the engine.

1. 25
2. 135
3. 150
4. 145
5. 135
6. 135
(psi)

what do you guys think?

 

[godzirra]

I’ve done a compression test and this is the outcome, starting No.1 from the front of the engine.

1. 25
2. 135
3. 150
4. 145
5. 135
6. 135
(psi)

what do you guys think?

not an expert but i think it needs a rebuild...cyl 1 is clearly gone

 

[mattysupra]

o dear! You remember when you took me out in it and i said its alot slower than mine? Well thats proberly why! Your only running on 5 pistons!


the exhaust valve is where the oil is coming from i guess. I would also guess that there is something wrong with that valve stopping it shut giving the low compression reading.

Get the head of and have a look. If your lucky its just the head that needs rebuilding.


If it was a piston problem i would guess the oil would of been burnt off when last run. That oil must be coming past the valve stem seal when the car is not running.

This car has never snapped a cam belt before or something has it?

 

[bashman40]

I have never been in another R34 GTR to compare the differences so I guess it was slower then yours then it must have been running on 5 then.

Heads coming off Monday im hoping its a valve and/or valve stem seals and not pistons as you said matt it would have been burnt off when last running and loosing the oil on cylinder 1 when the car is not running? Fingers crossed.

Its never had a belt snap while iv had it.

 

[dotun]

was it only the back of the turbo's that had oil in them or did you find oil coming out the front too??

 

[bashman40]

front off turbos had oil in them also

 

[bashman40]

As my engines coming apart tomorrow its could be one of many things that has caused the problem like

Valve stem seals
Head gasket
Piston ring (s)
piston

where is the best place to source these item at a reasonable price wanted to change my cam belt while its apart with a half decent cam belt any suggestions of brand? and also where to source it from?

is there anything i have missed or should change while its apart?

 

[cleethorpes]

fingers crossed for you mate..

 

[dotun]

if your getting alot of oil in the front of the turbo's and in the intake pipes you could be getting pull over but the low comp on no. 1 it could be a few things. i had low comp no no. 6 on mine and the piston ring glands broke taking the cylinder bore with it. i hope you have better luck with yours though.

 

[bashman40]

Well head came off today and the valves and valve seals are all ok but when inspecting cylinder ones bore its seams to be damaged (scored) and it wont hold any diesel fuel which suggests piston rings? Well engines out tomorrow and block will be removed from the engine for reboring at an engine centre, can someone give me details about the reboring process from my understanding the bore gets machined (oversized) a little and you need a bigger (oversized) piston to fit it? Do all bores need to be rebored or just the one? (damaged) I will be changing all piston rings but do I need to change all pistons for oversized pistons? I will also have the head skimmed and pressure tested. Is there anything else I have missed that needs to be addressed?

 

[MorePSiTehbett4]

yes they will bolt a torque plate to your shortblock and hone ALL the cylinders, the more stock the bore usually the better(most people feel/think that stock bore builds last longer than stoker builds)

then you will just drop in a barely larger than oem forged piston that will come with a set of rings. If you are running high boost you want a looser ring gap, ask your engine builder...and make sure they specialize in the rb motors

hopefully you can just refinish the heads surface and buy a gakset set and just re attach the head without any work to the heads...you should have done a leakdown test as well, pity.

 

[bashman40]

Thanks for or reply MorePSiTehbett4. Do you know by how much they hone the bore? The original bore on a RB26's are 86mm is this correct and the same for all R32-R34 models? So I am guessing they are honed to 86.5 mm or 87mm depending on how bad the bore is? I was considering Wossner pistons what is your opinion about these, will they be ok to fit to a standard block? Is 1.5 bar of boost a lot? Will I need looser ring gaps? The mechanic that is building my engine does not specialise is RB's but is well clued up on how to remove and put this engine back together. I will be using a engine specialist to hone my block and will probably have the head pressure tested and skimmed just to be on the safe as no leak down test was done.

 

[GT-R Glenn]

yes they will bolt a torque plate to your shortblock and hone ALL the cylinders, the more stock the bore usually the better(most people feel/think that stock bore builds last longer than stoker builds)

Good grief
Ive never seen an engine have a torque plate put on it to hone bores.
Whats stock bores builds got to do with strokers ?
Stroked engines have a different stroke not necessarily a bigger bore.

then you will just drop in a barely larger than oem forged piston that will come with a set of rings

WTF
The only option is increments of .5mm

So I am guessing they are honed to 86.5 mm or 87mm depending on how bad the bore is?

NO
They will be bored to .005 under .5mm oversize and then honed to the finished bore size.
If the bores not rooted and its not a particularly worked engine see if you can buy 1 standard oem piston (assuming thats what it has)/ hone the bores and just re ring it and stick her back together.

 

[bashman40]

Thanks for the reply glen when I contacted the engine centres they wasn’t to sure why/ what a torque plate was/needed for when boring.

So I will need to ask the engine centre to increments the bore by 5mm only and fit the original piston with replaced rings?(correct me if im wrong as im not clued up with all this piston stuff still learning) from my understanding just the damaged bore will be bored (cylinder1) and the rest of the 5 cylinders will be honed. My car has original internals including pistons but when you say replace with an OEM piston isn't there going to be a gap between the bore and piston as the OEM piston will be 86mm and the bore will be alt bigger? Do you mean replace with an OEM piston which is over sized? Please point me in the right direction.

 

[Chris Wilson]

If one bore needs boring over size you must bore them all and fit 6 new over sized pistons. If you are incredibly lucky you may find any bore damage is restricted to number one, and it's so slight that a hone will clean it up. I would suggest all cylinders are lightly honed though to de glaze them. Be sure you replace pistons like with like, make and compression height wise, if you just renew one piston, and weigh it against the other 5. I'd be more concerned about WHY it has happened, det would be my odds on favourite.