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after launching my car it seems the engine has given way.

i took it to unique auto sports and they did a compression test which was pretty ugly. test came out like this, (1)26.5 (2)33 (3)35 (4)95.5 (5)95.5 (6)43.5, pretty bad hey.

they said there was a small chance that the main problem is a stuffed head gasket, but more than likely stuffed pistons and more. I really don't have the money at the moment to pay them to fix pistons, but if its just smashed valves then my mate thinks he could fix it.

from what my mate says, it sounds like the timing belt could have slipped because it is old and deteriorating, and in turn put the timing out so the valves hit the pistons and bent.

could this make the bad compression?

i don't have heaps of money to fix this car anymore so it really depends on what is wrong as to whether i can fix it. basically head gasket and head i could afford but pistons i can't, this is why i didn't get UAS to pull it apart in the hope that the problem was a head gasket and then find the bottom end was wrecked because i really can't afford that.

when you turn the key to start her up you just get starter noise and engine won't crank. but at the same time the cams are turning, so the timing belt is at least still attached.

anyone with any info would be much appreciated

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Umm yes borken timing belt would stuff most of the valves, that would be pretty bad.

Did you get a quote for the head gasket....I think you will find its quite expensive even if that is the problem (and its probably not) There is an huge amount of labour to get the head off since you have to pull the intake and exhaust/turbs off as well.

If you really don't have the money then you have 2 choices....sell in broken and get bugger all for it, or get some mates who know what they are doing and pull it out and dissassmble it yourself....then you will know what is wrong and what you have to do. But if you go option 2 expect to be off the road for a long time.

Oh or option 3 which can be cheap if the head is OK....buy and rb30 bottom end (dirt cheap), 4wd sump adapter, chuck your head on and off you go.

Sorry for the bad news, but there is no cheap rebuild for an rb26, the parts are OK but the labour is a killer

A leakdown test may tell you if the problem is c/head, bottom end or both .

Did this happen suddenly ?

Is she blowing blue smoke ?

Are the turbos still there in one piece?

If it happen suddenly you may have lost an exhaust wheel on the front turbo and she sucked some ceramic dust in. If that was the case she would be blowing plenty blue smoke .

If it happen suddenly it wouldnt be h/gasket unless you got her very hot .

As for timming belt jumping a few teeth and bending valves, maybe but when you hit valves you bend them enough not to have any compression. Take the front cover off and check the cam timming, just put the bottom crank pulley on TDC and see if the cams line up with their marks .

Like Duncan said even cil head is a big job on a GTR, its very hard to pull off on the car, you are almost better of taking the engine out to do it .

Ordinarily, bent valves would give 0 compression (I've seen an engine that had zero compression in 1 cylinder because the tappet was too tight on the top of the valve; set tappet clearance -> 180 psi compression!).

I've also seen an engine that stripped the teeth off the belt so the cam didn't turn, and none of the valves came into contact with a piston!

If the cams are turning, then the engine is cranking.

First thing is to get a leakdown test. Next would be to pull the head (it's going to have to be done anyway, even if it's a blown head gasket). If it IS valves, they can be repaired and the head replaced. If not, you can still pull the engine out for either a rebuild or a replacement.

sorry to be random, but just out of curiosity, whats the reading of the compression test when the motor is new? i did mine last month and got something like 165 for every cylinder, is that good or not?

again sorry for being off topic, and good luck with the car!

sorry to be random, but just out of curiosity, whats the reading of the compression test when the motor is new? i did mine last month and got something like 165 for every cylinder, is that good or not?

again sorry for being off topic, and good luck with the car!

165 is about right but it depends on the gauge the battery( how quick its spinning the engine)and how it was done, like WOT and engine in normal operating temp.

If all cil have the same comp thats a good indication of a healthy engine .

When the engine gets older if the top end ( valves ) is in good nick and totaly seals then compression would be higher that when it was new, because of carbon built up .

pretty sure it wasn't blowing blue smoke, or any smoke that i noticed.

the only things i noticed when it happened was that i lost power straight away, and was driving as if a cooler pipe was off but without the black smoke. so i initailly thought it could have been a turbo because of the lack of power but i'd say not. the the car died about a km up the road.

the other thing i noticed was that when i tried to accelerate, the engine made a loud ticking sound which got louder the more throttle you gave it. thats why i thought it could have been the valves.

i would love to do the rb30 thing but i really just can't afford this car anymore as it's draining all my money

i think i will get my mate to do a leakdown test, but with all that work involved just to get the head off, i think the end is nigh for the gtr. i'l probably end up selling it as is for a lot less.

Edited by KILL HSV
pretty sure it wasn't blowing blue smoke, or any smoke that i noticed.

the only things i noticed when it happened was that i lost power straight away, and was driving as if a cooler pipe was off but without the black smoke. so i initailly thought it could have been a turbo because of the lack of power but i'd say not. the the car died about a km up the road.

the other thing i noticed was that when i tried to accelerate, the engine made a loud ticking sound which got louder the more throttle you gave it. thats why i thought it could have been the valves.

i would love to do the rb30 thing but i really just can't afford this car anymore as it's draining all my money

i think i will get my mate to do a leakdown test, but with all that work involved just to get the head off, i think the end is nigh for the gtr. i'l probably end up selling it as is for a lot less.

Sorry to hear, but by what you said i wouldnt think it will be a blown h/gasket but could very well be stripped timming belt, especialy if you dont have lots of blowby .

Easy to caheck on the timing belt , just take off the top cover and put the harmonic balancer on TDC then check to see if the camgears line up with their marks.

  • 3 weeks later...

ok an update on the car, i haven't sold it yet and i was having another look in the engine bay and i found that an intercooler hose clamp was really loose.

could this have any effect on the compression?

also they did do a leak down test and it seems there is definitely head gasket damage, as cylinder 1 is leaking into no. 2

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