Low Compressions?

[Slattery Gts-t]

Just did compressions on my r33 and got these rather low figures

1 - 105

2 - 108

3 - 105

4 - 97

5 - 110

6 - 106

Tried cylinder 1 again with some oil and got near 200psi, does this indicate my rings are worn to the $hit house ? it uses a bit of oil here and there aswell

Edited October 18, 2011 by Slattery Gts-t

[mico]

lol time for a refresh mate !

[The Mafia]

I'd try a different gauge (decent one) and a leak down test.

But, those figures are shit, engine is about to blow son.

[Slattery Gts-t]

Yeah its the lowest iv ever seen across the board in the few iv tested

How much is involved in changing the engine in an r33? taking into account i have acess to a hoist, full toolkit and a few extra hands

[Slattery Gts-t]

I think the gauge is pretty accurate because our compressor reg is set to 100psi and when i sealed the air gun to the gauge and shot 100psi threw it the gauge went straight to 100psi

Im pretty confident my engine is shagged lucky it still runs alright, my odo shows 117,000 im taking it that this is wrong or is it not unusual for this to happen to these engines at these kms?

[Ke55pig]

missus 33 has got couple at 50 and rest like 80 still dailyed and going not strong lol slower the a na lol

[Slattery Gts-t]

Haha oh well that gives me hope that it will last until i organise another engine, Only had this car a few weeks and from the start iv always thought it was lacking power especially off boost well this explains it

[Guilt-Toy]

just drive it.

[DVS JEZ]

Moar boost to compensate

[The Mafia]

My engine had 140,000kms on it and 50,000 of that was at 300rwkw.

Compression test came up at 160psi across all 6. It only had a 2psi variance.

Seems that car has had the shit flogged out of it. Surprised it hasn't blown number 6 yet.

[Ke55pig]

U got plenty of time been like that couple months

[Slattery Gts-t]

Just thought id update

I was nearing the end of a 300km trip on saturday when all of a sudden there was a loud 'clunk' followed by lots of quieter "clunks"

First i though it must be bottom end related as this was unhealthy to start with but turns out my timing belt jumped a tooth on the intake cam and mashed a few valves

It only jumped one tooth though is this usually enough to smash valves ? now compression figures are around the 50psi mark with cylinder 4 showing absolutely nothing

[Moodles2]

Usually it takes 2-3 teeth, 1 tooth usually just makes the engine sluggish and lazy

[The Mafia]

This is why you refresh a buggered engine - only costs a lot more when you have to start repairing damage. Especially bent valves.

[Slattery Gts-t]

Im replacing the whole engine it just didnt get here in time before this one shit itself

But your right because i plan to rebuild this engine and now i may have damaged the head

Lance: thats what i thought too so its got me buggered, im certain it was spot on before it happened

[JonnoHR31]

This is why you refresh a buggered engine - only costs a lot more when you have to start repairing damage. Especially bent valves.

yer damn that low compression putting all that extra strain on the timing belt.....

1 tooth isnt anywhere near enough to mash valves, are you sure its only 1 tooth?

[paulr33]

fyi rb25 with 244,000 and still going well

no idea on compression though

[Bsa]

iv got a rb25 all but ready to asemble if you want it has port and polished head, rb26 rods treated and balanced, crank is balanced all it needs is pistons and block macheined to suite pm me if intrested.

[SargeRX8]

I'm surprised to see a 100psi jump with the added oil. These engines can't compress to that level.

[AngryRB]

what about if the car has some aftermarket cams? wouldnt that make the compression drop , my first car had the cam reground and the compression fell from 150psi to 110psi,

that would explain it having fairly low km's and down on compression...