Compression Results

[Mattw_83]

Just had compression test done

Results came back rubbish

Between 111-114 across all six.

Mechanic said he is going to use another dial just to be certain, as the wear is very even.

f**king disappointing,

Question :

Wouldnt rubbish figures like that be showing serious deteriorating performance signs??? I had this done out of curiosity as i was just about to upgrade turbo. Still performs like it always has. Really well. Has a 125k on the clock

[R31Nismoid]

1. They are consistent - this is good, not rubbish

2. It could have been done slightly wrong - meaning there is no actual issue

Given consistent results across all 6 it's either one of two things.

The motor is a little bit tired or the test was perhaps not dont quite correctly.

Have it retested perhaps by another workshop just to see what happens. With legit km's you'd probably expect closer to 130-140 but personally i wouldnt get too excited just yet until it gets retested.

If it comes back and does show that it is similarly low then ye the motor is a bit tired and perhaps not a good idea to ask too much of it. 250rwkw on a safe tune would be about sensible limit IMO.

[Mattw_83]

  On 15/04/2011 at 2:45 AM, R31Nismoid said:

1. They are consistent - this is good, not rubbish

2. It could have been done slightly wrong - meaning there is no actual issue

Given consistent results across all 6 it's either one of two things.

The motor is a little bit tired or the test was perhaps not dont quite correctly.

Have it retested perhaps by another workshop just to see what happens. With legit km's you'd probably expect closer to 130-140 but personally i wouldnt get too excited just yet until it gets retested.

If it comes back and does show that it is similarly low then ye the motor is a bit tired and perhaps not a good idea to ask too much of it. 250rwkw on a safe tune would be about sensible limit IMO.

Good to hear i guess.

Was only aiming for 250rwkw give or take and decent response.

Its being retested with another dial. If its still the same, taking it elsewhere for one last crack regardless.

Cheers for your response.

[SiR_RB]

Was it done with thenengime hot? Hot or cold compression test will vary alot too

[Mattw_83]

Well i drove from ryde to the city. Dropped it off at around 9:30 and got the results around 12:30. So i guess unlikely to be cold.

[ylwgtr2]

drop a touch of oil down the plug hole then see what you get

[tridentt150v]

Is it using oil?

[Mattw_83]

I get it changed every 5 thousand. Its not burning oil or blowing excessive smoke. Doesnt go through coolant either

Does however not seem to peak as much boost. Originally tuned for around 13psi. Now under load (and even on the cooler nights recently) only seems to reach just on 11psi.

Occasionally the idle drops off slightly from around 700 to 500 revs and has stalled once or twice coming to a real quick stop at the lights.

Ive never had the 02 replaced.

Edited April 15, 2011 by Mattw_83

[simpletool]

Those last few issues seem like a BOV leak

[Mattw_83]

1 - 110 PSI

2 - 111 PSI

3 - 114 PSI

4 - 113 PSI

5 - 112 PSI

6 - 111 PSI

Two tests on two separate guages...

[Trozzle]

Ever had the head gasket replaced?

[Mattw_83]

Nope. Never.

[quick31]

The engine sounds like its a little tired. Is the motor breathing @ all, check your intercooler piping for oil if you still run a standard breather setup.

[DVS JEZ]

was the 2nd test done hot? and was the throttle fully open when testing?

[Mattw_83]

second test not hot. Id have to ask about throttle body i dont know. There looking into it more on monday.

Im just not convinced!

Maybe its denial...

[32rrr]

I wouldnt worry about it it to much considering the numbers are very very even, as someone else said, put a couple drops of oil in through the plug hole and do the test again and also do a leak down test and it'll tell the story a bit better, i'd say its just old age and or probaly had a headgasket changed to a thicker item before you bought the car

Slap your new turbo on and screw the boost into is what i'd be doing.

Big thing i find with comp test results is from gauge to gauge it varys but as long as the numbers are with in 5% of each other she's still good!

Edited April 15, 2011 by 32rrr

[Mattw_83]

  On 15/04/2011 at 7:08 AM, quick31 said:

The engine sounds like its a little tired. Is the motor breathing @ all, check your intercooler piping for oil if you still run a standard breather setup.

Apologies for the ignorance mate, what do you mean by breathing?

[tridentt150v]

Start car, better with a mate, so he can blip the throttle.

Take your oil filler cap off and see if it is breathing heaps = indicates blowby = rings/liners worn. Keep a rag handy,so you can half cover the hole just in case it starts to spit oil.

Do it with a couple of cars if you can so you can see the difference.

[Trozzle]

  On 15/04/2011 at 8:12 AM, tridentt150v said:

Start car, better with a mate, so he can blip the throttle.

Take your oil filler cap off and see if it is breathing heaps = indicates blowby = rings/liners worn. Keep a rag handy,so you can half cover the hole just in case it starts to spit oil.

Do it with a couple of cars if you can so you can see the difference.

you can blip the throttle by pulling the cable with your hand lol....last time I took the filler cap off and did it, the cams flicked oil all over my face bahahaha

[mii11x]

  On 15/04/2011 at 2:23 AM, Mattw_83 said:

Just had compression test done

Results came back rubbish

Between 111-114 across all six.

Mechanic said he is going to use another dial just to be certain, as the wear is very even.

f**king disappointing,

Question :

Wouldnt rubbish figures like that be showing serious deteriorating performance signs??? I had this done out of curiosity as i was just about to upgrade turbo. Still performs like it always has. Really well. Has a 125k on the clock

hey mate,

for your interest i just did an engine swap but tested my rb20 (cold test) which has 339000km on it, i got between 120-127 on mine

mick