Compression Test

[niran]

hey everyone

i have a Nissan skyline R32 GTS-t 1992 , it has 80 k on the body but the engine was changed by the guy i bought the car from. i did a compression test today as i was just changing the radiator hosing.

these are the scores i received

Cylinder

1-125

2-135

3-125

4-126

5-126

6-139

i wasn’t sure what the rb20det should be getting however , i was thinking some where about 160, would someone be able to let me know what i should be receiving? also how bad are my scores? if scores are bad, is it worth putting a rb25det? Instead of (if expensive) fixing the rb20det.

Thanks any help appreciated

niran

Edited April 18, 2008 by niran

[limpus]

There are 2 ways to look at it...one is that the overall figure is rather low...even for the rb20 which runs lower compression...another way to look at it is that the variation between the cylinders is not too big so its not too bad...

I'd get it checked again with another compression gauge and then go from there...comp gauges can very very inconsistant...my guess though is that it might be quite tired...

[AD4M]

yeah id say its tired if there that low, most rb20's in healthy form measure around 160

[niran]

hey man

thanks for the help, is it worth upgrading to a rb25det?

also any idea on how much it may cost to get my rb20 back to good health

thanks niran

[vitz_n1]

just buy a good rb20. they are peanuts!! and no engineering and insurance probs.

[niran]

yer i will see how it goes, i think im gonna head down to kyp and see what they also reckon and ask them if they could also do a compression check.

thanks for the help

niran

[rb26s13]

a mate of mines rb20(170,000k's) returnd 110 across all 6 on a comp test(snap on comp tester)... his motor has copped an absolute caining.. we havent been able to kill it yet its not so much about the reading as for some reason all the comp testers ive used have returned different results compared to others

you also have to remember an rb20 has very small stroke/bore dont expect it to have similar compression on the tester compared to a rb25/26 or a 30 mainly look at how even it is across the motor.. but in saying dont pay to much attention to the pressure reading.. if you havent got 3 didgets as the read out.. it might be something to look into

thats my thoughts anyway..

[niran]

True thanks for that man.

i went to kyp today they said for a half cut with a rb25det, gear box, and tail shaft and so on will come to $2000.00-$2500.00. i was thinking wether to do that or what would you guys reckon if i re built the RB20DET with aftermarket internals as it would probably come around the same price.. any way let us know what you guys think.. Wether i should ( once this engine dies) go and do the rb25det conversion or re build the rb20det?

thanks every one

niran

[Adriano]

I would just flog it till it dies, while you are waiting, build an rb30det, then you can chuck it in at your leisure

[GTR-32U]

why was the engine changed with just 80 k on the clock ? This should still be a pretty fresh engine in theory..They should still be going well with 200k on the clock

[niran]

the car itself had a built RB30 bottom with the RB26 top and it was worked so he wanted to keep that engine and just put a RB20DET back in there

[vinnie32GTS4]

hey mate when i bought my 32 GTS4 '93 i got a comp test done on it b4 i bought it..The odo read 97,000kms but who knows how tru that is.. any way i got 155 across all cylinders which the mechanic said its pretty good...i also did a leak down test and got 8% across all cylinders which he said is very good too. hope this helps

[niran]

hey vin

yer man helps alot, um im thinkin of just collecting up for a rb25det aye and just trash out this engine ahahaha..

have a good one man

niran

[R338OY]

  niran said:

hey vin

yer man helps alot, um im thinkin of just collecting up for a rb25det aye and just trash out this engine ahahaha..

have a good one man

niran

Think long and hard before you do that...

[WillGrice]

Run it til it dies, then you got nothing to worry about. haha. Just keep the fluids up. No point wasting it.

[2quik]

Jus replace it with another 20...strong underrated motor.

[bubba]

Pfft, 30 is the way to go

[niran]

Wow this is an old post i never checked it until now, dw that was when i was a bit immature. The rb20 is still going strong but I’ve been doing some research in comparison into the rb20 vs rb25 like 2 quick said the rb20 shows great results in strength specially as the rods are shorter and also the engine can rev out a big higher..

However the rb25 can spool bigger turbo’s and get bit more power out off it compared to what the rb20 can. I’m still in the process of really deciding guess I’ll keep on reading and keep asking people on this forum what they would choose and why..

Thanks guys

Niran

[Sydneykid]

  niran said:

Wow this is an old post i never checked it until now, dw that was when i was a bit immature. The rb20 is still going strong but I’ve been doing some research in comparison into the rb20 vs rb25 like 2 quick said the rb20 shows great results in strength specially as the rods are shorter and also the engine can rev out a big higher..

However the rb25 can spool bigger turbo’s and get bit more power out off it compared to what the rb20 can. I’m still in the process of really deciding guess I’ll keep on reading and keep asking people on this forum what they would choose and why..

Thanks guys

Niran

RB20 rods are longer than RB25/26.

Cheers

Gary

[niran]

  Sydneykid said:

RB20 rods are longer than RB25/26.

Cheers

Gary

ah sorry man i think i was ment to say longer rods, shorter strokes? or am i just wrong all together

Niran