Lowest Compression On Rb25?

[hairdryer33]

As above, whats the lowest psi people have seen? Ive got 120 4+/- across all 6, it feels slow!

[boostn0199]

If it actually is at that compression then yes it is getting low but if you want to know the extent as to what is wrong a leak down test will show you more specfically.

[hairdryer33]

Ok, im thinking it I put new rings in it, that may help everything else is fine no weird knocks etc

[89CAL]

How do you know its not your valves or anything else

Edited November 14, 2014 by 89CAL

[hairdryer33]

Good point, I dont. What needs doing if its a valve issue

[jiffo]

If it's a stock cam Rb25det, 120 is way low, must be very poor when driving off boost.

I'd think hard about doing it up as opposed to buying a 2nd hand engine, something coming with a compression test at least.

Unless you're dead set on building up an engine, you'll quickly find parts and labour costs will exceed the cost of a replacement.

[Dose Pipe Sutututu]

Just add more boost, drive it till she pops.

[Piggaz]

Have you tried another gauge? Maybe that one just reads low?

I agree with Johnny. If it's still running well just keep flogging it. A stock replacement engine is cheap enough.

[Ben C34]

Could be cam timing out.

[Dose Pipe Sutututu]

Have you tried another gauge? Maybe that one just reads low?

I agree with Johnny. If it's still running well just keep flogging it. A stock replacement engine is cheap enough.

Damn straight, that's what I'm doing with my 400 000km motor, seems to like getting thrash at the track too.

23 psi seems like a good number lol

[hairdryer33]

Two different gauges, im thinking a 2nd hand engine soon. Timing is not out. Its sluggish down low but puuls ok 80kmh onwards.

[jjman]

Two different gauges, im thinking a 2nd hand engine soon. Timing is not out. Its sluggish down low but puuls ok 80kmh onwards.

is this based on experience with other RB25's with similar setup or just your feel on this as the first RB25 you have driven?

Nonetheless, 120 is pretty low. Needs more boost to compensate

Incidentally how many k's on the clock?

[hairdryer33]

No been in others. Haha nah she'll blow captain! Its a daily so have to treat it nicely. 220k roughly

[MBS206]

How do you know the Cam timing (Not the ignition timing) isn't out?

If it's at 220K, it could be that the timing is out a tooth if it has had a timing belt done recently.

[hairdryer33]

Timing belt was done at 210,000 by rotech. Anyone in nw tas would know its the place to go.

[hairdryer33]

Anyone else running a tired engine?

[Ben C34]

I would still check cam timing. People make mistakes.

I recall Stao from Hypergear having his cam timing out after a mechanic installed cams to his car.

Doesn't take much to check.

[KiwiRS4T]

ideally you would do a leakdown test. Alternatively you can just squirt a little oil in the cylinders and see if the compression comes up - that indicates that its rings rather than valves.

And do pull the cover off and check the cam timing.

Yes heaps of people are driving tired engines. The main thing is that the compression readings are close together as yours are. Are you using heaps of oil? Your car could go for years (or not).

[hairdryer33]

Ok ben, will do today, from memory its all within 5-7psi of each other

[Dose Pipe Sutututu]

New turbo and more boost will do it, make up for the low compression