Jump to content
SAU Community

Recommended Posts

Ok so i have a rb25det neo in my 32 long story short some di*k tried to nick my rad cap and I didnt notice so car overheated bad head gasket went and compression as follows

1st cylinder 30psi

2nd cylinder 0psi

3rd cylinder 0psi

4th cylinder 60psi

5th cylinder 31psi

6th cylinder 121psi

engine was a 80000km import motor with a range of 150-147psi

so I got the head skimmed 25thou och

new gasket etc all torqued down

got a mate to do the timing (may still be out will be getting reset asap)

car wouldnt turn over

redid the comp test on the first 3 cylinders and gave up as the results where the same

there is no water in any of the cylinders so I know the head gasket is sealed

before I replaced it there was no oil in the cooling system or water in the oil

pistons dont seem to have shrink and pretty sure rings are ok

could the timing cause compression issues?

any other reasons this could be happening ?

otherwise I may just get the engine rebuilt or buy a long block (grrrrr)

Link to comment
https://www.sau.com.au/forums/topic/363610-low-compression/
Share on other sites

Timing can cause compression issue but it can't be that bad.... A cylinder might never be able to compress if one of the valves is open but if your timing is that far out, I would be surprised if you didn't bend your valves and they aren't sealing. Adjust the timing your self if you know how. Remove belt and slowly line up all markings to 0 degrees. Do a leak down test so you can source the leak. did you inspect the head when you replaced the gasket? Reading your thread over you seem to have over looked the head completely...

Edited by SargeRX8
Link to comment
https://www.sau.com.au/forums/topic/363610-low-compression/#findComment-5802198
Share on other sites

When I ripped the head off I got it skimmed and I checked all the valves etc and everything seemed ok (valves went up and down fine etc)

I didnt get it vac tested so im guessing it will be the head hoping not however :s

im taking it to my mates dad whos a mech and going to get him to set timing and do a leak down test to see whats up im guessing head will need to come off and be rebuilt or replaced

if it needs replaced id have to buy a long block as finding a neo head is near on impossible

Link to comment
https://www.sau.com.au/forums/topic/363610-low-compression/#findComment-5803694
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Hi guys . Can someone help me  I bought an Android screen for my Nissan fuga but it won't turn on   
    • My guesstimate, with no real numbers to back it up, is it won't effect it greatly at all.its not a huge change in position, and I can't see the air flow changing from in turbulence that much based on distance, and what's in front of it. Johnny and Brad may have some more numbers to share from experience though.
    • Which solenoid? Why was it changed? Again, why was this done? ...well, these wear..but ultimately, why was it changed? Did you reset the idle voltage level after fitment? I'm just a tad confused ~ the flash code doesn't allude to these items being faulty, so in my mind the only reason to change these things, would be some drive-ability issue....and if that's the case, what was the problem? Those questions aside, check if the dropping resistor is OK ...should be 11~14 ohms (TCU doesn't throw a flash code for this) ~ also, these TCU designs have full time power (to keep fault code RAM alive), and I think that'll throw a logic code (as opposed to the 10 hardware codes), if that power is missing (or the ram has gone bad in the TCU, which you can check..but that's another story here perhaps).
    • Question for people who "know stuff" I am looking at doing the new intake like the one in the picture (the pictured is designed for the OEM TB and intake plenum), this design has the filter behind the front bar, but, the filter sits where the OEM duct heads into the front bar, and the standard aperture when the OEM ducting is removed allows the filter to pulled back out of the front bar into the engine bay for servicing, a simple blanking plate is used to seal the aperture behind the filter This will require a 45° silicone hose from the TB, like the alloy pipe that is currently there, to another 45° silicone hose to get a straight run to the aperture in the front bar Question: how will it effect the tune if I move the MAF about 100-150mm forward, the red is around where my MAF is currently, and the green would be where it would end up Like this This is the hole the filter goes through  Ends up like this LOL..Cheers    
    • Despite the level up question, actually I do know what that is....it is a pressure sender wire.  So check out around the oil filter for an oil pressure sender, or maybe fuel pressure near the filter or on the engine. Possibly but less likely coolant pressure sensor because they tend to be combined temp/pressure senders if you have one. Could also be brake pressure (in a brake line somewhere pre ABS) but maybe I'm the only one that has that on a skyline.
×
×
  • Create New...