Jump to content
SAU Community

Recommended Posts

Hey guys got my compression test results on my Rb26DETT as follows.

176 180 177 155 150 170

There is a diff of 30 between cyl 2 and 5 :S Is it worth throwing on some aftermarket turbo's and power fc etc or does it look like rebuild time?

How long do you guys think the engine might last? Seems to run fine? Thanks!

Link to comment
https://www.sau.com.au/forums/topic/187549-compression-test-results/
Share on other sites

Hey guys got my compression test results on my Rb26DETT as follows.

176 180 177 155 150 170

There is a diff of 30 between cyl 2 and 5 :S Is it worth throwing on some aftermarket turbo's and power fc etc or does it look like rebuild time?

How long do you guys think the engine might last? Seems to run fine?

Should i get a leakdown test done next? Thanks!

I wouldn't break out the cheque book just yet guys. there are a couple of things that can give incorrect results. I would be happy with 150 in all 6 cylinders as long as it's even. how was the test done? hot? how much time cranking? what type/brand of gauge? how good is the battery? throttle open?

i wasn't there when the test was done but it was done by a reputable performance shop. I'm getting another compression test and leakdown done on tuesday so when i have the results ill post them up! I doubt the engine could be that bad.. the car is standard and runs very well! nice and smooth good pickup and idles perfect

I have done compression test on my rb25 and the numbers were 180psi,190psi,180psi,180psi,180psi,190psi, I was surprise with the #, then I went to check the fsm and the fsm says factory is 185 maximum and 150psi is minimum for the motor to be good and a difference (I don't remeber exactly right now) but I think was 15psi between them, so I was really surprised and I've checked to see if I had a rb25de turned to rb25det and my motor is for sure a rb25det not tuned to be a (t) so I went to check my cams and apparently they have been changed (new gasket all around the valve covers,I have to open to see what cams do I have still), so I think the best you to do is, do the compression again this time make sure if you have the battery fully charged no spark no fuel and wide open throttle, turn the ignition for about 5 to 7 seconds and make sure your tester is ok too.

This is what I have done, I'm not 100% sure about rb26 but that is what the fsm says to do for my rb25det.

I hope your motor is ok man!

gl!

Lower comp on 4 and 5 could even be a head gasket . Test again and do a leakdown to pinpoint the comp loss on 4+5.

Is it a re-built engine or stock? Dont forget carbon built up will increase compression.

Hey guys well I am happy to report apparently my engine is fine. Wen't and had another compression test done at a very reputable place and also hot and cold leakdown tests done. Compression was 150 on all 6 cyl and on the leakdown just said "nothin to worry about all less than 10%"

I dunno why it came up with dodgy readings the first time but i'm happy with that result!

Cheers

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

    • Well, I'm tired. I'm tired because about 4PM yesterday, before today's appointment someone immediately bought my bumper. They couldn't get it any other day as they're on the way back to NSW. So I had to do that big GTR conversion I had been planning. Unfortunately, the information on SAU about what you need and how this is done is incomplete. So what should be a simple bolt on affair, yeah, it's not. Did you know if you use all GTR items the bonnet won't close? This little manuever sent me into about 1am the night before trying to dodge a way to get it closed. I will have to revisit this in the next few days  - or maybe not, I may let a body shop figure it out. It all needs to come up and my motivation to pull the bumper off is low. It also seems to hit things in the bay where the GTT bonnet didn't. Yes I used 100% new OEM GTR items. Today, I had the joy of driving to the dyno looking like this: Given I had roughed in the fuel and given sensible but pretty conservative timing, I didn't really bet on having the car drive out any real difference than when it drove in. Sadly due to a miscommunication and laptop fun and games (and almost bricking the dongle, prayers and firmware updates indeed), I ended up using HP Tuner credits to licence the car that was already licenced. So in the end my laptop was used. It turns out my butt dyno is still well calibrated after all this time. The 325kw was on 74% Ethanol, the 313kw line was on 98. The other line is the 'before' line which was 281kw. While the numbers are pretty low, they're pretty in line with what you'd expect. Even if US dynos bump the whole result up about 50KW, gaining 10-15% is similar gains.  The curve of the cam is pretty much spot on with what was discussed as well. All this said, it still feels bad to not see the number you secretly want to see. Even if the car drove great beforehand, and I knew pretty confidently the car would drive out much the same way it drove in due to the nature of a wellish dialled in LS1 not gaining much if anything at all from being tuned from where it was. As expected, the car isn't particularly sensitive to running it at anywhere between 12.0 and 13.0 - And the initial timing at 20deg and 12.0 made 308KW. So 3 degrees of timing, and leaning it out to 12.7 for 5kw, anything above stopped giving any benefit until E85 (which has an additional 2 deg as before). Car itself behaved entirely fine. I found out that 100C = 1.15V! IAT at about 7pm was 19C. I might mess with the bonnet mounting.. but given the REO NEEDS TO BE CHOPPED TO FIT A GTR BAR this is possibly something I may leave gathering (more) dust until it returns to paint jail.
    • It sounds farrrrrrr too cold at your place Duncan... Here I was thinking our 10 degrees overnight is getting cold...
    • oh yeah, reminded this morning....bin lids frozen shut too
    • In my case not, because of total reno. But yeah.
    • Did you use an electronic speedo drive? Does you speedometer read all the way to 180km?
×
×
  • Create New...