Jump to content
SAU Community

Recommended Posts

Hi all,

I'm thinking about buying an RB26. The compression has been tested by a reputable shop and came out an average of 125 psi, with a deviation of 2 psi either way.

Looking in the Nissan RB26 manual, it says that new it should be 171 psi and the lower limit should be 128 psi with a deviation of 14 psi.

The shop who tested it seemed to think that as the values were consistant and the engine runs well and makes good power (400 rwhp - not stock turbos) that it either has forged pistons or a thicker head gasket.

Opinions? Ideas?

Cheers,

Cam

Link to comment
https://www.sau.com.au/forums/topic/71051-rb26-compression-test/
Share on other sites

tough call big guy ,

short of actually removing the head ( my personal prefference ) ,

you could look for signs of a rebuild , new gaskets , belts , pumps etc?....the sump seal is an easy 1 to spot , it's all gasket goo..grey is origonal & orange is replacement ( not always , but both are nissan goo just the grey one is much more $Bling$ )

Good luck

Hi all,

I'm thinking about buying an RB26. The compression has been tested by a reputable shop and came out an average of 125 psi, with a deviation of 2 psi either way.

Looking in the Nissan RB26 manual, it says that new it should be 171 psi and the lower limit should be 128 psi with a deviation of 14 psi.

The shop who tested it seemed to think that as the values were consistant and the engine runs well and makes good power (400 rwhp - not stock turbos) that it either has forged pistons or a thicker head gasket.

Opinions? Ideas?

Cheers,

Cam

Get them to do a leak down test, that will give a much better indication of engine condition, a compression test has too many variables.:P

Rep - I'll have a closer look at those things next time I check it out..

SK - Agreed. I'm guessing a leak down will tell me if there is a problem - no leaking therefore the compression is ok.

Cheers,

Cam

Not necessarily guys

I also have a R32 GTR (doesn't everyone) - when I did a compression test it was a steady ~150psi across the block (+/- 5psi) - but a leak down test told a VERY different story (pots 4 and 6 were shot). Pot 6 always goes first – and points to low fuel pressure apparently (some fault with the plenum design??)

I saw the pistons and the bore once it was striped down – and they were in very bad shape (now running 1 size over)

BUT

She also ran fine (even @ idle) and running 15psi she pushed out 210awkw with R32 N1 turbos. Not bad with only 4 pistons – and everything else standard.

Only reason I found out was that I wanted to do some more mods – and get a LITTLE more power – so I started with a full check over of the engine. Ended up pulling the head off just to make sure – and things went down hill from there.

A FULL rebuild fixed the problem ($10K latter)

Now pulling 280+awkw ;)

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

    • Price seems pretty good to me. Also seems a hell of a lot cheaper then buying another vehicle that only ever gets used for towing.  I'm a long way from you mate, I'm a couple of hours out of Brizzy. 
    • New [400]Z, they're available in manual and you don't have to worry about parts scarcity. 
    • Just planning to have the wiring neat and hide as much as possible.
    • The sodium acetate, mixed with citric acid, doesn't actually buffer each other. Interestingly though, if you used Sodium Acetate, and acetic acid, THAT becomes a buffer solution. Additionally, a weak acid that can attack a metal, is still a weak acid that can attack a metal. If you don't neutralise it, and wash it off, it's going to be able to keep attacking. It works the same way when battery acid dries, get that stuff somewhere, and then it gets wet, and off it goes again breaking things down. There's a reason why people prefer a weak acid, and it's because they want TIME to be able to be on their side. IE, DIY guys are happy to leave some mild steel in vinegar for 24 hours to get mill scale off. However, if you want to do it chemically in industry, you grab the muriatic acid. If you want to do it quicker at home, go for the acetic acid if you don't want muriatic around. At the end of the day, look at the above thumbnail, as it proves what I said in the earlier post, you can clean that fuel tank up all you want with the solution, but the rust that has now been removed was once the metal of the fuel tank. So how thin in spots is your fuel tank getting? If the magazine on the left, is the actual same magazine as on the right, you'll notice it even introduces more holes... Well, rust removal in general actually does that. The fuel tank isn't very thick. So, I'll state again, look to replace the tank, replace the fuel hanger, and pump, work out how the rust and shit is making it past the fuel filter, and getting into the injectors. That is the real problem. If the fuel filter were doing its job, the injectors wouldn't be blocked.
    • Despite having minimal clothing because of the hot weather right now, I did have rubber gloves and safety glasses on just in-case for most of the time. Yes, I was scrubbing with my gloves on before, but brushing with a brush removes the remaining rust. To neutralize, I was thinking distilled water and baking soda, or do you think that would be overkill?
×
×
  • Create New...