Cylinder pressure test

[Beaudr33]

Hey guys! Im not sure if im posting this to the right part. Im new to this. I had my cylinders pressure tested today on my RB 25det and cylinder 3 is 140 cylinder 4 is 130 and cylinder 6 is 100. What is going to be my best option with this? Would i be better off rebuilding it or look into just dropping another engine into it? Any information or help would be greatly appreciated 

Edited March 31, 2020 by Beaudr33

[KiwiRS4T]

First of all how does it drive? Are you planning to modify it? If not it could go for another year or more. If its your daily driver look out for another engine. If not pull the engine out and strip it to see what it needs before deciding to replace it.

[Beaudr33]

1 minute ago, KiwiRS4T said:

First of all how does it drive? Are you planning to modify it? If not it could go for another year or more. If its your daily driver look out for another engine. If not pull the engine out and strip it to see what it needs before deciding to replace it.

Drives normal but every now and again it will run rough as all hell. It was my daily driver till about 6 odd weeks ago when i took it to my mechanic. Its been sitting ever since till yesterday and today when he started working on it. I do plan on doing some mods to it but now not till i work on this problem 

[GTSBoy]

18 minutes ago, Beaudr33 said:

but every now and again it will run rough as all hell

Low compression won't make it run rough. That will be something else. Dirty injectors, faulty coils, AFM, CAS, IACV, etc etc. The usual suspects on 30 year old Skylines.

If you have the money, rebuild it. You'll need ~$5k just to get a rebuild that you won't be ashamed of done though. Nothing special, mind.

[John iatrides]

It's probably build up on your valves run some seafoam cleaner through it. It happened to my rb25det valves and cylinder were caked wouldn't let the valve seat properly.

[ossy]

Out of curiosity, what are good figures for a compression test?

Edited June 15, 2020 by ossy

[GTSBoy]

46 minutes ago, ossy said:

Out of curiosity, what are good figures for a compression test?

https://www.sau.com.au/forums/topic/480462-rb25det-neo-compression-test-reference/

 

[trel]

10 hours ago, ossy said:

Out of curiosity, what are good figures for a compression test?

 An even result across all cylinders for a 25 year old motor is a good figure.