Jump to content
SAU Community

Rb25Det Compression Results

juicy3

By juicy3,
in Engines & Forced Induction

 Share

Recommended Posts

juicy3 Apprentice

juicy3

Posted
Posted

Hey Guys,

Did a compression test today on my r33 and was Pretty happy until the 6th piston (closest to driver)

Here were the results

1 - 150

2 - 152

3 - 156

4 - 155

5 - 150

and then :((

6 - 90

put about 5 - 10ml of oil in there and it only went up to about 93 :((

Not too happy with that

Could anyone shed some like on what might be wrong and ways to go about fixing it??
I do have a video of the tests if they are relevant to anyone?

Thanks Guys
Josh

Link to comment
https://www.sau.com.au/forums/topic/426387-rb25det-compression-results/
Share on other sites
SargeRX8 Grand Master

SargeRX8

Posted
Posted

Maybe you could be hopeful, somewhat, and hope for a slightly damaged head gasket in cylinder 6. Before pulling it apart you could do a leak down test. That will tell you if its the head or your piston and if it is the head, is it the intake or exhaust valve.

SargeRX8 Grand Master

SargeRX8

Posted
Posted

How does a leakdown test tell you the difference between any of those? Best I can tell all it tells you is that X amount of air is getting out.

If you hear air gushing out of the exhaust you know you have an exhaust valve issue, if you hear air gushing out of the pod filter you have an intake valve leak, if you hear air gushing out through your dip stick or it pops out, then the seals or piston are at fault as air is getting past them and pushing the dipstick out. If the air is leaking from a leak down test where is it going? Where ever the problem is, that is where the air will be coming out from. Its pretty simple.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • iain_ST44GA
      M35 VQ25DET starter motor

      By iain_ST44GA · Posted

      Hi Guys, Does anyone know any aftermarket part numbers for a starter motor to suit the VQ25DET? I can find lots of alternative part number for the VQ35DE, which I assume would fit, but there is a lot of conflicting information out there. Thanks..
    • Murray_Calavera
      R33 GTR running -9 with no tune

      By Murray_Calavera · Posted

      I don't understand how this hasn't boiled down to - Upgrade the turbo when you have everything required. ECU, injectors, fuel pump, turbo, etc. Do it all at once.  If you don't have everything required, just enjoy the car as it is and keep saving up your pennies. 
    • Duncan
      R33 GTR running -9 with no tune

      By Duncan · Posted

      Sounds like you've got an interesting adventure ahead here with local support if you have trouble! My guess is that, unboosted, you will be OK with a small upgrade like -9. What will happen is that once the stock ECU sees more airflow than it expects it will add a heap of fuel and pull a heap of timing to be safe because it can't understand how it could get that much air without there being an issue. You will see clouds of black smoke and it won't pull hard through the midrange and top end. So, overall it will be a bit frustrating but should be OK. If you are still nervous set the base timing back 2o through the CAS, but it will be even more sluggish everywhere. As said above through...this is not my guarantee your engine won't be blown into a million pieces, leaving you looking for very hard to find parts A better idea is get a computer with logging ASAP, wire in a wide band O2 sensor and a use remote tuner. I've done multiple cars this way and while it is not as good as a specific tune on a dyno they can get it 90% right. I'd suggest if you can afford an R33 GTR these days you can afford an ECU and tune. And if you can't afford that you sure won't be able to afford the rebuild if it goes bad in the meantime,.  
    • Duncan
      New kid on the block

      By Duncan · Posted

      Yeah it would be nice if someone took the time to put that sort of information together, but there are a lot of variations in looms. I think you are making this way hard for yourself if you just want to get it running....sourcing an SR20 with the right wiring will be a billion times easier than matching the RB loom to an S15 chassis. If you do end up going this way, you just need to trace every wire in the loom with a multimeter, 95% of them will go to a location you can confirm at the ECU.....and then post it up for the next person who needs it  
    • Duncan
      Coolant leak?

      By Duncan · Posted

      Just top it up with water, and keep a general idea of how much you added. It is normal for water to be pushed into and pulled out of the reservoir through the cap, and it should not be more than half full or it will be likely to overflow when hot. Any decent mechanic can do a pressure test of the cooling system to confirm if you have a leak. Keep in mind if it is only leaking a little and when hot it may well evaporate before you see it hit the ground
×
×
  • Create New...