Back

 Rb25 Low Compression - 80 in cylinder 4  

Post Topic
log in
  • log in
  • Standard User
  • Member No.: 77,931
  • Joined: 22-August 07
  • Posts: 160
  • From: boronia heights
Post #1 post 30th July 2009 - 11:10 PM
ok so i have only 80 compression in cylinder 4 of my rb25det, all of the other cylinders vary between 145 and 150. am wondering if there is any way i can find out if its the bottom end or top end without taking off the head. car still runs the same and boosts fine but is filling up the catch can, but only under boost. there's no knocking noise from bottom end but when i take off the oil cap in can hear a slight ticking noise

would one of them little probe cameras be able to shed any light on my problem?

any ideas on most likely scenario, other than the fact it probably needs a rebuild.
TOP
pipster11
Post #2

you could take the rocker covers off and get someone to turn it over while you look at the cams going round

just did this on my 31 to check everything was ok, and it was lol

thats pretty much all you can do

should take you an hour at most to check

ke_rolla
Post #3

by the sounds of that u have done a ring land on piston 4, either the oil ring has colapsed or blown out which is causing ur catch can to fill up and the sudden loss of compression...

SSS300HP
Post #4

yeah i would be guessing rings as well to drop that quick!!! Also just check around the head to see if it hasnt blown??? But it does sound like rings

pipster11
Post #5

just remebered how to check what ke_rolla just said

chuck a little bit of oil down the spark plug hole and then crank it

if you get good comp its the rings or piston

if its the same its a valve

log in
Post #6

thanks for the help guys will do said advice on weekend

  • Member Login

    If you have a BoostCruising account enter your user name and password into the yellow box.

    Alternatively, you can quickly login with Facebook.

    If you don't have an account create one below.

    Create Account
  • Forgotten your password?
  • Login with Facebook

    Login using your Facebook account!

1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
Loading...
x