Author Topic: Lower compression on two cylinders  (Read 739 times)

0 Members and 1 Guest are viewing this topic.

Offline STi.PHa

  • Stubbly Faced
  • *
  • Posts: 24
  • Location: Edmonton
  • Ride: Subaru STi, Forester XT
Lower compression on two cylinders
« on: February 02, 2018, 12:13:29 AM »
Hello WSC members,

Compression test #
#1 - 120, #2 - 100, #3 - 120, #4 - 100

Just curious to what may cause lower compression in cylinder #2 and #4? Just seems weird that both cylinder that are affected are on the same side of the engine. The car runs find with no misfire at all. Car has forge piston and just got head rebuilt with new valves/seals and has BC 272 cams installed. Would like to look into possible causes.

Any thoughts or ideas to as why this may be? Thanks in advance.

Offline diamondedge

  • rivaling ZZ-TOP
  • ****
  • Posts: 1899
  • stir fryin' noobs
  • Location: Calgary, AB
  • Ride: 2007 WRX, 2004 FXT
Re: Lower compression on two cylinders
« Reply #1 on: February 02, 2018, 11:03:41 AM »
Did you do the test yourself? Cold or warm engine? If you started on one side and then there was a significant cool down of the engine between sides that could
explain it.

^Click^
sig by shpixx x diamondedge

Offline SlowLGT

  • beards comin in nice
  • ***
  • Posts: 745
  • Your typical Asian driver
  • Location: Edmonton
  • Ride: W164 BT, 02 C5Z06 Wasp
Re: Lower compression on two cylinders
« Reply #2 on: February 02, 2018, 12:59:52 PM »
How about a leak down test?

Offline STi.PHa

  • Stubbly Faced
  • *
  • Posts: 24
  • Location: Edmonton
  • Ride: Subaru STi, Forester XT
Re: Lower compression on two cylinders
« Reply #3 on: February 02, 2018, 08:50:16 PM »
Did you do the test yourself? Cold or warm engine? If you started on one side and then there was a significant cool down of the engine between sides that could
explain it.
Test was done by someone else. I'll do the compression test again, maybe i'll start on the side with lower compression first. Appreciate the help.

How about a leak down test?

Didnt do a leak down test yet, was looking in possible cause first. Will definitely consider it thanks