Join Today
Results 1 to 3 of 3
  1. #1
    Senior Member
    Bored it now need to build
    it...
    Bigsi15's Avatar
    Join Date
    Aug 2015
    Location
    Bristol
    Posts
    363
    Thanks
    81
    Thanked 37 Times in 26 Posts

    Cold compression

    Guys is it normal to have the same numbers on a compression test when cold compared to when hot?? I always thought cold should be lower as the rings need heat to expand and seal correctly!

    Test was done with throttle wide open all plugs out etc. Itís a 850 t5 with a rebuilt engine and I get 150 across all cylinders

    Thanks

  2. #2
    Senior Member
    This user has no status

    Join Date
    Feb 2012
    Posts
    886
    Thanks
    135
    Thanked 356 Times in 276 Posts
    Although some state hot when doing compressions it is REALLY all relative.......when cooled off all the clearances will alter correspondingly.

    I would say cooler is better for a more accurate reading as when hot the number one cylinder always runs cooler thanks to it being nearer the water pump?

    So long as the figures are within 29psi than all is well.


    Mercedes C320CDI Sport Estate 3 litre V6 7 Gear Auto
    Remap 290bhp 628Nm torque @ 1600revs 45.1mpg

  3. The Following User Says Thank You to 960kg For This Useful Post:

    Bigsi15 (Thursday 21st June 2018)

  4. #3
    Senior Member
    Bored it now need to build
    it...
    Bigsi15's Avatar
    Join Date
    Aug 2015
    Location
    Bristol
    Posts
    363
    Thanks
    81
    Thanked 37 Times in 26 Posts
    Thanks helpful to know it’s a pretty new build so hopefully pretty tight still! Certainly starts and runs ok


 

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
ipv6 ready