16V Engine Compression Test Results

1. danridesbikes Newbie Joined: May 2007 Scunthorpe Posts: 27 106 GTi

   #1 16th June 2008, 22:12

   i have a 106 GTi with the 16V engine found in the VTS'
   
   just done a compression test and the results were
   
   1 - 130psi
   2 - 130psi
   3 - 150psi
   4 - 150psi
   
   anything to worry about?
2. frankie Saxperience Addict Joined: Apr 2006 Frome, down deepest, darkest zummerset Posts: 12971 VTRallye

   #2 16th June 2008, 22:16

   Quote:

   if one cylinder is 20% lower than the others and the engine has a slightly rough idle, a worn camshaft lobe could be the cause

   haynes
3. danridesbikes Newbie Joined: May 2007 Scunthorpe Posts: 27 106 GTi

   #3 16th June 2008, 22:45

   im about 14% there if my maths is right
   
   car will not idle, and has no throttle response when warm, and ive changed most parts
4. frankie Saxperience Addict Joined: Apr 2006 Frome, down deepest, darkest zummerset Posts: 12971 VTRallye

   #4 16th June 2008, 22:58

   what should the correct reading be?
   
   as it said if one was high then the combustion champers could be clogged with carbon deposits.....
5. oadamo Regular Poster Joined: Aug 2006 walsall Posts: 340 saxo vts- rwd conversion/ subaru wrx

   #5 16th June 2008, 23:08

   try a wet test. put a tea spoon of oil in each cylinder and then compare the results.
   adam

   1 user thanked this post: logic_guy
6. AlexR Saxperience Post Whore Joined: Aug 2004 Kunt & Sorrey Posts: 5763 Rep mobiles & Joes ma

   #6 17th June 2008, 11:58

   that sounds a bit low, i'd expect at least 220psi, if not 250+
   
   rogered piston rings?
7. danridesbikes Newbie Joined: May 2007 Scunthorpe Posts: 27 106 GTi

   #7 17th June 2008, 12:16

   what would be the symptoms apart from low pressure
8. danridesbikes Newbie Joined: May 2007 Scunthorpe Posts: 27 106 GTi

   #8 17th June 2008, 12:57

   technical data says bmep at new is 166psi
   
   is a bmep reading a compression test reading?
9. rich106 Newbie Joined: Mar 2007 Posts: 9

   #9 17th June 2008, 13:37

   no, bmep is not the same.
   
   mine with cams and piston cut outs was 210-215psi across the 4. a std one should be 220-225psi.
10. danridesbikes Newbie Joined: May 2007 Scunthorpe Posts: 27 106 GTi

    #10 26th June 2008, 18:12

    seems i need to do the compression test when the car is at operating temp,
    
    i did this when cold,
    
    would that explain the results?
11. user_4153 Frequent Poster Joined: Oct 2004 Cambs Posts: 630 Vts track car

    #11 26th June 2008, 18:17

    Cant see operating temperatures making much difference.
    
    Definetly sounds low to me, should be within the 220psi region as explained above.
    
    Cylinder leakage test is in need by the sounds of it.
12. danridesbikes Newbie Joined: May 2007 Scunthorpe Posts: 27 106 GTi

    #12 26th June 2008, 18:21

    its off to the garage tomorrow anyway as it wont idle when warm and ive changed just about everything