Section : Engine

lack of compression 

Posted By : Robert Macdonald, 02-Dec-2003, 06:38pm

just bought my first gt6mk111 and the engine will not start, diagnostic test done for previous owner reports on the compression test as follows/ No, 1-9.50 (2) 10 (3)3 (4) 9.75 (5) 10.5 0 I intend to send it to a specialist to repair when I phoned him and told him the details of the test he says I may need a re-con engine as the piston on N0, 6 may be ruined as there is no compression it points to a probable case of overheating and would likely to weaken all the rest of the pistons .
is he correct ? anyone any ideas.
thanks robert.

• lack of compression 

  Posted By : Nigel Gibbins, 02-Dec-2003, 07:58pm

  Frist, I will assume the tappets are correctly set.
  
  The 3 bar in number three is worrying too. The six at zero definately require the head to come off for inspection. This could be burnt valves, damaged piston, warped head - this is why the head has to come off. The reason no six is indicative of overheating is that it is right at the back of the water jacket and that's where the engine will get hottest.
  
  Your 'specialist' could well be right if the engine has overheated as this can excessively wear the bearings too. Either way it will need to be inspected you can do this yourself or just bite the bullet get it reconditioned.
  
  I had an Essex V6 (in a Scimitar) that had the same problem, but the bearings were okay and all I did was replace the head - I ran for another 10,000 miles before I sold it. So the pistons aren't always scrap. It will cost about &163;150 for a new set so the choice is yours...
  
  Either way - have a look at it yourself - it's all good experience.
  
  NiG

  • f.a.o. nigel gibbons re- lack of compression 

    Posted By : Robert Macdonald, 08-Dec-2003, 10:12pm

    thanks Nigel for your reply I am sorry I did not reply sooner I have been busy between work and trying to get the car into Chick Doigs garage for repair.
    thanks again Nigel.
    regards Robert.