[Miata] Timing

[Larry Alster]

You don't mention year and mileage but the possibility exists that you might have a timing pulley that has slipped on the hub.  This would make the timing be way off.

As for compression test.

Remove all sparkplugs.
Unplug coilpack.  (Not needed but a good idea)
Make sure battery is fully charged
Install compression tester in cylinder 1
Hold throttle fully open and crank engine 4 or 5 cycles until the compression reading stops increasing.
Repeat for all cylinders.
Add a teaspoon of oil to any cylinder with low readings and repeat the test in that cylinder and see if it increases.  If so the rings are bad, if not the valves/guides are the problem.

I like testing the compression with an engine that has been warmed up a little so I run it and then take my time removing the plugs etc so the engine is still warm when I do the compression test.

Larry
 
White Knight      1991 Crystal White   #99 CSP
Silver Bullet        1992 Silverstone     #17 SM2  FM I+ Turbo
Honey B             1992 Sunburst Yellow
Whooosh           2004 Titanium Mazdaspeed MX-5
 
LowCountry Miata  http://www.lowcountrymiataclub.net
Masters Miata
RAGS 074
  ----- Original Message ----- 
  From: John Bodoni 
  To: Miata List 
  Sent: Monday, February 19, 2007 12:07 PM
  Subject: Re: [Miata] Timing




  On 2/19/07, Keith Tanner <keith at miata.net> wrote:


    Turn them all you want. All that matters is that they're aligned when
    you're done. Sounds like they are, so be happy with it.

  Guess that means I don't have to tear it back down to the belt again, then - thanks. 



    I'm more interested in the theory that the timing belt slipped. I'm
    not sure how that could happen.


  When I removed the valve cover, the intake side was a tooth behind the exhaust side.  When I got down to the crank, the TDC indicator was three or four (can't remember now) behind when the intake cam was aligned at the mark. 

  As for how it happened, there was a lot of slack in the belt.  I'm guessing that some idiot (i.e., your truly) didn't torque the tensioner pulley during the timing belt change two years ago.

  Now I need to figure out why it sounds like a Harley.  Guess I'll be looking for holes in the exhaust system tonight! 




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