[Vwdiesel] Poor compression Q's

[slatersfb at aol.com]

I've seen these symptoms before - at this time of year especially. 
 
My experience says there are 4 possible causes of low compression & smoke:
1- Cracked head. Not likely but possible.
2- Head gasket. Usually not associated with blue smoke. 
    Is combustion entering  the cooling system?
3- Valve lash too tight. Also not a cause of smoke.
4- Ring stuck or broken. This is most likely cause. Usual cause for stuck rings is 
    use of non diesel rated oil. Not sure what causes rings to break, but I've seen  
    a lot of them broken. Never the top ring - second or oil ring only.
 
You could try some additive but it probably won't free the rings. Most likely head needs to come off  & pistons out. Sucks for sure.
 
Bob in the Entire State
    
 
-----Original Message-----
From: Todd Osterbrink <tosterbrink at verizon.net>
To: vwdiesel at vwfans.com
Sent: Sun, 27 Nov 2005 13:41:21 -0600
Subject: [Vwdiesel] Poor compression Q's


Got low compression in 2 cylinders in a 1980 Dasher diesel.  Thinking bad rings, 
since the performance of the thing went from good to bad within a day.  Running 
bad, missing, lots of blue smoke, and starting hard.  Checked pump and cam 
timing, all in spec.  

What could cause piston rings on a 1980 Dasher diesel to go bad?  The engine has 
85,000 miles on it since rebuild (which included new over size Mahle pistons, 
rings and such).  Could it be something else?  
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