Saturday, I removed the head from my BJ8 to have steel valve seats
installed because of #4 exhaust valve recession and low compression. I
figured #4 was now burned enough, I should get it fixed. After putting
on the hardtop on New Years, I could hear rougher running.
Now I see that #2, 3, and 4 pistons have 1/16 to 1/8 inch notches
missing and I can see the top ring on #4. Preliminary inspection of the
notches don't show smooth melting. So, new set of problems. I figure the
causes are:
1. Swallowed debris
2. Detonation
3. Defective pistons
Incidental facts:
A - oil never filtered only changed for about the past 40000 miles due
to faulty spin on filter adapter.
B - last rebuild in 1982 and 70000 miles ago due to melted pistons
Compression 1997 Compression 2004
Compression 2007
165 130
110
155 135
90
150 145
70
150 90
70
155 130
115
175 150
145
Any thoughts on the cause until the pistons are actually out?
Ken Freese
65 BJ8
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