more blow-by pictures (1 Viewer)

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I posted similar pictures of the blow-by problem on my 83 about 6 months ago...

Here are different angles, I also cleaned off the top of the piston (#4). It is all pitted and also looks like edges broke off, melted and fused to the top. What could have caused this? Coud this have been prevented? My engine was running rough, then started smoking, on a couple of occasions, I could here the engine 'tap' really bad...Then it started smoking like crazy. Compression on the no. 4 cyl was <10 psi.

Thanks in advance,
ML
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My guess would be long term preignition (pinging)
 
Was it the only cyl that looked like that? I would expect preignition to affect all 6 cyls. Did you examine the spark plug? Maybe a piece of the plug broke off and got wedged between the the piston and the cyl? Maybe the "whaduhcallit" bolt fell out the bottom of the carb and got sucked in there. I would expect cyls 3 and 4 to be more likely to catch something than the rest since they've got the shortest intake length.
 
bull said:
Could have been a hot plug in that cylinder causing pinging for a 100K. But that is extreme. How long have you owned it? Were there metal pieces on top of the piston?


Other than carbon, oil buildup, everything looks ok. No metal pieces...Sparkplugs, valves are intack. I owned it for about a year before it crapped...

ML
 
no worries dude that is just a modification that came factory from the Neglect high performance piston products. Fix it with JB weld..

It looks as if you had the end of a spark plug break off. all joking aside
 
Also look to see if one of the cam shaft retaining bolts are missing...
 
Also could be a broken ring, but you might want to check if the bearing on the crank didn't mess up somehow and cause it to travel just enuff to hit the valves and the all the other dints and divits are pieses of the piston... could have been anything.... But here are some Ideas
 
Might be worth printing the images off and walking them into a machine shop for their inspection.
 

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