<VV> engine noise mystery

djtcz at comcast.net djtcz at comcast.net
Fri Apr 18 11:13:56 EDT 2014

A certain amount of scratching on piston skirts can be "normal" if cleaning efforts before and during assembly were less than perfect. 
I think Smokey Yunick or Bill Jenkins said OHV V8 owner's can expect slight scratching from migrating valve spring and retainer debris. 

I would try gently but insistently inserting feeler gages in the 0.0015" to 0.010" range between each skirt and cylinder. Quality feeler gages are somewhat deburred on the edges, but I would probably buff or scotchbrite and then clean the rounded tip before probing. 
If much more than a 3 or 4 can be inserted deeply I'd suspect an clearance issue. 

Dan T 

Date: Thu, 17 Apr 2014 10:07:26 -0800 
From: "Bob Gilbert 1" <bgilbert at gilberts-bc.ca> 
Subject: Re: <VV> my last engine noise mystery 
The more digging I do the more I'm beginning to think that it might be 
piston slap and the metallic noise that I hear is the piston hitting the 
cylinder wall. 
When I used a really bright flashlight I did seem some scuffing on the 
piston skirts. It's mostly minor scuffing but there one is a scratch big 
enough that I can just feel it with my finger nail. 
My borescope should be here in a few days and that hopefully will rule out 
any damage on the top side of the cylinders. 
If there is no damage, then I'm back to the possibility of piston slap and 
if so, I'm not sure what I will do. Opinions vary all over the map from 
ignoring it to doing a rebuild. 


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