has anyone seen this before
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Tuned
Joined: Oct 2005
Posts: 392
Likes: 1
From: Panther Branch, NC
has anyone seen this before
bought a 7.3 w/130k out of a wrecked truck to replace my cavitated 7.3
could not here it run, it was in the back of the truck. the guy said he would
guarantee it for 30 days. put it in and cranked it. runs good but with a strange miss and hissing sound under the pass. side valve cover. removed the valve cover to find exaust coming around the second exaust valve back. removed the head and removed the valve to find 1/8 inch play in the guide and half moon in the top of the piston were the valve hit it many miles ago. the engine must have over revd and the valve tapped the piston bent the valve. and then over time it wore the guide. there was a 1/4 inch of carbon junk built up in the top of the head. got the head all fixed and everythings going back together now. I thought this might be something to share.
could not here it run, it was in the back of the truck. the guy said he would
guarantee it for 30 days. put it in and cranked it. runs good but with a strange miss and hissing sound under the pass. side valve cover. removed the valve cover to find exaust coming around the second exaust valve back. removed the head and removed the valve to find 1/8 inch play in the guide and half moon in the top of the piston were the valve hit it many miles ago. the engine must have over revd and the valve tapped the piston bent the valve. and then over time it wore the guide. there was a 1/4 inch of carbon junk built up in the top of the head. got the head all fixed and everythings going back together now. I thought this might be something to share.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
If you look at the bottom of your head and where the top of the piston is when it is at top dead center, you will realize the piston to head clearance is the thickness of the head gasket.
It don't take much to have piston to valve contact, something like passing a broken glow plug tip that got stuck under the valve when it was closing would do it.
It don't take much to have piston to valve contact, something like passing a broken glow plug tip that got stuck under the valve when it was closing would do it.
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
Visit....... http://www.members.shaw.ca/k2pilot/ there is a pic of what happens when you try to pass a tip out the exhust.....
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