Thread: compression... or lack there of.
08-07-2010, 04:19 PM #1
compression... or lack there of.
I'm looking at (maybe to buy) an 06 f-12x, 80 hrs, that has no compression on cylinder 4.
I pulled the valve cover & plugged the spark plug hole with my thumb. I didn't feel any air coming past my thumb but it sounded like I could hear air coming through a valve.
I haven't pulled the head, as I'm still not the owner.
Any thought on the most likely scenario?
08-07-2010, 07:04 PM #2
Best guess would be a valve keeper came off due to know issues with weak valve springs. 2nd guess would be smashed ring land due to detonation from poor quality of fuel.
Take a bore scope and look inside the cylinder.
08-08-2010, 04:53 AM #3
When a valve spring breaks, does it usually allow the valve to drop enough to damage the piston?
Does a oem head assembly come with vavles installed or does it need valves, springs... etc.? (the $900 one)
I don't have a bore scope, I try to stay away from situations where I might need one... lol. My only way to find out for sure is to pull the head. Just don't know if I wanna get that deep into something that could continue to snowball.
Valve spring at this point may be best case scenario, unless it has piston damage... broken land ring... eeewww, not pretty.
08-08-2010, 07:30 PM #4
The OEM head comes bare.
08-10-2010, 07:46 PM #5
- Join Date
- Aug 2010
i would pull the head and take a closer look or use a bore scope as sugested
08-12-2010, 12:35 PM #6
- Join Date
- Jul 2010
- Rock Hill, SC
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