The gasket thickness is to allow for piston protrusion above the top of the block. Machining the head has no effect on piston height.
And according to RAVE the head should not be machined, although I believe that some have done it.
The gasket thickness is to allow for piston protrusion above the top of the block. Machining the head has no effect on piston height.
And according to RAVE the head should not be machined, although I believe that some have done it.
Dave.
I was asked " Is it ignorance or apathy?" I replied "I don't know and I don't care."
1983 RR gone (wish I kept it)
1996 TDI ES.
2003 TD5 HSE
1987 Isuzu County
RE Gasket thickness, correct...
TD5 head gasket thickness
However, plenty have had the head skimmed with no ill effects![]()
Dave.
I was asked " Is it ignorance or apathy?" I replied "I don't know and I don't care."
1983 RR gone (wish I kept it)
1996 TDI ES.
2003 TD5 HSE
1987 Isuzu County
It's also to compensate for the valve to crown clearance Dave, not just crown protrusion.
Usually a skim wont cause an issue if its never been machined before but it depends which side of "erring" it ended up with when the original gasket thickness was selected.
My research tells me that no more than .009 thou is the max that can be taken off a Td5 head. With this amount the valves should be ok.
Dave.
I was asked " Is it ignorance or apathy?" I replied "I don't know and I don't care."
1983 RR gone (wish I kept it)
1996 TDI ES.
2003 TD5 HSE
1987 Isuzu County
My 20 years in engine building tells me it's a mistake that is still made.
The .009" you take off the head moves the valve face .009" closer to the piston crown unless you recut the valve seats to adjust the valve face protrusion from the head face back to its original measurement.
The overall clearance you're measuring is the crown to valve face and this is where the head gasket thickness comes in.
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