Quote:
Originally Posted by 4x4_Welder
I am talking with the guys at Delta cams about a performance cam for the 617, but need to know what the clearance is between the valves and pistons at TDC. As I do not have my engine disassembled right now, does anyone else have this spec?
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Errr as stated above at TDC the valves are shut - very shut.
The pistons on my (non-turbo) OM617 protrude from the block by about 1.6mm if I remember correctly. Check the FSM for the limits.
The valves sit in the head - just below the surface. I think they can be recessed by about 1.5mm from the surface. Again check the FSM as I'm doing these numbers from memory.
The only thing that stops the pistons from hitting the head is the head gasket. I measured my new head gasket to be 2.2mm when it is uncompressed. I forgot to measure the old head gasket - if I find it (though I may have chucked it already) I'll measure that thickness too.
If you want to see a measurement of the cam surfaces on both the inlet and outlet valves for #1 cylinder on my engine you can see that here:-
http://www.peachparts.com/shopforum/showpost.php?p=2619802&postcount=18