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Registered
Join Date: Dec 2003
Posts: 119
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fly cut heads and base gaskets
Broken head studs caused scoring in the head mating surface so I had the heads cut .25mm at the same time I had a valve job. Wayne's book says I should double up on the base gasket, but I was thinking that the valves would be seating that much further in their seats and therefore basically equal the amount cut from the heads. I will still measure the valve/piston clearance but as a starting point I plan to use only 1 gasket?
Does this make sense? Comments? Jamie
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78SC Porsche Targa, 71 911T 86 Mazda RX-7 ITS SCCA racer 05 Porsche Cayenne 05 F350 Powerstroke 90 Miata |
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05-18-2004, 01:44 PM
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Registered
Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,472
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it will probably be ok. whoever cuts the heads needs to measure them between the cam tower mating surface on the spring side, and the cylinder surface, to be sure they haven't been cut already, and if so, how much. they measure 84.50- 84.55mm stock. yours should measure 84.25-84.30 with .25 removed. much more, and the thrust plate will be offset in it's hole in the chain housing too much, unless you shim the cylinders out.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 Last edited by john walker's workshop; 05-18-2004 at 01:54 PM.. |
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05-18-2004, 01:50 PM
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Join Date: Jul 2000
Location: So. Calif.
Posts: 19,910
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"...and the thrust plate will be offset in it's hole in the chain housing too much, unless you shim the cylinders out...."
....and/or you can machine the chain boxes an equivalent amount to re-center the hole around the cam. If the valve-to-piston clearance is okay, you can also leave it like that w/o shimming the cylinder base as the compression ratio drops slightly with added base gaskets. Sherwood |
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05-18-2004, 10:58 PM
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