Been asked to death but...
- Thread starter shaggy
- Start date
After doing some more research:
Bore: 3.84"
Stroke: 3.40"
Head Gasket Thickness: .018", with an assumed bore of 3.90"
Head cc: 48
Piston Dish cc: 25
Deck Clearance: .02"
Static compression of: 9.05
Static compression of: 9.25 (with 46cc head)
Static compression of: 9.46 (with 44cc head)
Also, my research indicates that the factory deck clearances run about .050-.070". Would it be a problem removing .030-.050" from the deck? This is a NA application, btw. Anyone know what the bore of the 25524599 steel gaskets are? It doesn't make much difference for the compression ratio calculation, but I'd still like to know. The pistons used for this calculation were Sealed Power Hypereutectics. It looks like it'd be tough (expensive) to get 9.5/1 compression. I guess the heads could be milled too. Anyone know approximately how much chamber volume is removed for every .010"? Lots of questions ...
Bore: 3.84"
Stroke: 3.40"
Head Gasket Thickness: .018", with an assumed bore of 3.90"
Head cc: 48
Piston Dish cc: 25
Deck Clearance: .02"
Static compression of: 9.05
Static compression of: 9.25 (with 46cc head)
Static compression of: 9.46 (with 44cc head)
Also, my research indicates that the factory deck clearances run about .050-.070". Would it be a problem removing .030-.050" from the deck? This is a NA application, btw. Anyone know what the bore of the 25524599 steel gaskets are? It doesn't make much difference for the compression ratio calculation, but I'd still like to know. The pistons used for this calculation were Sealed Power Hypereutectics. It looks like it'd be tough (expensive) to get 9.5/1 compression. I guess the heads could be milled too. Anyone know approximately how much chamber volume is removed for every .010"? Lots of questions ...
Now lets make things more interesting. Using a 3.0L piston we get the following:
Bore: 3.84"
Stroke: 3.40"
Head Gasket Thickness: .043", with an assumed bore of 3.90"
Head cc: 46
Piston Dish cc: 12
Deck Clearance: .06"
Static compression of: 9.29
Static compression of: 9.85 (with .018” head gasket)
Static compression of: 8.95 (with .060” head gasket)
With this option I don’t need to deck the block or mill the heads. Has anyone here actually used the 3.0L pistons? The 82-85 pistons are listed as flat tops, and the 85-88’s are listed as 12cc dish. The compression distance and pin diameter look to be the same as the 3.8L. Am I missing something that would keep me from being able to use these? A side benefit is the ability to swing the compression ratio by almost a full point with a head gasket change. Comments anyone?
Bore: 3.84"
Stroke: 3.40"
Head Gasket Thickness: .043", with an assumed bore of 3.90"
Head cc: 46
Piston Dish cc: 12
Deck Clearance: .06"
Static compression of: 9.29
Static compression of: 9.85 (with .018” head gasket)
Static compression of: 8.95 (with .060” head gasket)
With this option I don’t need to deck the block or mill the heads. Has anyone here actually used the 3.0L pistons? The 82-85 pistons are listed as flat tops, and the 85-88’s are listed as 12cc dish. The compression distance and pin diameter look to be the same as the 3.8L. Am I missing something that would keep me from being able to use these? A side benefit is the ability to swing the compression ratio by almost a full point with a head gasket change. Comments anyone?
Yep. About .085" in the hole is normal. I decked a block .030 once and it was still 55 in the hole. But, between that and a steel shim head gasket that should be close to 9.0:1. Decking a block isn't too cheap though unless the motor is going to be apart anyway.
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