[QUOTE=yobtaf103;18756512]HD followed the after market with that? certainly more cost effective with the 20% discount applied 50 state EPA approved ! lol
I am using the CP Carrillo BHM8117-FT. They're rated at 10.75:1 compression, but that is with the stock .045" gasket. With the .030" head gasket it comes out to 11:1 +- depending on the chamber size. I had the heads milled today, took .012" off and I just cc'd them at 86 cc's each, so it came out perfect.
How did you come up with the .012" to get your 86 cc? Is there a formula for that too? My heads are off right now and I'm keeping them stock but looking for beneficial mods I can do to them. Thought about just having them decked for flatness.
How did you come up with the .012" to get your 86 cc? Is there a formula for that too? My heads are off right now and I'm keeping them stock but looking for beneficial mods I can do to them. Thought about just having them decked for flatness.
I had a draftman at work figure the area of the combustion chamber, it came out to 11.08 sq/in. If you multiply that by .010" to get the volume that you would lose by milling .010" off the head, it comes out .1108 ci. Multiply that by 16.387 to convert it to cc and you get 1.816 cc. Multiply 11.08 by .012 = .133. .133 x 16.387 = 2.18 cc. My heads cc'd at 88-89 cc's when I first checked them. Using Bigboyz calculator I figured 86-87 to be optimum for get 11:1 compression or slightly more. So I took .012" off each head and both heads cc'd at 86 cc's. I'm happy with it.
I had a draftman at work figure the area of the combustion chamber, it came out to 11.08 sq/in. If you multiply that by .010" to get the volume that you would lose by milling .010" off the head, it comes out .1108 ci. Multiply that by 16.387 to convert it to cc and you get 1.816 cc. Multiply 11.08 by .012 = .133. .133 x 16.387 = 2.18 cc. My heads cc'd at 88-89 cc's when I first checked them. Using Bigboyz calculator I figured 86-87 to be optimum for get 11:1 compression or slightly more. So I took .012" off each head and both heads cc'd at 86 cc's. I'm happy with it.
What thickness head gaskets are you going with? Measure PTV clearance ?
What thickness head gaskets are you going with? Measure PTV clearance ?
I'm going to use .030 Cometics. I haven't gotten to the point I would need to do PTV, but every time I have ever measured PTV on a Harley it has been more than adequate. I don't think any of the cams I would consider running have more than .500 lift.