SLVRBLLT40 Posted March 4, 2008 Share Posted March 4, 2008 I just wanted to vent a little and say that I lazily didn't measure the combustion chamber CC's on my junkyard N42 head. Turns out it's been chopped .030 and I used a thin 1mm headgasket. I just built myself a 11.63:1 race gas engine with a stock cam, valves, and ports. D'OH! At least low end torque is super duper. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 4, 2008 Share Posted March 4, 2008 12-1 + is how I build all of my NA L series engines. 11.6 is faily mild. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted March 4, 2008 Administrators Share Posted March 4, 2008 I just wanted to vent a little and say that I lazily didn't measure the combustion chamber CC's on my junkyard N42 head. Turns out it's been chopped .030 and I used a thin 1mm headgasket. I just built myself a 11.63:1 race gas engine with a stock cam, valves, and ports. D'OH! At least low end torque is super duper. Hmmm... something isn't quite right here. Either the parts quoted, or missing info, or a typo. At least with what I understand of the L-6 and available pistons, head gaskets, cylinder heads, the info you posted above doesn't add up. What engine, what over bore if any, what stroke, what pistons, and what rods, are you using with this N-42 head? Regards, Paul Quote Link to comment Share on other sites More sharing options...
SLVRBLLT40 Posted March 4, 2008 Author Share Posted March 4, 2008 It's an L28, in which the pistons are flat tops that pop up .020 above the deck. I'm running a .040 (1mm) head gasket, and the N42 head that's been chopped .030. I typed in said specs to my compression calulator, with a 44.6 CC chamber, and then subtracted .030 from the head-gasket thickness to simulate a chopped head. I know it's not the proper way to do it, but I don't want to take th head off and CC the combustion chamber. Ah, and my cranking compression with all plugs out of the cylinders is 240 PSI across the board. Quote Link to comment Share on other sites More sharing options...
SLVRBLLT40 Posted March 4, 2008 Author Share Posted March 4, 2008 12-1 + is how I build all of my NA L series engines. 11.6 is faily mild. Do you run them on race gas or what's your secret? Quote Link to comment Share on other sites More sharing options...
jerryb Posted March 4, 2008 Share Posted March 4, 2008 The first engine I ever built was a 3.1L 11.5:1 L6. What a fun way to go...instant response, tons of torque. Loved it! But alas.....fuel was always a pain and I was retarding the ignition more days than not. Its wasnt worth the frustration and I ended up putting in a 2mm head gasket. Maybe an option for you as well? Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 4, 2008 Share Posted March 4, 2008 91 octane, 36 degrees full timing. Quote Link to comment Share on other sites More sharing options...
SLVRBLLT40 Posted March 5, 2008 Author Share Posted March 5, 2008 The first engine I ever built was a 3.1L 11.5:1 L6. What a fun way to go...instant response, tons of torque. Loved it! But alas.....fuel was always a pain and I was retarding the ignition more days than not. Its wasnt worth the frustration and I ended up putting in a 2mm head gasket. Maybe an option for you as well? Yeah, I know what you mean. I have my timing at 31 and it was pinging, but I put some 110 in it today and hazaah, it now hauls major ass. So I'm really really happy with it and I think I'm gonna keep running the non-sense money juice. Tomorrow I'm gonna try to advance the ignition to 34 or so and see how it does. Quote Link to comment Share on other sites More sharing options...
HizAndHerz Posted March 5, 2008 Share Posted March 5, 2008 I just got a new motor together and am in a similar situation. I rebuilt the bottom end with flattops and used a Felpro gasket set. I was going to rebuild a Maxima head but got impatient and threw on a nice-n-pretty N42 that someone else had rebuilt having no idea how much it was shaved. Heaven knows what the compression ratio is. My new motor pings on 91 octane with 32deg full advance. It sounds fine with 93 octane and 28deg. I've got to experiment so I can drive the car until the MN-47 is done. Quote Link to comment Share on other sites More sharing options...
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