I am going to have to flycut!!! :(
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
Finding out exactly what it "should" be has been a crap shoot.
I too have wondered about dynamic compression ratio with this small of cam. If it was 23x/23x or 23x/24x I don't think it would be an issue.
I just looked at my DCR calculator and if each flycut = 1 cc @ 59 cc combustion chamber you will have 8.72:1 DCR with 11.27:1 static compression ratio using a gm MLS gasket. Sounds about perfect to me, you got it right. Have those heads milled around .033" and you should be set, just make sure it doesn't cause alignment issues with the intake.
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
I just looked at my DCR calculator and if each flycut = 1 cc @ 59 cc combustion chamber you will have 8.72:1 DCR with 11.27:1 static compression ratio using a gm MLS gasket. Sounds about perfect to me, you got it right. Have those heads milled around .033" and you should be set, just make sure it doesn't cause alignment issues with the intake.
No problem man, as you can see from my results when you take the time to do things right it will pay off. I run about 8.8:1 DCR on our 92 octane fuel with the TR-6 plugs and have no issues what so ever. Throttle response will be nice and crisp with good lowend torque, which a lot of setups online lack. Have fun with it when you get it all done 
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
I "hope" to have over 400 ft lbs at the tires. I have been conservative on my build and tried not to get sucked into the bigger is better category.
I am sure I could pick some power up with a few parts. FAST intake, 1 7/8 headers, EWP....
To me, the cost is not worth the "gains". However I did buy a 85mm MAF and a Fast Toys 98mm lid so maybe I am an idiot.
But on a stock rear car with 275 tires, is it really going to matter? Personally I don't think so.
I am sure I could pick some power up with a few parts. FAST intake, 1 7/8 headers, EWP....
To me, the cost is not worth the "gains". However I did buy a 85mm MAF and a Fast Toys 98mm lid so maybe I am an idiot.
But on a stock rear car with 275 tires, is it really going to matter? Personally I don't think so.
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
I got the drivers side done tonight. It took a while but wasn't as bad as I thought it would be. I cleaned the notches with some 150 grit paper trying to take the sharp edges off. I will do the passenger side tomorrow. I ran out of beer and the bugs were getting to me tonight.
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
I never got to check the exhaust clearance before I took the heads to get them milled. I had to cut the intake to even get the new heads on the block. I cut .100 on the intake and about .090 on the exhaust. I know I will be giving up a little compression but I became impatient tonight and at the time it seemed like a decent idea. I got so wrapped up in the problems I was having with the intake side I totally forgot about the exhaust.
I will have plenty of clearance for any cam I should put in there in the future. Which I hope I never do.
I will have plenty of clearance for any cam I should put in there in the future. Which I hope I never do.
Last edited by LilJayV10; Jun 21, 2010 at 12:12 PM.
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Verdad Gallardo Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
That's one way to look at it. My thinking at the time was they dropped the exhaust valve down like the intake, which I don't know one way or the other. If I end up with .300 clearance on the exhaust side I will know I was wrong.
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
I have .097 on the intake now after cutting .100 and after having the heads milled to 59cc. I have AMPLE exhaust clearance.
I really wish I would have waited and not cut the exhaust notches. I'm an idiot, I should have waited.
I am thinking about using the .040 cometic gaskets to help band aid my screw up. Even with the thinner gasket I will be way within the safe area.
Any ideas?
I really wish I would have waited and not cut the exhaust notches. I'm an idiot, I should have waited.
I am thinking about using the .040 cometic gaskets to help band aid my screw up. Even with the thinner gasket I will be way within the safe area.
Any ideas?
I have .097 on the intake now after cutting .100 and after having the heads milled to 59cc. I have AMPLE exhaust clearance.
I really wish I would have waited and not cut the exhaust notches. I'm an idiot, I should have waited.
I am thinking about using the .040 cometic gaskets to help band aid my screw up. Even with the thinner gasket I will be way within the safe area.
Any ideas?
I really wish I would have waited and not cut the exhaust notches. I'm an idiot, I should have waited.
I am thinking about using the .040 cometic gaskets to help band aid my screw up. Even with the thinner gasket I will be way within the safe area.
Any ideas?
trust me it isn't not affecting your compression much at all I measured my flycuts at .110 for both and it came to 1.2cc total...and the exhaust is smaller than the intake...so cutting the exhaust affected your cc by like .4cc which is like nothing...your compression ratio was only affected by hundreths...not even 1 hp...
figure you jump from 10:1 to 11.5:1...and each point is worth around 3%...say you put 450rwhp down...so 3 percent is 20hp...each tenth of a compression point is worth 1.3rwhp...
that make you feel better
don't split hairs...just put 1psi more in your tires
oh and I have .160 clearance on my exhaust...
figure you jump from 10:1 to 11.5:1...and each point is worth around 3%...say you put 450rwhp down...so 3 percent is 20hp...each tenth of a compression point is worth 1.3rwhp...
that make you feel better
don't split hairs...just put 1psi more in your tires
oh and I have .160 clearance on my exhaust...
Thread Starter
Joined: Apr 2007
Posts: 9,716
Likes: 999
From: Evansville,IN
trust me it isn't not affecting your compression much at all I measured my flycuts at .110 for both and it came to 1.2cc total...and the exhaust is smaller than the intake...so cutting the exhaust affected your cc by like .4cc which is like nothing...your compression ratio was only affected by hundreths...not even 1 hp...
figure you jump from 10:1 to 11.5:1...and each point is worth around 3%...say you put 450rwhp down...so 3 percent is 20hp...each tenth of a compression point is worth 1.3rwhp...
that make you feel better
don't split hairs...just put 1psi more in your tires
oh and I have .160 clearance on my exhaust...
figure you jump from 10:1 to 11.5:1...and each point is worth around 3%...say you put 450rwhp down...so 3 percent is 20hp...each tenth of a compression point is worth 1.3rwhp...
that make you feel better
don't split hairs...just put 1psi more in your tires
oh and I have .160 clearance on my exhaust...
I talked to some people today much smarter that me and I decided I should listen to them. Refer to my build thread as I am saying, a loose quote, "I am not one of those people who call someone who knows what they are talking about and does something different."
After flycutting with one of the GM MLS gaskets with the stock heads it had junk all over it and no way was I going to use it in my final build. In a late drunkin order I ordered a set of cometic gaskets and one GM gasket from John@SDPC last night because I didn't know which route I was going to take.
The local dealership had "ONE" of the head gaskets in stock and I had to give them a part number. It was like talking to Auto Zone. So I picked it up and torqued the bastards down tonight.
I thank everyone that has helped me through this. This is my first LS build and I have checked more things on this build than any car I have done before.
