Ptv clearence and compression ratio
01-10-2018, 01:57 PM
#1
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Location: Ofallon, IL
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Ptv clearence and compression ratio
So I have my stock Lt1 out of a Buick roadmaster.
I am wanting a lunati 60121 or cc306 cam. Will be getting afr 195s with 62 or 64cc combustion chamber in a month. Stock style gaskets. New timing chain and pushrods.
1.6 scorpion rockers.
Will I have any piston to valve.Clarence issues?
What kinda compression ratio would i get.
Again its a stock block for now. I will build a forged 383 in time so don't jump on me please.
I am wanting a lunati 60121 or cc306 cam. Will be getting afr 195s with 62 or 64cc combustion chamber in a month. Stock style gaskets. New timing chain and pushrods.
1.6 scorpion rockers.
Will I have any piston to valve.Clarence issues?
What kinda compression ratio would i get.
Again its a stock block for now. I will build a forged 383 in time so don't jump on me please.
01-28-2018, 09:08 AM
#2
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Re: Ptv clearence and compression ratio
I'm going to move this thread to “LT1 Based Engine Tech". Not a lot of traffic on Advanced Tech, and there is a request on the forum listing that advises not to use the forum for anything basic.
Much more likely someone will be able to help on the new forum.
Do you have the basic info required to do the CR calculation - piston valve relief cc's, planned head gasket thickness and bore diameter, deck height? Or should we just assume typical values for a stock cast iron head LT1 engine? Since the large combustion chambers may indicate you are eventually planning forced induction, would you want a gasket thicker than the stock iron head gasket?
Much more likely someone will be able to help on the new forum.
Do you have the basic info required to do the CR calculation - piston valve relief cc's, planned head gasket thickness and bore diameter, deck height? Or should we just assume typical values for a stock cast iron head LT1 engine? Since the large combustion chambers may indicate you are eventually planning forced induction, would you want a gasket thicker than the stock iron head gasket?
Last edited by Injuneer; 01-28-2018 at 09:10 AM.
01-30-2018, 12:48 AM
#4
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Location: Hell was full so they sent me to NJ
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Re: Ptv clearence and compression ratio
Looks like the cast iron specs. If you buy aluminum heads with the same cc's and use the same head gasket used on the cast iron LT1, you will get the same compression ratio.
Why replicate the Roadmaster specs? Buy a used pair of stock aluminum LT1 heads with 54cc chambers. I sold mine, which were the preferred casting # for $200. The aluminum heads handle the higher CR better than the CI heads.
Have them ported by someone like this, and have them recommend a matching cam based on your preferred performance and drivability requirements. You will end up with a lot more HP for less $$$ than buying a new set of AFR large chamber heads.
http://elliottsportworks.com/
The specs on the two cams you are looking at seem to be significantly different. Particularly with regard to a future 383 build. The Lunati cam is small for a 383.
Why replicate the Roadmaster specs? Buy a used pair of stock aluminum LT1 heads with 54cc chambers. I sold mine, which were the preferred casting # for $200. The aluminum heads handle the higher CR better than the CI heads.
Have them ported by someone like this, and have them recommend a matching cam based on your preferred performance and drivability requirements. You will end up with a lot more HP for less $$$ than buying a new set of AFR large chamber heads.
http://elliottsportworks.com/
The specs on the two cams you are looking at seem to be significantly different. Particularly with regard to a future 383 build. The Lunati cam is small for a 383.
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