compression results
Thread Starter
Racer
Joined: Jul 2009
Posts: 344
Likes: 5
From: oak harbor wa
compression results
just one quick questions guys, witout using a borescope or pulling the heads what are the psitons flat tops or dish if the compression on all cylinders are between 170-180 what would be my compression ratio by the way im running the 882 heads
main reason i ask is because i was thinking of buying a procharger once the fourspeed swap is done and ive heard higher compression is not a good idea with a supercharger thanks in advance
mike
main reason i ask is because i was thinking of buying a procharger once the fourspeed swap is done and ive heard higher compression is not a good idea with a supercharger thanks in advance
mike
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
I don't think its possible to figure out the exact compression ratio without having in hand all the engine parts info., at most you can drop the pan and check the part number of the pistons and get its cc size, and even then you need to know the exact thickness of the head gasket because that would throw it out by as much as .5 point. the compression test will give you nothing at all, you may get low numbers but the static compression could be as high as 12:1 due to a high duration/overlap camshaft.
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
You could check if any shop around you has one of these.
http://store.katechengines.com/whist...ster-p174.aspx
They are supposedly very accurate. NASCAR uses machines like these to verify that the winning cars are in spec.
http://store.katechengines.com/whist...ster-p174.aspx
They are supposedly very accurate. NASCAR uses machines like these to verify that the winning cars are in spec.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
just one quick questions guys, witout using a borescope or pulling the heads what are the psitons flat tops or dish if the compression on all cylinders are between 170-180 what would be my compression ratio by the way im running the 882 heads
main reason i ask is because i was thinking of buying a procharger once the fourspeed swap is done and ive heard higher compression is not a good idea with a supercharger thanks in advance
mike
main reason i ask is because i was thinking of buying a procharger once the fourspeed swap is done and ive heard higher compression is not a good idea with a supercharger thanks in advance
mike
Just out of curiosity, you spend a lot of time texting on your phone, don't you?
Keep the shiny side up!
Scott
Thread Starter
Racer
Joined: Jul 2009
Posts: 344
Likes: 5
From: oak harbor wa
texting..
[QUOTE=scottyp99;1581202825]Stock compression is around 150-160 psi, so you've got something going on there, more compression than stock, anyway. Hard to say exactly what you got without taking it apart and looking at it.
Just out of curiosity, you spend a lot of time texting on your phone, don't you?
Keep the shiny side up!
Scott[/QUote
one of these days when i fall into some money i would like to do i a head swap so if that happens before a reason to pull the pan i will update and let you guys know what i found.
scott
I do text on my phone you are correct, but I wouldnt say alot, but when i am out and about i do use the corvetteforum mobile site to answer threads,
Just out of curiosity, you spend a lot of time texting on your phone, don't you?
Keep the shiny side up!
Scott[/QUote
one of these days when i fall into some money i would like to do i a head swap so if that happens before a reason to pull the pan i will update and let you guys know what i found.
scott
I do text on my phone you are correct, but I wouldnt say alot, but when i am out and about i do use the corvetteforum mobile site to answer threads,
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
[QUOTE=lowes-yellow77;1581203003]
I was just busting your chops, I know you get used to not using punctuation when texting, cuz it's a pita, but it still just looks kinda weird to old duffers like me. I actually have friends who give me the business for using punctuation and capitalizing letters when texting, but I can't help it!
Do you have any info at all on the engine in your car? If you're going to do a head swap, it's nice to know what your deck height is, piston style, and exactly what cam you are running.
Keep the shiny side up!
Scott
Stock compression is around 150-160 psi, so you've got something going on there, more compression than stock, anyway. Hard to say exactly what you got without taking it apart and looking at it.
Just out of curiosity, you spend a lot of time texting on your phone, don't you?
Keep the shiny side up!
Scott[/QUote
one of these days when i fall into some money i would like to do i a head swap so if that happens before a reason to pull the pan i will update and let you guys know what i found.
scott
I do text on my phone you are correct, but I wouldnt say alot, but when i am out and about i do use the corvetteforum mobile site to answer threads,
Just out of curiosity, you spend a lot of time texting on your phone, don't you?
Keep the shiny side up!
Scott[/QUote
one of these days when i fall into some money i would like to do i a head swap so if that happens before a reason to pull the pan i will update and let you guys know what i found.
scott
I do text on my phone you are correct, but I wouldnt say alot, but when i am out and about i do use the corvetteforum mobile site to answer threads,
Do you have any info at all on the engine in your car? If you're going to do a head swap, it's nice to know what your deck height is, piston style, and exactly what cam you are running.
Keep the shiny side up!
Scott
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Thread Starter
Racer
Joined: Jul 2009
Posts: 344
Likes: 5
From: oak harbor wa
Not a problem
[QUOTE=scottyp99;1581203132]
I was just busting your chops, I know you get used to not using punctuation when texting, cuz it's a pita, but it still just looks kinda weird to old duffers like me. I actually have friends who give me the business for using punctuation and capitalizing letters when texting, but I can't help it!
Do you have any info at all on the engine in your car? If you're going to do a head swap, it's nice to know what your deck height is, piston style, and exactly what cam you are running.
Keep the shiny side up!
Scott
i know its the the wrong block, numbers on front are V118TYZ, O5F120123 , i wiped a cam lobe a year ago and threw a cheap melling cam (MTC-1) just to get it back up and when i was in there the lifter vally looked brand new, but I am going to plan it out i don`t want to have to change parts over and over.
I was told engine was a 383 when i purchased car, but checked stroke with a wooden dowl and its just under 3 1/2 inch which is a 350 stroke, it does have roller rockers, gear drive, a full msd ignition system and all the aftermarket bolt on stuff, ie water pump(edelbrock),pulleys(billet), fan, headers, intake manifold (weiand stealth), carb(holley which i hate).
I may just borrow the borespcope from work it is a camera that will fit in a hole that is the size of a pencil or so, we use it to inspect the inside of aircraft engines and is actually good quality.
I was just busting your chops, I know you get used to not using punctuation when texting, cuz it's a pita, but it still just looks kinda weird to old duffers like me. I actually have friends who give me the business for using punctuation and capitalizing letters when texting, but I can't help it!
Do you have any info at all on the engine in your car? If you're going to do a head swap, it's nice to know what your deck height is, piston style, and exactly what cam you are running.
Keep the shiny side up!
Scott
I was told engine was a 383 when i purchased car, but checked stroke with a wooden dowl and its just under 3 1/2 inch which is a 350 stroke, it does have roller rockers, gear drive, a full msd ignition system and all the aftermarket bolt on stuff, ie water pump(edelbrock),pulleys(billet), fan, headers, intake manifold (weiand stealth), carb(holley which i hate).
I may just borrow the borespcope from work it is a camera that will fit in a hole that is the size of a pencil or so, we use it to inspect the inside of aircraft engines and is actually good quality.
Last edited by lowes-yellow77; Jun 30, 2012 at 09:40 PM. Reason: NEW INFO
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
That Melling cam is barely bigger than the stock L48 cam, so if you are running 170-180 psi on all cylinders during a compression test, you definitely have more compression than stock. Probably flat-top pistons. That's just a guess, though. However, someone who knows more about this kind of thing may be able to crunch some numbers now that your cam is known, and give you an approximate static compression ratio. I am going to guess at 9-9.5:1, which is nothing excessive. It's really just a guess, though. And not a very educated one, at that.
Keep the shiny side up!
Scott
Keep the shiny side up!
Scott