Deck Height
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Deck Height
Can someone explain what deck height is and how to measure it.
I would like to caculate my compression ratio for the current set
up I have and what it would be with different heads.
I would like to caculate my compression ratio for the current set
up I have and what it would be with different heads.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by Oldguard 7
Can someone explain what deck height is and how to measure it.
I would like to caculate my compression ratio for the current set
up I have and what it would be with different heads.
I would like to caculate my compression ratio for the current set
up I have and what it would be with different heads.
i'm out of town and i can't reference this....but since no one is chiming in i think its the distance between piston TDC and the top of the cylinder block....where the gasket would go in between head and block....measure it by moving piston to TDC and put a straight ruler across the cylinder and measure down....then use a volume formula to calculate volume...something llike distance x diameter (check this formula can't remember for sure) then you take head volume and add something for gasket thickness apply a formula an voila you have an answer....clear as mud.....
Senior Member since 1492
Joined: Aug 2000
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
If the piston is siting down in the cylinder, below the block deck, then the piston is "in the hole." That would be taken as a negative number....ie.. -0.005
Level with the block deck is "zero" (0) deck.
Level with the block deck is "zero" (0) deck.
Pro
Joined: Mar 2002
Posts: 511
Likes: 0
From: St. Louis MO
deck height is the distance from the crank centerline to the top of the block. This uses a special tool to measure it precisley. The other measurement you need is the length of the rotating assembly which is the 1/2 the stroke + connecting rod length + the compression height of the piston (distance from wrist pin centerline to top of piston)
You subtract these two dimensions and add the gasket thickness to get the quench height.
Typical Deck heights for the small block is 9.025 and the big block is 9.8. But you should have a machine shop check the deck and make sure its flat. They may have to cut a few thousands off the top which will affect your calculations.
Download this spreadsheet and enter everything in the that is colored yellow, http://www.et-motorsports.cc/tech/en...uild_sheet.xls
Good luck.
You subtract these two dimensions and add the gasket thickness to get the quench height.
Typical Deck heights for the small block is 9.025 and the big block is 9.8. But you should have a machine shop check the deck and make sure its flat. They may have to cut a few thousands off the top which will affect your calculations.
Download this spreadsheet and enter everything in the that is colored yellow, http://www.et-motorsports.cc/tech/en...uild_sheet.xls
Good luck.
Le Mans Master
Joined: Mar 2004
Posts: 7,423
Likes: 1,458
From: Little Rock AR
The dimension you desire is measured with the piston at top dead center. You need to measure down from the top of the block to the top flat surface of the piston you are going to be using. This dimension is used to calculate static compression ratio. It can easily vary from one cylinder to another depending on the tolerance of all the pieces but you are striving to have them all the same.
-Mark.
-Mark.
