1986 109 block stock piston dish cc?

[hotairgnx548]

Can anyone tell me what the cc is on a stock piston dish in the 109 turbo buick v6? Trying to figure the compression ratio on my new build. Thanks hotairgnx547

 

[charlief1]

23.6 CC dish according to my books.

 

[hotairgnx548]

Charlie thanks for the reply. I used a graduated beaker with water in it and as close as I could figure it took between 27& 28 ml to fill the top of the dish. The machine shop that does my work with out checking it with a syringe said one of their books says 27 the other says 28 the difference is on my build a 8.88 to1 or a 8.98to 1 compression ratio. Thanks again Charlie. John Bruce

 

[charlief1]

You might wait until some of the others chime in here before you say yea or nay though John. My books are a little old but they are GM written and I'd like to make sure it's right. I also don't know the conversion from ML to CC's.

 

[bison]

23-24cc. .060 in the hole with stock deck height

 

[bison]

You might wait until some of the others chime in here before you say yea or nay though John. My books are a little old but they are GM written and I'd like to make sure it's right. I also don't know the conversion from ML to CC's.

1ml=1cc

 

[bison]

Did you use a piece of glass over the piston and seal it with some grease? If not your number is no good because the fluid used to check will have surface tension and will rise above the top of the piston. It's not 27 or 28 if they are stock unaltered

 

[hotairgnx548]

Bison I had my 109 block decked .020 and now measure .046 average in the hole and with a 27cc its 8.98 and with 28 cc its 8.88 to 1. Maybe I need to get one of the pistons checked with a syrine and plate to be sure. thanks for the come back. John Bruce

 

[charlief1]

1ml=1cc

Didn't know that, thanks Brian.

 

[bison]

Without cutting the deck a lot changing pistons or stroke it's hard to get more than 8.3:1 with the stock pistons. Believe me I've tried it but it's a no go. The last one I did was 8.3:1 with .006 cut off the deck and a 45cc combustion chamber and .040 gasket

 

[bison]

Bison I had my 109 block decked .020 and now measure .046 average in the hole and with a 27cc its 8.98 and with 28 cc its 8.88 to 1. Maybe I need to get one of the pistons checked with a syrine and plate to be sure. thanks for the come back. John Bruce

You're missing something in the calculation. It shouldn't be that high even with .020 off the deck. I used 23.5cc on my stock one I just did and it was 8.3:1 for sure with 45cc gn1 heads

 

[hotairgnx548]

You're missing something in the calculation. It shouldn't be that high even with .020 off the deck. I used 23.5cc on my stock one I just did and it was 8.3:1 for sure with 45cc gn1 heads

3.840bore 3.40 stroke 40cc combustion .027 cometic h/g 3.84 gasket dia .046 deck 28cc dish I get 8.8 to 1 the pistons maybe hypers. The story goes with this engine 2nd owner blew it up and had 0ne of the engine companies build a crate eng for them its a 109 block with .040 over pistons. thanks John

 

[bison]

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3.840bore 3.40 stroke 40cc combustion .027 cometic h/g 3.84 gasket dia .046 deck 28cc dish I get 8.8 to 1 the pistons maybe hypers. The story goes with this engine 2nd owner blew it up and had 0ne of the engine companies build a crate eng for them its a 109 block with .040 over pistons. thanks John

I got the same. I'd question 40cc combustion chamber though. It would take a lot of milling to get them that small. You must have a special order head gasket too. .040" thick, 3.86" bore is typical

 

[hotairgnx548]

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I got the same. I'd question 40cc combustion chamber though. It would take a lot of milling to get them that small. You must have a special order head gasket too. .040" thick, 3.86" bore is typical

When I pull the head off and have the valve job I'll have the combustion chamber cc checked again. The head has been milled before and my records show it as 42 cc but when they put the 1.77 valve in it they said the cc would probalbly be closer to 40 cc do you agree with that? Thanks again. John

 

[bison]

When I pull the head off and have the valve job I'll have the combustion chamber cc checked again. The head has been milled before and my records show it as 42 cc but when they put the 1.77 valve in it they said the cc would probalbly be closer to 40 cc do you agree with that? Thanks again. John

they are probably closer to 46-47cc.