piston question

K

KreagerM

Member

Nov 24, 2005

88

0

6

Maryland

Nov 24, 2005

#1

• Nov 24, 2005

• #1

Need some advice about pistons, compression and all that good stuff. Here is what I have. A 289 bored .030 over with silvolite 1157 dished pistons (http://kb-silvolite.com/spistons.php?action=details&S_id=106, stock heads in a C code 65 with a 2V carb. I guess I'm wondering what my compression would be with these pistons. I've searched all around and found the stock compression should be around 9.3:1 with stock pistons, but I wasn't sure if these pistons were the original design. Any help would be appreciated.

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

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37

Salt Lake City, Utah

Nov 24, 2005

#2

• Nov 24, 2005

• #2

It says that it is 8.2:1 compression but it does not give a size on the combustion chamber. That may be the ratio it produces on the stock 54cc combustion chambers. Which is very low I wouldn't do it, the minimum I would run would be a 9:1, 10:1 is right where I prefer it on a good reliable street motor. But that's my own preference, I like high compression.

 

rbohm

Founding Member

Apr 12, 2002

6,698

550

204

tucson,az

Nov 24, 2005

#3

• Nov 24, 2005

• #3

with 54cc combustion chambers, your compression ratio should be right around 9:1. i would go with a flattop piston instead. that should bump the compression to about 9.7:1.

 

K

KreagerM

Member

Nov 24, 2005

88

0

6

Maryland

Nov 24, 2005

#4

• Nov 24, 2005

• #4

I had a feeling it was a very low compression piston. I plan on getting a set of flat tops at the least. O'well looks like a nice winter project. Thanks

 

gonzothegreat

Member

May 4, 2004

421

1

16

London (uk)

Nov 24, 2005

#5

• Nov 24, 2005

• #5

that piston look familiar to what i have

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

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37

Salt Lake City, Utah

Nov 24, 2005

#6

• Nov 24, 2005

• #6

Those are factory style pistons.

 

D

D.Hearne

New Member

Sep 29, 2000

11,730

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south louisiana

Nov 24, 2005

#7

• Nov 24, 2005

• #7

Look at the part# 1195 Silvolites. These have a smaller dish and a taller comp height to get the comp ratio up where you want it. The 1157's and others have a 1.585 comp height that sets the piston top .025 down the hole at TDC, the 1195's put it right at zero deck with a 1.608 comp height.