Author Topic: How much compression is too much?  (Read 1275 times)

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Offline Al Smith

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Re: How much compression is too much?
« Reply #10 on: December 26, 2011, 08:11:31 pm »
I don't know .They say 180 on a work saw .I have a d-handle on an 038 mag that tells you anything ,no problems .

Offline Troutfisher

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Re: How much compression is too much?
« Reply #11 on: December 26, 2011, 09:00:46 pm »
In my opinion yes, I have pushed compression over 220psi with a 2 piece head and it was the wrong way to go.  I think it hurts flow and remember you have to dead start the damn thing if you're gonna race it. And forget about doping the fuel......

Offline Cut4fun .

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Re: How much compression is too much?
« Reply #12 on: December 26, 2011, 09:08:50 pm »
Art what did you do besides the 246 piston install on the 5000 to get that kind of compression?  I have a stock one torn down I might put a 246 P in just to see how it is stock.
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Offline Old Iron Logging

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Re: How much compression is too much?
« Reply #13 on: December 26, 2011, 09:32:46 pm »
I put the 246 piston in and milled the cyl base to get .019 squish. Then raised the exhaust. We race over the block so start is not an issue. Going to try to get the 152 Efco into the same range.

Offline Troutfisher

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Re: How much compression is too much?
« Reply #14 on: December 26, 2011, 10:00:05 pm »
You must have pretty low exhaust timing to get that kind of compression? I read 240psi in the other thread?

Offline EHP

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Re: How much compression is too much?
« Reply #15 on: December 26, 2011, 10:13:34 pm »
how much compression really depends alot on how high your port timing is , follow me here , if you got a motor with 200 pounds of compression with a ext. port opening of we will say 85 degrees , it should live or be close to living in race forum on small wood, put that same compression on a motor with 92 degrees of opening on the ext. and she will get hot in just a couple seconds , If the port timing is quite high then 175 pounds is a safe number if running high test pump gas , This is on a low port motor  to start with, your transfers also have quite abit to do with getting hot fast

Offline Snoopy

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Re: How much compression is too much?
« Reply #16 on: December 26, 2011, 10:20:35 pm »
I have a 50 with a 490 top end with a 2 piece head running 220psi.

Offline Troutfisher

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Re: How much compression is too much?
« Reply #17 on: December 26, 2011, 10:24:33 pm »
holy crap, is that 50 a gas motor? pipe?

Offline Snoopy

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Re: How much compression is too much?
« Reply #18 on: December 26, 2011, 10:34:13 pm »
Its a alky-nitro stock appearing

Offline Troutfisher

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Re: How much compression is too much?
« Reply #19 on: December 26, 2011, 10:41:43 pm »
This 046 shows 140psi  ??? ............

http://www.youtube.com/watch?v=VVUOgA4m76I

 

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