Author Topic: engine compression  (Read 915 times)

Offline WVUFELLA

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engine compression
« on: April 05, 2006 - 07:49:39 AM »
heys guys i have a 440 bored .030 over .... How would I go about findign out the compression of the engine the guy ibought it off of said it was 12/1. It has a cam new pistons , rings, bearings, rockers, valves etc but how would i go about finding the compression. I called crane cams the other day to find out more about he cam he put in it and the guy told me I would need at least 10.5/1 to run that cam. I am trying to make a nice street car( granted i will run it hard sometimes here and there buyt i am not lookin to make a drag car out of it, I want a driver. How will i be able to tell if what he built is to much for the street?? or is there anyway to find out ? any help would be appreciated ... thanks if you need to know the cam numbers or any specs let me knwo




Offline 71383bee

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Re: engine compression
« Reply #1 on: April 05, 2006 - 08:21:57 AM »
Well if the engine is out or apart the best way to tellis to use a dial indicator and check the height of the pistons at TDC and get the heads cc'ed. 

You need to know the compression volume.

12:1 compression is HUGE by the way.  It will NOT run on regular pump gas if that is true.  You will need around 110 octane minimum. 

Hate to say it, but i call BS on that engine, especially if it's got stock heads.  I would expect a 12:1 motor to look like a funny car motor with external oiling, deep sump, etc.  If it looks like a plain jain 440 then I would be very warry.   
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Offline Chryco Psycho

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Re: engine compression
« Reply #2 on: April 05, 2006 - 01:31:47 PM »
are the pistons domed or flat ? is there a part # on the top of the piston ?
 I agree to measure the the distance form the piston to the deck , basically to get a real 12:1 compression it will need domed pistons , even the domed Speed Pro 2295 piston with closed chamber heads only gives you 11.4 compression

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Offline WVUFELLA

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Re: engine compression
« Reply #3 on: April 05, 2006 - 09:28:15 PM »
hey tanks guys Yeah my brother also called bull**** he even asked the guy if they ran pump gas thru it and he sadi yeah then my borther called him out by saying " well then if you run pump gas in it then it is not 12/1  well thanks for the info guess i have some work to do and the pistons are domed i checked on them today  thanks again