Re: CRANKING COMPRESSION
[Re: MIKES_DUSTER]
#868919
12/01/10 05:02 PM
12/01/10 05:02 PM
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Joined: Feb 2007
Posts: 5,080
organ
maximum entropy
master
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master
Joined: Feb 2007
Posts: 5,080
organ
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cranking compression is a good measure of the compatibility of a given combination. beyond that, it's not very useful as a diagnostic procedure. in school we had a 327 shivvie mule on a dyno that we conducted all manner of horrific and cruel experimentation. one of the pistons had a hole drilled in it (i think it was about 1/4 inch?). that cylinder had almost the same compression as the rest of them. learned a lot on that engine.
for what is the good life if not doing things thoughtfully?
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Re: CRANKING COMPRESSION
[Re: Dads426]
#868921
12/01/10 05:37 PM
12/01/10 05:37 PM
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Joined: Jan 2003
Posts: 9,146
Now - Port Orange,Fla. Former...
MIKES_DUSTER
OP
master
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OP
master
Joined: Jan 2003
Posts: 9,146
Now - Port Orange,Fla. Former...
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Thanks guys!!!! Hers the run-down on my combo. 360 balanced .040 (368") stock crank/rods ARP bolts KB-191's 12.3:1 comp. Ultradyne roller cam .556/.556 .285/.295 .249/.259@50 (1.5 rockers) J-heads flowed 284@.5252.02/1.60 1.6 Crane gold roller rockers M-1 ported 1" 4-hole spacer worked 850dp
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Re: CRANKING COMPRESSION
[Re: Labratt]
#868923
12/01/10 10:40 PM
12/01/10 10:40 PM
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Joined: Jul 2010
Posts: 184
Vernon Ct.
bp27
member
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member
Joined: Jul 2010
Posts: 184
Vernon Ct.
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12.3:1 comp. Ultradyne roller cam I do like Ultradyne Cams 
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Re: CRANKING COMPRESSION
[Re: Dads426]
#868924
12/01/10 10:48 PM
12/01/10 10:48 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
I would be more concerned about consistency between cylinders. Cranking pressure will depend on cam design and compression ratio. You can have 14-1 pistons and a ton of cam duration and the cranking compression will be low. Properly matching the components will result in the best combination. Don't know much about your combo, but 180-200 psi is very good. 
Yep.... I have 14.1:1 and only have 175 cranking compression
mainly due to the 112 lsa... but my engine never
see's lower than 5600 and thats the launch rpm
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Re: CRANKING COMPRESSION
[Re: MIKES_DUSTER]
#868928
12/02/10 12:57 AM
12/02/10 12:57 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
So,you think I can run pump gas(93-94) or will I have to mix race fuel with it?? If/when I race it,I will run straight race fuel. Was just asking for around town.
5600rpm launch????? LOOK OUT!!!!! 
Would depend on temp, quench, timing and IF you
truely get that octane... if you truely have 200
that MAY be a bit much... JMO
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