Pumping an engine to determine cubic inch

Old 05-07-2008, 02:01 PM
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dgordner
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Default Pumping an engine to determine cubic inch

This question is for those of you who have personal hands on knowledge of doing an engine pump to determine cubic inch. Just how accurate is it? If an engine is to be a 355 (chevy.030) and someone has a .060, just how precise is the pump? Give me a little language about what the proceedure is and what is being looked for. I think we are competing against .060 engines and the owner has threatened to do the pump on some of the guys. If the man doing the tech doesn't do it corrrectly, there is no sence in doing it.
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Old 05-08-2008, 02:08 PM
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billhendren
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If the tech man does the job exactly as it is suppose to be done it will be accurate within 2 CU.IN. The engine must have all the spark plugs out and the rockers removed from the cylinder in question. the P&G tube must be clean and dry,the engine is spun over on the starter and a reading taken.an accurate thermometer needs to be placed in the cylinder and the reading from the thermometer and the P&G then is adjusted by the temperature correction chart. Bill
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Old 05-08-2008, 04:45 PM
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dgordner
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Thank you Bill.
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Old 05-11-2008, 01:52 PM
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Tod74
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How much you want to bet they would most likely grab the number 1 cylinder for that test? Just a hunch but I think most of us probably would without thinking...so what if you bore all of em out except Number 1? :lol:
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Old 05-11-2008, 03:02 PM
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bbchevy
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Default Re: Pumping an engine to determine cubic inch

[quote="dgordner"]This question is for those of you who have personal hands on knowledge of doing an engine pump to determine cubic inch. Just how accurate is it? If an engine is to be a 355 (chevy.030) and someone has a .060, just how precise is the pump? Give me a little language about what the proceedure is and what is being looked for. I think we are competing against .060 engines and the owner has threatened to do the pump on some of the guys. If the man doing the tech doesn't do it corrrectly, there is no sence in doing it.[/quote

Can i ask you this?Are you Racing in a Class were your after a NATIONAL Record,or a hundreth or 2 seconds.
I think that you would realy be Surprised to fine out the Difference between your +0.30 Motor and Say His +0.060 Motor?
The Differences is Like Splitting a Hair(VERY SMALL)!!!
I would be more concered about a Compression RULE than 0.30 in bore!

About 10 years ago,i gave up on Drag Racing and went Dirt Toilet Bowl Racing.I have NEVER Seen so many Cheating Whining AZZZZHOLES!!
Anyway,they had this Compression Rule in the Class that we Raced in,and just as you say?They would always Pump #1 Cylinder???Well after a Long Drawn out conversation with the Tech Inspector?I was able to Sway the #1 Rule to a Random Cylinder Pump?
Seems that some the Front Runners had Flat-Top Pistons in #1?And the Rest were SAY Fit with a Bit MORE COMPRESSION?In other words #1 Flat Top=200lbs,but #2 Had 300lbs along with the other 6?Maybe it was just a Honest Mistake that the Builder made,or MAYBE NOT????
Later
G 8)
Now i have went Back to NOT Racing at All!I do Own a Car,just cant AFFORD to Race it?
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