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-   -   Anybody had problems with p & g check (https://classracer.com/classforum/showthread.php?t=57679)

TOP GUN 04-20-2015 12:35 PM

Anybody had problems with p & g check
 
i had to pull a head after my engine pumped 6.5 cubic inches too big for the rules and 12 inches bigger than actual after head off check. a P & G check five years ago was accurate. differant machine!

Lyn Smith 04-20-2015 01:07 PM

Re: Anybody had problems with p & g check
 
new design starters and 16 volt batteries will crank them fast, and big!!!

Jim Caughlin 04-20-2015 01:29 PM

Re: Anybody had problems with p & g check
 
I wouldn't doubt that there could be variations between the P&G meters but my engine has always been dead on down to a fraction of an cubic inch when checked. That includes testing with both 12 volt and 16t volt starters.

Jim Caughlin
SS 6019

ss3011 04-20-2015 03:56 PM

Re: Anybody had problems with p & g check
 
Its important that the test is corrected for engine temperature.

Mike Taylor 3601 04-21-2015 09:47 AM

Re: Anybody had problems with p & g check
 
Like Lynn said if cranks too fast will pump big,had pulling customer pumped 481 with a 468
he had old delco hi torque with big dozer battery,they then pulled head and measured bore and stroke and could'nt measure stroke correctly they measured 4 1/4 so customer wanted to know if we could have ground crank wrong, no can't grind crank .010 and add 1/4 stroke,LOL ,we tested later would pump 481 could put in gear and let clutch out enough to slow cranking speed down would pump 468 then, when cranks too fast first hit of compression it blows the piston up farther than should.
Mike Taylor 3601

Adger Smith 04-22-2015 12:26 AM

Re: Anybody had problems with p & g check
 
My odd fire V-6 always checked big, until I started pulling all plugs and rockers and slowing it down with a 12 V-batt. Then it pumped right on. Part of my problem is I use a 142 tooth flywheel. like others have said. Temp and starter speed. The first "Hit of the puck" will usually set the ring.

RJ Sledge 04-22-2015 08:54 AM

Re: Anybody had problems with p & g check
 
PMS in San Antonio (Adrian Pendergrass) is the only one making them for the last 15 years or so, he builds them, sells them to everybody else (Power House, Comp Cams etc) and supplies all the Sanctioning bodies from NHRA, LSR, World of Outlaws, Nascar etc.

He'd be the one to answer your questions. 210-681-2405

RJ

FED 387 04-22-2015 11:01 AM

Re: Anybody had problems with p & g check
 
Question???-- are you taking ALL the spark plugs out of the engine and removing the push rods from the cylinder being tested????--we have used 12V/16V/24V starters to makes no difference- we get pumped regularly and never have had any problems as long as you correct for engine temp---- if there ever is a problem with one cylinder which RARELY EVER happens we move along to another cylinder still pumps accurately tho---we know exactly how big our engine is no guesses there--- never had to pull a head in the last 30 years--FED387

Adger Smith 04-22-2015 04:31 PM

Re: Anybody had problems with p & g check
 
What we determined was the Odd Fire/Odd valve action caused a "Jerk" in the rotation of the one cylinder that was being checked. It was worse with the cylinders that are on the short bank angle. The P&G has to have a smooth movement of the puck and it can't have any inertia movement to be done accurately. This happened after I set a record at Enis and Harold Hays and Wesley Roberson were checking it. The first thing that went wrong is Harold looked at the chart on the tube and said "This thing is 370" Cu In?? He was reading his V-8 line on his cheat sheet. Both Harold and Wesley couldn't believe that I was running an engine that was too big. They stuck with it and figured out the reason. A couple of sharp guys. They could have just walked away and told me I had to pull a head. All the years I ran a track Harold Hayes and I would do the P&G work. We only caught one guy that was too big, but had a couple refuse to P&G. If you don't clean the parts and store them right they will give you bad readings as they age. If a guy knows what he is doing he can nail it, but I think the instructions give you a 1% accuracy window.
BTY I had the same engine check another time and it was pretty small. I had a leaking Ex valve!!

TOP GUN 04-25-2015 02:19 AM

Re: Anybody had problems with p & g check
 
Thanks guys for the feedback.NO. 16 volt battereys { not needed to spank old chevys} don't shoot me adgar. but a 157 flxplate. 2 rockers off but pushrods sorta holding lifters n. 7 plugs left n. Tech official did comment on how fast he thought the cooling system bought temp down.Should have checked water temp quage for comparison. It seems b4 that it just stepped its way up to a reading n 2 to3 turns. This time straight up to 10 inches too big and about half inch more on the about 4 revolution. .My ford buddies {MD AP PJ} thanks guys. helped me remove a still warm head and th engine checked 3 inches smaller than the limit. but P & G protest 200$. cubic inch protest 700$ Maybe il win the next ace on the track.


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