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DIRTFUNFAN
03-28-2011, 12:57 PM
does anyone have a link to instructions of how the correct way is to pump test a motor for cc's?
circle track mag had a article on it a few years ago but i cant find it.. thanks

gadirtracer
03-28-2011, 10:20 PM
http://www.sportcompactonly.com/manuals/Brand/Mr.%20Gasket/3200.pdf

This is for C.I.'s not C.C.'s.
Not a 100% accurate way to check displacement, imo. I had a 355 pump 370 to 380 one night. My engine was the only one of the top five pumping big. Had to pull a head to prove legality.

gadirtracer
03-28-2011, 10:28 PM
http://www.speedwaymotors.com/pdf/550-3200.pdf

parrot69777
03-29-2011, 01:11 AM
The only way to prove true displacement is by actually measuring the bore & stroke. Too many tech guys don't have the time or facilities to pull an engine apart....let alone the smarts to do it right. Pumping an engine is only a guesstimate of what it really is. Engine temp plays a big part in this as well.

techracer44
04-04-2011, 12:48 AM
As a TECH OFFICIAL that uses a engine pump almost every weekend the only thing I can tell someone that is useing an engine pump is DO YOUR HOME WORK.

All of you guys know racers out there that will tell you what they are running for CID. Or you have someone you know that your friends with that races, and you know what they have for CID, USE there engine for testing.

The best way to test is with the Engine cold, you will be DEAD ON. If you Pump with the engine hot, Use a digital thermometer and wait as long as needed for the cylinder air temp to stop increasing, If you dont wait on the temp you will be wrong on CID. When you get to the engine to be checked, crank the engine first before you put the fitting in the plug hole to make sure there is nothing on the cylinder, when you have the hose hooked to the engine blow and suck on the hose to make sure the cylinder is tight and no valves are open.

Like I said though do your home work and test AN engine cold, get it hot and check the same engine, let it cool down and as it cools down keep checking it you will be amazed at how close you will be. One last thing, crank the engine untill the puck stops climbing in the tube or you will be small.

I have supprised a lot of racers how close I am when im done and we have a tear down rule at our tracks, so sometimes it easy to check just how close you really are.

Opps forgot something, no matter what REMOVE ALL THE PLUGS when testing (found this out by testing engines different ways with and with out plugs), and get a Photo tack and dont let the Cranking RPM go over 350 to 400 rpm. if it goes to high slow it down by jacking the rear up and putting it in gear when cranking or figure a way to slow the cranking speed down, you may have to push the car in gear, dont like to but it works.

Hope this helps.

gadirtracer
04-04-2011, 08:51 PM
Many racers up for pushing their car down a dusty pit/racetrack with the plugs out sucking dirt in the cylinders?:mad:
Shame on me for havin' a good starter!

stock car driver
04-04-2011, 09:09 PM
As a TECH OFFICIAL that uses a engine pump almost every weekend the only thing I can tell someone that is useing an engine pump is DO YOUR HOME WORK.

All of you guys know racers out there that will tell you what they are running for CID. Or you have someone you know that your friends with that races, and you know what they have for CID, USE there engine for testing.

The best way to test is with the Engine cold, you will be DEAD ON. If you Pump with the engine hot, Use a digital thermometer and wait as long as needed for the cylinder air temp to stop increasing, If you dont wait on the temp you will be wrong on CID. When you get to the engine to be checked, crank the engine first before you put the fitting in the plug hole to make sure there is nothing on the cylinder, when you have the hose hooked to the engine blow and suck on the hose to make sure the cylinder is tight and no valves are open.

Like I said though do your home work and test AN engine cold, get it hot and check the same engine, let it cool down and as it cools down keep checking it you will be amazed at how close you will be. One last thing, crank the engine untill the puck stops climbing in the tube or you will be small.

I have supprised a lot of racers how close I am when im done and we have a tear down rule at our tracks, so sometimes it easy to check just how close you really are.

Opps forgot something, no matter what REMOVE ALL THE PLUGS when testing (found this out by testing engines different ways with and with out plugs), and get a Photo tack and dont let the Cranking RPM go over 350 to 400 rpm. if it goes to high slow it down by jacking the rear up and putting it in gear when cranking or figure a way to slow the cranking speed down, you may have to push the car in gear, dont like to but it works.

Hope this helps.

it will turn over slower with 7 plugs in...........

techracer44
04-04-2011, 10:43 PM
stock car driver: You are correct it will tun over slower BUT, Im telling you if you do it that way you will be WRONG on the CID when you pump the engine. I know this as a fact.

Gadirtracer: I dont and wont turn this in to a I know more than the next guy post, But I would bet if you had a problem with your race car and could pull the intake off at the track and get it fixed so you could start on the front row of the feature: DIRT in your engine would not be a problem then, but let the Tech Man want to just pull the plugs out and all we here is OH MY GOODNESS I MIGHT DIRT IN MY ENGINE. All i can say is that is a SAD excuse.

SLM98
04-05-2011, 08:56 AM
He is correct about haveing all the plugs out,it can test big with seven in.