quick question, my grandfather gave me a compression guage that he had lying around, how am i supposed to test the compression? the headers get in the way, am i supposed to take the headers off to test the compression?

the reason I am testing is because I have 60cc chamber 305 heads on my 350, and I know that should get high compression, I just want to see how high.

thank you.

 

shouldnt have to pull the headers....

Take out ALL the plugs. Screw the fitting for the gauge into one cylinder, and crank the engine so it rolls over five or six times. Check the reading on that gauge. Move on to the next cylinder.

Not entirely sure what the actual number should be, but, all cylinders should be within about 10% of each other.

 

i dont know how I am gonna do it without taking off the headers thou, like the spark plugs barely fit under the headers.

 

If you have to take off the headers in order to hook up the compression tester, then do so. It won't change your numbers. It just adds work.

 

You could get a hose with the right fittings.

 

Disable the fuel and fire from the motor also.

 

yeah i know, I am gona remove the ignition coil and disconnect the fuel lines to the carb.


EDIT: I am supposed to hand turn the engine while someone holds the guage in the spark plug whole right?

 

If it doesn't have a screw in fitting, yep.

 

ok thanks guys!

 

Hand turn?
Use the key.

 

i meant like hand crank it.

but its ok to use the key to turn it over?

 

Don't have to disconnect the fuel lines.
Engine should be warmed up to get accurate readings but if your having time
issues between readings because of hookup time no biggie.

Open the choke on the carb with something while cranking, screwdiver
works good.

No spark a given.
HTH


Later

 

yeah, crank it with the key. unless you really need some exercise?

 

hold on, how can i warm up the engine, if theres no combustion how will the engine warm up?

and, if i disconnect the headers so i can fit in the gauge, will i have to worry about hot air coming out the exhaust ports and burning sh*t?

 

Like I said, if there is a problem with with time restraint because you
have to work around problems, no biggie.

But the correct way to do it is with a warmed up motor.
Exspansion, clearances, ect.

Warm it up before you start taking things apart.

Later

 

ok, someone mentioned getting a hose with fittings on it, where would i look for that?

 

Auto parts store would be the place to look first.

 

ok. thanks.