MOPED ARMY

Good idea. It always bothered me how much 'loss' I knew was happening in that hose.

Thats what I use but I epoxied mine

Very nice, Thanks.

This makes so much sense and totally explains what I thought was a bizarre compression problem.

what mine looks like.

added to the wiki http://www.mopedarmy.com/wiki/Compression_gauge

though my wiki skills suck. someone should help me out

yeah.. i did some reading and i saw if you have two valves you should be good to go

my two piece tester had one schrader at the couple for pressure in and another schrader at the gauge for pressure out(when depressed of coarse). The first tube that screws into the head didn't have a schrader valve in it nor did it have threads for one. Therefore that first tube's volume between the head and first schrader(in the coupler) has to be added to the volume of the combustion chamber. Therefore what the gauge shows is lower than actual pressure with the sparkplug in.

Using one of the shraders with the light springs will give a more accurate test

so what kind of gauge is that called?

That's why they call it displacement. If your compression tester didn't max out that means you didn't crank the engine over long enough. If you cranked it over long enough and there was a difference in readings between using the hose and a more direct connection then the hose leaks.

Using full throttle, crank the engine over quickly as you can. On a ped that means pedal hard. Do that until the reading will rise no more. That is the cranking pressure of your engine.

will they blow out and screw up threads w/ out a release valve?

tim is talking about a gauge that has only one schrader valve and not two. Yes a single schrader valve gauge works just fine. The only thing is you have to unscrew the gauge to press on the single schrader to decompress the gauge instead of conveniently pushing on the second schrader valve on the side of the gauge to release the pressure. My gauge I made only has one valve. (edited)

I did that once, it didn't hold up very well but it worked for a year or so. probably right around the time this was originally posted - hmm

I kinda prefer tha hosey ones - i mostly just look at compression in a relative way, like oh i did this - now i have this.

my MAC brand one from about 150 years ago has the schrader valve in the base, it takes a few more revolutions to 'pump up' the hose, but eventually it levels off and that is dead on measurement.

i don't use it for performance stuff, though, because static compression is mostly useless in light of the pipe supercharge and other factors affecting dynamic compression... i just use it for checking rings and stuff.