compression testing

[fd3spete]

ive read somewhere that an ordinary compression tester cant be used on a rotary engine. is this true? if so why not? i do like to know the reasonbehind things and not just the answers. if it can, what sort of results are considered good or poor etc?

[MikeLMR]

because a normal compression tester builds pressure and then tells you the maximum achieved. Because the rotary engine has 3 chambers you want to be able to see the pressure for each chamber as it passes the plug ... hence why you need anvexpensive compression testing thingy.

can\'t remember what a set of good readings is but i\'m sure someone knows off hand

Cheers,
            Mike

[yonner]

uc an use a normal comp tester on the rx7 u just need to be fast hold the presure relies valve down and crank it over u will see the needel jump about the place it cranks over about 250rpm so u gotsa keep ur eye on it a good set of readings is about 7 psi i think but not shure all i know is that my readings wer not good

[Carl]

8 bar is good,
6 bar is around the lowest that is reasonably ok for stock seals.
Kind regards
Carl

[yonner]

6 6 0 on my rear rotor i didnt even do front i jsut got confirmation that it was blown lol

[MikeLMR]

should just be a side seal then ?

[fd3spete]

thanks for your help guys. anybody know how much one of these compression testers costs out of curiosity? might try and have a go with my ordinary tester while im changing the plugs today, might give me a vague idea. im sure its ok, just cant help playing with things. remember taking all your toys apart when you were a kid?