Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: fd3spete on June 30, 2004, 05:03:39 PM

Title: compression testing
Post by: fd3spete on June 30, 2004, 05:03:39 PM
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?
Title: compression testing
Post by: MikeLMR on June 30, 2004, 05:13:14 PM
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
Title: compression testing
Post by: yonner on June 30, 2004, 06:01:30 PM
uc an use a normal comp tester on the rx7 u just need to be fast :P 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
Title: compression testing
Post by: Carl on June 30, 2004, 06:22:32 PM
8 bar is good,
6 bar is around the lowest that is reasonably ok for stock seals.
Kind regards
Carl
Title: compression testing
Post by: yonner on June 30, 2004, 06:25:05 PM
6 6 0 on my rear rotor :P i didnt even do front i jsut got confirmation that it was blown lol
Title: compression testing
Post by: MikeLMR on June 30, 2004, 06:30:19 PM
should just be a side seal then ?
Title: compression testing
Post by: fd3spete on July 01, 2004, 08:59:52 AM
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? :D