how to do a compression test on a rotary?

[MARKPRIOR]

anything different to a normal car?

how do i check compression across the tips

[David Nock (RIP)]

Never had to do one but I believe you have to use a special compression tester for the following reasons:
The chambers give a succession of pulses and the display on a normal tester will just show the highest pressure pulse, whereas you need all 3 readings on each rotor.
Second, and here\'s the rub, the tip on a normal tester may protrude into the chamber and break a tip seal.
In the past I\'ve just tended to use thumb over plug hole to try and sense any major upset between the 3 readings.
Perhaps anyone more in the know might like to add to this.

[MARKPRIOR]

argh ........

[Prof]

Good strong battery, and ideally you want to take it to a specialist - job only takes about 20 mins to do, they remove one plug form each rotor and put the tester in - then take the 3 readings from each.
 
You can sort of do the test yourself - you need a normal compression tester - but as Dave said - make sure it doesn\'t have anything that will go into the combustion chamber !  Most of the gauge testers have a small button or valve on the side - you need to hold that in, whilst someone cranks the enginve over - the idea is to try and read off the 3 highest readings you get.  Then repeat the test for the other rotor(s).
 
To do the test, ideally warm up the engine first.  Then remove the EGI fuse - this prevents the engine from trying to fire or inject fuel whilst cranking.  Have someone hold the throttle down (allows air into the chambers) and crank it over whilst the other person takes the readings.  Make a note of the RPM\'s you have when running the test - it will likely be just over 200 rpm - again a meter that can measure this might help.
 
Then you need to find 2 graphs in the Field Service Manual.  One shows how to correct the readings for altitude - to be honest it\'s unlikey this will need to be done unless you live on the moors.  The other table is more important - it shows how to adjust the readings for the RPM the test was done at.  The readings people always quote are adjusted for 250 RPM. If your test was at a lower RPM - which is likely - then you figures will be lower and need to be adjusted up.

[MARKPRIOR]

cheers, taking the car to Jurgen (JM-Imports) after he is back from his holidays and see where i go from there