Compression testing

[Davegtt]

Is there a way of cheking the condition of the rotor tips when looking as a second hand car?

Can a normal compression test be done and what figures are expected?

Cheers

Dave

[Fish]

Dave, you will find a lot of information here!

Dan

[Davegtt]

Thanks alot matey.  I\'ve had a good read amd inwardly digested it

[Archbish]

Try getting one of them party blower things (you know, that unfurl when you blow through them)..

For each pound of pressure, the note changes up and down the scale (it\'s in the key of C, so ignore the black keys).

If you\'ve lost a tip, you\'ll hear  PPHHHTT - - , and if you\'ve lost a side seal, you\'ll hear PPHHHTT - PPHHHTT - .

I hope this helps.

p.s. as a further help, these party blowers can be modified so you can mount the spark plug directly into them, so you can test the engine at any time, simply by lifting the bonnet at idle and listening for the noises of the little buggers.  Of course, you\'ll have to drive off down the street going PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT - PPHHHTT, but that\'s a little cost for peace of mind.

[clive]

Hi Dave,

You need a Mazda compression tester to get 100% readings ,

However if you get a normal compression tester and hold the button in or remove the non return valve then get someone to turn the engine over and the needle will flick up and down and give you a guide.

Obviously you are looking for consistent readings and not one low one and then compare your readings to the other chamber.

There is a calculation that converts your reading into true compression from your Rotary but l am afraid l cant remember what it is , may be someone else will.  


All the best Clive
clive@mazdarotaryclub.com
//www.mazdarotaryclub.com

[Davegtt]

Right I think I get you,  Is this because the rotor is revoling and so you don\'t get a compression test for just one chamber like in a piston motor?  I guess if there is one rotor tip with more wear this wouldn\'t show up as you would get a reading from the higher compression chamber?

Dave

[clive]

Yep you got it .

Also refer to the section Danny sent you to though as it will help you with buying a car.

All the best Clive
clive@mazdarotaryclub.com
//www.mazdarotaryclub.com

[Davegtt]

Thanks alot I am trying to read as mucg info as Poss about these motors so I have some Idea of what I\'m up against.

I see Evo have never done a roadtest of one of these which is a shame

Any onther mags that have interesting articles etc?

This is a good site with lots of usful info and freindly chaps.

Dave