How important is it that a compression check be performed by a rotary specialist? Can a decent piston engine mechanic make the check and give reliable feedback? Also, what are good, acceptable, and un-acceptable readings for an 87 turbo. And lastly I did speak with a reputable rotary mechanic today and he indicated that TII rebuilds generally run about $2,500 to $3,000.
Is this accurate, it seemed like a lot of money but the guy has a pretty good reputation. All feedback appreciated. David

 

The reason they can't check your compression acurately at a normal shop is because the rotary requies a special tester that most normal shops don't want to invest in(about $1600, if I remember correctly). The rebuild price can fluctuate(sp) depending on what you want done what is damaged internally, and who does the rebuild. Shop around and see if there is somebody better and less exspensive than just the Mazda dealer near you. Since you're located in Florida then there is most likely a rotary specialist in your area or atleast close by

 

Yes. I have worked with rotaries for years and still use an autozone piston tester. You just need experience adn direction in interpreting the results.

IF you just want to get an overview of engine health, you can run a normal compression check on each rotor for a reading which represents the highest of the 3 faces per chamber, which is usually the same as the other 2.

IF the apex seals integrity are in question, youll need to hold in teh valve on the tester and observe the needle bounces. Uneven bounces or nonexistant bounces indicate broken/cracked apex seals requiring rebuild.

Even though different rotary models have different compression ratios, they should all generate the same pressure numbers. 90 is baseline acceptable, 100 is decent, 110 is good, and 120-125 is like new. An engine at 90 will have trouble idling well, inconsistent starting, and will usually die within a year.

That is fairly accurate. You can get a VERY good engine with modifications for that range. I can do stock and lightly modified rebuilds for around half that cost, $1200-1500 or so. Check out www.rotaryresurrection.com under FAQ and pricing for more info.

 

BTW:

https://www.rx7club.com/forum/attach...postid=1328586

 

thanks for the information, it is appreciated. David