I'm looking into a used motor ... here are the compression results ...

125-125-130 (front rotor)
130-130-130 (rear rotor)

what do you guys think?

 

^^^

Anyone? Please?

 

Those numbers are amazingly good. Better than new in fact. I'd ****** that car right up. Factory "new" spec was 120psi (I'm assuming those numbers are psi), and the minimum spec is 100psi for '93, this was revised down to 85psi in '94.

 

I agree, those are very nice numbers for a used motor, how many miles does it have?

 

What is your RPM`s?

 

So do you think the guy is "stretching" the truth?

 

^^^

Anyone else have some advice they could share?

 

can anyone refer me to a sight of give some info on the best way to give a comp. test at home. i havent found anything with an rpm and how to keep it there. thanks.

 

Hey ... lets get my question answered first ... I'm strapped for time here.

And do a search on the web .... name it rotary compression test ... you'll find a bunch of sites that have "home" tests ...

 

thanks. sorry about that.

 

No worries ... I'm trying to find this out so i can tell this guy whether i want his engine or not.

Thanks for apologizing though ... good luck with your comp test. Most rotary shops will do em for cheap ... is there a shop near you?

 

nope. i live in tennessee. its chevy or giiet on outta heya!! haha. is the robinette website way good

 

yeah ... that site shows how you can do it ... he has a ton of DO-IT-YOURSELF-RX7 articles ... and has many links to other home rx7 mechanic sites.

Pretty cool

 

Still need an answer for the first question ... anyone able to shed some light?

 

One way of "stretching" the truth is to crank at higher than normal rpms. The test should be done between 200-300rpms, with 250 being the most common and the basis for stated tolerances. Higher rpms will produce higher numbers, and the shop manual's correction graph only goes between 200 and 300. Altitude also plays a role, but lower altitudes will create higher numbers and the tolerances are for sea level, so you can't really cheat with altitude. So, if he's not cranking at high rpms, either its a very good motor or he's simply lying, there's no other way to stretch.