80rx-7

someone, anyone, please help!! i know my way around a piston engine pretty good, the rotary is another story. i have asked people who own rx7s, the guys at the dealerships and just about every other tom dick and harry, i get too many different answers to my question so here goes. i recently bought my second 1980 rx7, the engine is a 12a but i dont know what year it is because the guy i bought it from said it was his third engine in 1 1/2yrs and doesnt know what it came out of. well the engine runs like total crap IF it runs at all. when it does run it has ABSOLOUTLY no power at all, it hesitates on acceleration, backfires like hell when you get off the gas and shakes more than a rotary should, as if the timing is off. its not i checked it and adjusted it and now the timing is dead on. the guy i bought it off of said "one day it was running like a champ, the next day it ran like crap." this is what he said(i think hes full of it personally) anyway ive been told low compression in one or both of the rotors,bad gas, rust or dirt in the gas tank,clogged fuel filter,bad plugs or wires,bad apex(i think they are called) seals..........the list goes on and on.now i know it could be ANY of these but what are the most common problems? please help because i need to get my baby running. thanks in advance!

hotty

mine had this problem a week ago - wouldnt rev over 3000rpm in gear, ... 4 new plugs and a fuel filter- runs great... maybe i got lucky. good luck

Papasmurf

I second that, I usually just take my plugs to the wire wheel and they work great, right after I did the MMO treatment, but I am still running on one rotor.

80rx-7

what is the "MMO treatment"? as you can see im a "exhaust leak", im new to this forum and not up to date on all the lingo yet.

jimmyv13

The MMO or ATF treatment dissloves carbon build up in the rotary. Use the search at the top of this page putting MMO or ATF as the subject. There have been hundreds of posts and you'll have all the info you need. Check back and let us know if you have any other q's.


BTW, have you had a compression check?

80rx-7

ok thanks. i havent done a compression test on it yet because i was unsure on how to do it. i read somewhere on here last night how to do it but i dont remember where it was. you have to take the valve out of a regular piston engine compression guage. does it matter what plug hole i use? top or bottom? then i should get three spikes of about 100 to 110. is that right?

yayarx7

just fyi its marvel mystery oil...

Yes....you take the little schrader valve out of the normal compression tester and remove one of the spark plugs on the rotor to be tested and crank er over. You should get three even bounces somewhere around the 100 mark. less if your engine is ported or older.

Good luck

80rx-7

ok thanks