cwasko

Hi... I recently picked up an 86 RX7 GXL from a guy I know. He had parked it because he said it felt like it was losing power more and more everyday. When I picked it up, it had been sitting for 2 years. I put on my booster pack hit the key and after about 15 seconds of cranking, it started and ran about long enough to get it half way on to the trailer.
When it was running it was smoking really badly. I know from most of the info I have read that these babys can run like crap and also flood real easy if not allowed to warm up.
My biggest ? right now is, how hard are these to rebuild, I know the fuel pump and all the usuall stuff that may cause power loss are ok, so I am assuming that my apex seals are taking a crap.
If I have to rebuild this thing, will a regular machine shop be able to machine the block part or what happens there? and are the rotors generally reusable?
So many ?s so little time.
Thanks in advance!!! Chris

dr0x

If you rebuild it before it pops, you can use a lot of the old parts. If you wait until it pops, you're buying some new ones. Obviously its cheaper to rebuild a motor before it blows up and causes more damage.

Anyways, do a compression test to be sure before you start throwing away your money.

hypntyz7

Welcome.

This could be because he had tried to start it at some point and was unsuccessful, and tried some oil/atf in the chambers to build compression back up. IT could also just be worn out oil seals.

Not very, but there are several itty bitty parts, and a few screw-up points along the way. With proper tools and work space, it can be done in a couple or 3 days.

There is no machining to a rotary, unless you go to the (generally unnecessary) expense of lapping side housings(irons, end plates). As such, there is no block like a piston engine. There are components that stack together to make what is referred to as the block, but they all seperate into small, workable parts, that cannot be machined. Whatever your rotors, rotor housings, and irons come out looking like, is generally what you have to rebuild. IF something is trashed, it must be replaced with parts from another engine. This is where the rumor got started that rotaries are not rebuildable; when they blow an apex seal it usually shatters at speed and destroys everything in its path, and those parts can not be reused. To make a good engine out of a blown one, you must take apart another engine and use half of it. Think of it as a piston block where each cylinder is detatchable.

Provided it hasnt already blown an apex seal or 3 (cracked, broken etc.) and damaged the internals, it should be fully rebuildable. Rotary bearings very rarely need replaced, as they are well lubricated and not under much stress in comparison with a piston engine. Rotors do not tear up other than apex damage, they just need cleaned really well. Rotor housings always have some irreversible wear on the compression surface (think cylinder bore) that cannot be machined or smoothed. THis is usually acceptable for the average rebuild. New ones cost $400+ each @ 2 per engine. Irons rarely need replacement, unless it is a high mileage unit (175k+) with heavy grooving, or has had cooling problems and suffered cracks/rusting of the coolant passages. Basically everything gets cleaned and checked for obvious defects and put back together. You can reuse many of the small seals and springs in th engine, that do not wear much at all. HEre is a list of my mandatory replacement parts, which I do not buy in a kit, but rather part by part to save money:

apex seals
corner seal plugs
rubber/viton oil o-rings
gasket overhaul kit, including internal o-rings
oil thermo pellet replacement(front of e-shaft/crankshaft), reliability mod

The following are not always necessary, but nice for a few extra bucks:

front and rear main seals
oil pump drive chain
corner seal springs
side seal springs

Everything else, barring breakage on teardown, is almost always reuseable.

Mr. Eccentric

Get to making that triangle sandwich!

Welcome to the forum.

Icemark

And please read this thread:

https://www.rx7club.com/forum/showth...threadid=59758