Rotary Newbie
11-24-17, 10:17 AM
#1
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Rotary Newbie
Hey guys, new to the forum and rotaries in general. Straight to the point, there's a guy that wants to sell me a 12a for 300 bucks. He said its disassembled entirely so theres no way to see if it starts obviously. Is it worth it? What should I be looking for? Anything I should know? Appreciate it!
11-24-17, 11:39 AM
#2
Since it disassembled, there are procedures for measuring the irons and housings to determine if they are in spec.
This is for a 1979 but it will help regardless of 12A year.
http://foxed.ca/rx7manual/manuals/Ro...ria%201979.pdf
This is for a 1979 but it will help regardless of 12A year.
http://foxed.ca/rx7manual/manuals/Ro...ria%201979.pdf
Last edited by KansasCityREPU; 11-25-17 at 08:58 PM.
11-26-17, 12:19 PM
#5
Ironically ( in a good way) - having a dissected rotary to eyeball is possibly a BETTER way to determine if its still OK. As noted by KC-REPU, you can now actually LOOK at the engine at the component-level to see its condition. Rotaries can still be failing, even if they start and run, with no one being the wiser until a tear-down. Now you need to bone-up on just what to look for in making The Call to buy it...
There is a "List" and maybe others will chime in on what too check. here are a couple of easy ones:
-check the side edges of the surface of the rotor HOUSING (the aluminum section the rotor spins in). These tend to have the chromed surfaces "flake" off at the edges. If this is too far gone, it ruins the engine's ability to compress properly. These surfaces can sometimes be "corrected", but at some cost. Minor flaking is inevitable with use, its a question of degree. Post some pics of the housing surfaces and we can offer an opinion...
-excessive scoring on housing combustion surfaces (either the aluminum combustion housings OR the faces of the Iron side housings) is bad. If your thumbnail can catch an "edge" its likely either too far gone, or again, some $$ resurfacing will be in order.
It also means you - or someone - will need to re-assemble the motor. This is actually not as difficult as, say, a piston engine, tho there are specific methods. There are some excellent "How to rebuild Rotary Engine" videos out there, starting with the one produced by mazdatrix. Now the caveat here is, you need to be SURE the seller has ALL the pieces!!! A motor in a box, can be problematic if you don't know what is missing...
Best of Luck. Great knowledge base here. Ask lots of Qs!
Stu Aull
80 GS
AZ
There is a "List" and maybe others will chime in on what too check. here are a couple of easy ones:
-check the side edges of the surface of the rotor HOUSING (the aluminum section the rotor spins in). These tend to have the chromed surfaces "flake" off at the edges. If this is too far gone, it ruins the engine's ability to compress properly. These surfaces can sometimes be "corrected", but at some cost. Minor flaking is inevitable with use, its a question of degree. Post some pics of the housing surfaces and we can offer an opinion...
-excessive scoring on housing combustion surfaces (either the aluminum combustion housings OR the faces of the Iron side housings) is bad. If your thumbnail can catch an "edge" its likely either too far gone, or again, some $$ resurfacing will be in order.
It also means you - or someone - will need to re-assemble the motor. This is actually not as difficult as, say, a piston engine, tho there are specific methods. There are some excellent "How to rebuild Rotary Engine" videos out there, starting with the one produced by mazdatrix. Now the caveat here is, you need to be SURE the seller has ALL the pieces!!! A motor in a box, can be problematic if you don't know what is missing...
Best of Luck. Great knowledge base here. Ask lots of Qs!
Stu Aull
80 GS
AZ
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11-26-17, 01:59 PM
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Well as I said Im really wanting a rotary in my E30. 13b from what I understand is the best of the rotaries. I dont mind putting in a little work to get one that needs a rebuild and itll be a learning experience. Ant suggested paths I should go and where to start? Where to find one?
11-27-17, 02:55 AM
#11
Check if the rotor housings (there are 2 of them and theyre the silver ones) are in good shape. If there is no flaking on the smooth chrome surface on the inside, you might consider picking them up anyways. Good condition 12a rotor housings are getting rare!
edit: saw the pictures. They do look pretty rough. I think id pass too.
edit: saw the pictures. They do look pretty rough. I think id pass too.