12A rebuild
03-01-09, 07:33 PM
#1
12A rebuild
I blew an apex seal on my 12A that had 114k miles, and as my seven was my primary mode of transportation, I need to rebuild it soon. So I was wondering: what are the essential parts that I need for the rebuild? So far, I've come up with:
Rotor housings (which I already have. Thanks again Jeff20B)
Atkins rebuild kit (apex seals, springs, gaskets etc.)
Motor Mounts (I thought it would be a good idea to replace them while the engine's out)
If you guys could tell me if I'm forgetting anything, or if there is something I should look into that will increase the longevity of the engine, that would be great.
note: I was also thinking about getting the intermediate housings media blasted and resurfaced, but is this necessary?
Rotor housings (which I already have. Thanks again Jeff20B)
Atkins rebuild kit (apex seals, springs, gaskets etc.)
Motor Mounts (I thought it would be a good idea to replace them while the engine's out)
If you guys could tell me if I'm forgetting anything, or if there is something I should look into that will increase the longevity of the engine, that would be great.
note: I was also thinking about getting the intermediate housings media blasted and resurfaced, but is this necessary?
03-01-09, 07:43 PM
#2
"81 RX-7
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Do you have the main bearings & the rotor bearings, side seals & spring, corner seals & spring,oil springs & oil o rings,apex seals & springs? Might as well put everything brand new.
03-02-09, 01:01 AM
#4
You've got the biggest, hardest-to-find part : The rotor housings. 12a housings are getting harder to find by the day.
Good luck. Hopefully you won't need rotors or irons. Shafts tend to be the least worn parts since they're (ideally) separated from friction by the lubricant. So unless your car has ever run low on oil the shaft should be ok. And as long as the motor wasn't run too long after the apex blew you might not need to replace that rotor.
Good luck,
Jon
Good luck. Hopefully you won't need rotors or irons. Shafts tend to be the least worn parts since they're (ideally) separated from friction by the lubricant. So unless your car has ever run low on oil the shaft should be ok. And as long as the motor wasn't run too long after the apex blew you might not need to replace that rotor.
Good luck,
Jon
03-02-09, 03:29 PM
#5
As for longevity, of your engine, I would recommend new heater hoses, radiator chemically flushed. Flushing the gas tank is up to your discretion. I have heard that the chemicals can destroy the original coating inside but I suppose you can just recoat the entire tank after. I changed my pilot bearing and seal while my engine is out. As Joey mentioned earlier rotor bearings and main bearings should be replaced too since I believe you pretty much want to build a new or like new engine but not necessary if within tolerances. Pineapple Racing has some good info on tips to rebuilding your engine. The website is http://rebuildingrotaryengines.com/
Good luck
Good luck
03-02-09, 04:05 PM
#6
Actually, a number of professional rotary builders recommend NOT changing rotor and e-shaft bearings unless they show significant signs of wear or damage... as the most-common bearing failures happen during bearing break-in.
Get yourself a copy of the FSM, study it before your start. Having morethan one source, so you can contrast instructions, is also real handy. I found "How to Modify your RX-7" to be really helpful, first time I rebuilt a rotary.
You'll need access to some decent precision measuring tools, so you can check parts wear. Minimum of a micrometer (or a vernier caliper) able to cover 0"-2", inside diameter snap guage, dial guage and magnetic base for it, and a GOOD torque wrench. Access to a set of v-blocks for checking the e-shaft really helps, but you can pay a few bucks and get that done at a machine shop.
Until you tear down and check condition of seals and bearings, you really don't know what you're into, partswise. Your endplates may or may not need lapping/blasting depending on wear; at 115k miles the odds are about 60/40.
Get yourself a copy of the FSM, study it before your start. Having morethan one source, so you can contrast instructions, is also real handy. I found "How to Modify your RX-7" to be really helpful, first time I rebuilt a rotary.
You'll need access to some decent precision measuring tools, so you can check parts wear. Minimum of a micrometer (or a vernier caliper) able to cover 0"-2", inside diameter snap guage, dial guage and magnetic base for it, and a GOOD torque wrench. Access to a set of v-blocks for checking the e-shaft really helps, but you can pay a few bucks and get that done at a machine shop.
Until you tear down and check condition of seals and bearings, you really don't know what you're into, partswise. Your endplates may or may not need lapping/blasting depending on wear; at 115k miles the odds are about 60/40.
03-04-09, 05:16 AM
#7
Two items to consider, from Pineapple Racing (.com):
1) Their special Hi-temp water jacket O-rings, a weak part of these engines. Pricey, but cheap compared to leaks, overheating issues that stock -rings won't tolerate.
2) there neat water jacket pressure tester. Bolts to w/pump hole, allows you to air pressure test the newly-bolted up block to be sure no leaks betw water jacket and combustion chambers. Comes w/gauge, etc. $60 for great peace-of-mind on your rebuild prior to bolting up accessories and dropping her back in-
Stu Aull
80GS
Alaska
1) Their special Hi-temp water jacket O-rings, a weak part of these engines. Pricey, but cheap compared to leaks, overheating issues that stock -rings won't tolerate.
2) there neat water jacket pressure tester. Bolts to w/pump hole, allows you to air pressure test the newly-bolted up block to be sure no leaks betw water jacket and combustion chambers. Comes w/gauge, etc. $60 for great peace-of-mind on your rebuild prior to bolting up accessories and dropping her back in-
Stu Aull
80GS
Alaska
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