How hard to rebuild 12a?
02-03-07, 10:17 AM
#1
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How hard to rebuild 12a?
I can get a 12a that needs a rebuild. I am thinking about it and would port it and mod it a little. Just how hard are these motors to rebuild. I know Dan Atkins has a vidieo on doing it. I would be in no hurry as the motor I have now has 20,000 on it and I dont wont to modify it. I am just kicking this around. What you guys think?
02-03-07, 11:56 AM
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How easy is it? how mechanically inclined do you have to be? master tech?, or just know what a wrench is. do you need any special tools? if so what are they? cause i am a mechanic and know everything about a 4 cylinder engine, but dont know how to rebuilt a rotary, but want to rebuilt mine. 
02-03-07, 12:51 PM
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12A Rebuild
Rebuilding a rotary engine is much easier than rebuilding your standard V8 and even easier than rebuilding an aircooled engine like a Corvair or VW. The videos produced by Atkins and some of the other big shops make it even easier.
I'd say rebuilding a rotary engine takes about as much effort as rebuilding a OHC head, although it does take longer time wise. Like some others have already said cleaning everything is the hardest part.
If this is the first time you've pulled an engine out of your car use a digital camera to take lots of pictures as to where everything goes. Also use alot of ziplock bags to hold all of the little parts and mark the bags so you know where everything goes. If you are really ****, like me, you can even write the number of the picture you took on the bag holding the parts for further reinforcement.
Hope this helps,
Peacedog
I'd say rebuilding a rotary engine takes about as much effort as rebuilding a OHC head, although it does take longer time wise. Like some others have already said cleaning everything is the hardest part.
If this is the first time you've pulled an engine out of your car use a digital camera to take lots of pictures as to where everything goes. Also use alot of ziplock bags to hold all of the little parts and mark the bags so you know where everything goes. If you are really ****, like me, you can even write the number of the picture you took on the bag holding the parts for further reinforcement.
Hope this helps,
Peacedog
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02-03-07, 03:29 PM
#8
Originally Posted by Peacedog94
Rebuilding a rotary engine is much easier than rebuilding your standard V8 and even easier than rebuilding an aircooled engine like a Corvair or VW. The videos produced by Atkins and some of the other big shops make it even easier.
I'd say rebuilding a rotary engine takes about as much effort as rebuilding a OHC head, although it does take longer time wise. Like some others have already said cleaning everything is the hardest part.
If this is the first time you've pulled an engine out of your car use a digital camera to take lots of pictures as to where everything goes. Also use alot of ziplock bags to hold all of the little parts and mark the bags so you know where everything goes. If you are really ****, like me, you can even write the number of the picture you took on the bag holding the parts for further reinforcement.
Hope this helps,
Peacedog
I'd say rebuilding a rotary engine takes about as much effort as rebuilding a OHC head, although it does take longer time wise. Like some others have already said cleaning everything is the hardest part.
If this is the first time you've pulled an engine out of your car use a digital camera to take lots of pictures as to where everything goes. Also use alot of ziplock bags to hold all of the little parts and mark the bags so you know where everything goes. If you are really ****, like me, you can even write the number of the picture you took on the bag holding the parts for further reinforcement.
Hope this helps,
Peacedog
The only thing you really need to do is to make damn sure you know where all the bolts come from.
Tools?
Dial Gauge and magnetic stand
Torque wrench (I used a $15AUD one)
the normal 8 through 19mm sockets + a 54mm one
a gear puller.
3ft+ of breaker bar for the flywheel and front hub bolts
I personally just paid a good shop to press the new rotor and stationary gear bearings, clearance the rotors sides (lathe involved here), and to port my housings and end plates, and to 3 window the rear stationary gear.
My personal opinion which was forwarded by one of my rebuild advisers (hes done a few before, and this was my first), is to always replace the entire oil pump, preferably with a mazda factory race one. I didn't and my highest oil pressure isn't much higher than about 4.0kg/cm3
02-03-07, 03:32 PM
#9
Make sure you have multiple editions of factory service manuals, as well as at least 1 rotary rebuild video. Talk to some people about personal choices, and choose a proven set of seals etc.
I used
Straight cut corner seals with RX-8 springs under them
RX-8 metal oil cages, but with early model oil rings
12AT apex seals with standard apex seal springs
standard side seals and springs, and standard oil seal springs
I used
Straight cut corner seals with RX-8 springs under them
RX-8 metal oil cages, but with early model oil rings
12AT apex seals with standard apex seal springs
standard side seals and springs, and standard oil seal springs
02-03-07, 06:57 PM
#10
simplest answer, buy the Atkins or Rotary Aviation bid, watch it several times and decide if you're up for the challenge. Is it hard, not really. I have never rebuilt a piston engine and after rebuilding a rotary, I don't know if I want to. Much more work and measureing involved.
Cleanliness, attention to detail and patience is the key. Rotors need to be spot on clean, expecially the seal grooves and test fit all of the seals and springs prior to assembly. Doing a good port is the hardest part of the build.
Cleanliness, attention to detail and patience is the key. Rotors need to be spot on clean, expecially the seal grooves and test fit all of the seals and springs prior to assembly. Doing a good port is the hardest part of the build.
02-03-07, 07:50 PM
#11
make sure to put in a lot of time in cleaning and massaging the oiling system, too. someone already mentioned the MFR oil pump, i used a hardened SE pump in my latest engine - either one would be a good move. clean the passages in the e-shaft and side housings, as well.
02-04-07, 08:48 AM
#14
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Thread Starter
Well the engine the guy told me about is not a 12a but a 13b and has had a conversion to holley carb. It has a stuck seal. The guy wants 400.00 and has the transmission, starter, injectors with rail and drive shaft. it is from a 86. Wont this convert to an 81 and is it worth that?
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