1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Determining year of motor

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Old 05-19-11, 06:06 PM
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vrrmmmmm

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Determining year of motor

I have a 12a, but don't know if it's an 81-83 or 84-85.

I have one motor I'm pretty sure is an 82. The rear plate has a Y at the top and a 2 at the bottom. It also has 1 coolant passage under the oil pressure sender.

The motor I'm unsure about also has 1 coolant passage under the OPS, and the rear Iron says Y at the top and l at the bottom.



here is the passenger side of the unknown motor.

Here is the oil pedestal that is on it.



I'm trying to install a racing beat aluminium flywheel with a 225mm clutch.
Old 05-19-11, 06:24 PM
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need more pics!

1st pic is an 81-85 engine. its hard to see, but the casting by the turbo oil drain *might* make it an 84-85, but pic isn't good enough

2nd pic is a 1968-1981ish oil filter pedestal. the oil filter pedestal fits every rotary engine up to the rx8 motor, so its not a good way to date the engine.
Old 05-19-11, 09:47 PM
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Old 05-19-11, 09:49 PM
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I think it's an 81-83?

I have an aluminum flywheel I was going to mount using the 81-83 rear counterweight with a 225mm clutch and pressure plate.

Is that correct?
Old 05-20-11, 10:12 AM
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btw: flywheels are not 81-83 and 84-85. They are 74-82 and 83-85. I'm not sure what year motor it is though. all I can tell is it is a 81-85 motor. You should be able to use the newer flywheel with an older counterweight.
Old 05-20-11, 11:44 AM
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Front cover is an 84-85. It has a 12Aturbo oil return casting. But front covers can be swapped.

Did anyone notice the oil filter pedestal casting appears to have been broken off and repaired. Interesting. So that's probably a beehive rear plate making it a possible 83-85 engine.

The heater core fitting doesn't seem to be a T like a beehive engine is supoosed to have, but they can be cut off. I've had to do this myself in a cramped engine bay, so you gotta take the hose off to see if there is a nipple.

Also notice below the heater core fitting. There is a bit of blank iron casting kinda sticking out. I think all beehive rear plates had this. The earlier Y plates aparently didn't.

I'd say there is a good chance you've got an 84-85 engine there. The front cover, if original, proves it.

So get yourself an 83-85 rear counterweight. Then you can use your aluminum flywheel and 225mm etc.

One word of warning. That engine was left out in the rain so drain the oil and make sure it spins freely. Also clean off the surface rust from the shaft.
Old 05-21-11, 12:16 AM
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Originally Posted by Jeff20B
Front cover is an 84-85. It has a 12Aturbo oil return casting. But front covers can be swapped.

Did anyone notice the oil filter pedestal casting appears to have been broken off and repaired. Interesting. So that's probably a beehive rear plate making it a possible 83-85 engine.

The heater core fitting doesn't seem to be a T like a beehive engine is supoosed to have, but they can be cut off. I've had to do this myself in a cramped engine bay, so you gotta take the hose off to see if there is a nipple.

Also notice below the heater core fitting. There is a bit of blank iron casting kinda sticking out. I think all beehive rear plates had this. The earlier Y plates aparently didn't.

I'd say there is a good chance you've got an 84-85 engine there. The front cover, if original, proves it.

So get yourself an 83-85 rear counterweight. Then you can use your aluminum flywheel and 225mm etc.

One word of warning. That engine was left out in the rain so drain the oil and make sure it spins freely. Also clean off the surface rust from the shaft.

The 1/4"npt threaded hole under the omp is something that I drilled and tapped to be used as an oil return line for my turbo.

Here is a close up of it.




Is the heater core fitting under the oil pressure sender?

I have both a 79-82 and 83-85 so I just need to determine which to use. Is there anything special that needs to be done to install it? The clutch and pressure plate are both 225m and its the racing beat alumium flywheel.

It wasn't left in the rain but it was left in my storage shed at my apt and then in my moist garage while I got around to installing it. I've tested the motor by spinning it and it feels and sounds good.

When I removed the waterpump housing and the waterpump there was a pocket of solidified coolant though. Hopefully my coolant passages aren't in the same condition. Is there anything I can do to flush it before installing the motor?

It was advertised as a streetported 12a and I'm not confident that it actually is.

Thanks for your help Jeff20b
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