12a rebuild questions
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12a rebuild questions
1. Oil pressure mod- is crushing down the rear pressure regulator all that is needed for the 12a? I've read that brings psi up to about 90... Do I have to shim the front up as well? If so how much?
2. Do I need or should I change to a later model oil pump?
3. Flywheel- my engine is from a 1980, I have it's original flywheel plus another from a 1982/83... Any benefit from using the 82/83? If I swap due to lighter weight do I need to use the counterweight for the one I use?
Thanks
2. Do I need or should I change to a later model oil pump?
3. Flywheel- my engine is from a 1980, I have it's original flywheel plus another from a 1982/83... Any benefit from using the 82/83? If I swap due to lighter weight do I need to use the counterweight for the one I use?
Thanks
Last edited by 350xfire; 07-18-15 at 02:26 PM.
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OK, thanks for the info. I actually have a later 80's (82/83) model 12A and my 1980. The 1980 has a lot of chrome flake on the housings so I am using the later housings to rebuild it. So I figured if the later model oil pump and flywheel provide some upgrade I would use them on the rebuild.
Also, can any engine building machine shop re-surface our flywheels? What is expected cost for this?
I just placed an order through Atkins for my rebuild kit...
Also, can any engine building machine shop re-surface our flywheels? What is expected cost for this?
I just placed an order through Atkins for my rebuild kit...
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if i recall, the breakdown for 12A cars goes something like:
1979-80 - 215mm, something like 30 pounds
1981-82 - 215 mm, lighter than 30, but don't know the approximate weight off-hand
1983-85 - 225 mm, not sure on weight for these either
i believe the '81-'82 units can go on the SA engines with no consequence, but the '83+ will introduce issues.
there are a few posts floating around here, where you can get better info. search flywheel and use either Siraniko or J9fd3s in the criteria ... OR ... you can check Mazdatrix's site.
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the flywheels are thus:
76-82 rotors: which can be ID'd by the F or R stamp in the combustion recess, front or rear
79-80 flywheel, 30# feels like 300, you could keep an ocean liner from floating away.
81-82 flywheel, 23# perfect!
83-85 rotors: these are stamped in the combustion recess, the US rotors are NF and NR, for non turbo Front and non turbo rear. the turbo rotors are TF and TR
83-85 flywheel, 26# it is NOT COMPATIBLE with the 76-82 rotor weights.
76-82 rotors: which can be ID'd by the F or R stamp in the combustion recess, front or rear
79-80 flywheel, 30# feels like 300, you could keep an ocean liner from floating away.
81-82 flywheel, 23# perfect!
83-85 rotors: these are stamped in the combustion recess, the US rotors are NF and NR, for non turbo Front and non turbo rear. the turbo rotors are TF and TR
83-85 flywheel, 26# it is NOT COMPATIBLE with the 76-82 rotor weights.
Last edited by j9fd3s; 07-18-15 at 05:47 PM.
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