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

Rebuilding for reliability (12a)

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Old Jun 2, 2008 | 12:57 PM
  #1  
well uhhh's Avatar
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Talking Rebuilding for reliability (12a)

Ok so first off, i have been searching for weeks and have a pretty good idea where i want to go.

I just tore down about a month ago, and pretty much cleaned everything up. The intermediate and rear side housings are shot (206k so it was expected.) From what Ive read, it always seems to be the rear. I don't want this to happen again, at least soon. Since i am buying new side housings, i want to do it right.

This is being built as a DD but that doesn't mean i wont drive the **** out of it. it will be a streetport, and i am leaning toward a sterling carb. I don't plan on spending a ton of time at 8k but it will happen. I would rather over-build than re-build.

Here's the plan: (motor olny)

streetport
hardened front stat gear
hardened rear three window stat gear.
new bearings all around.
se 17.5mm oil pump.
FC FMOC
shimmed opr?
E shaft jets?
ported oil gallies?

My question is this basically wether this stuff is necessary or extreme overkill. I dont have a huge budget but i will edit my budget to do it right. sorry if this is stupid/redundant, i have seen lots of conflicting info in my searches. Im an FC guy, I am just not to sure about the 12a mods.
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Old Jun 2, 2008 | 01:32 PM
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It isn't necessary, but it helps. You can also put on a S4 water pump, all you do is shim it down on one part.

You can do a stock rebuild and just streetport it, and it will be good.
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Old Jun 2, 2008 | 01:36 PM
  #3  
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My addition to your list is to mod the OMP to use an external two-stroke reservoir and run synthetic 0W-30 in the crankcase.
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Old Jun 2, 2008 | 01:38 PM
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well uhhh's Avatar
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jeezus, already have the housing and pump, should have added that!

Percent... i had thought of that but didn't list it, dunno why.

Thanks guys, keep it coming.

I was also curious, I read that the e-shaft jets are bad news for street cars due to low oil pressure at idle. Seeing as i am already upping the pressure so I sould be fine right? I dont do much stop and go driving, pretty much just GO!
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Old Jun 2, 2008 | 02:44 PM
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From: Huntsville AL
Originally Posted by well uhhh
jeezus, already have the housing and pump, should have added that!

Percent... i had thought of that but didn't list it, dunno why.

Thanks guys, keep it coming.

I was also curious, I read that the e-shaft jets are bad news for street cars due to low oil pressure at idle. Seeing as i am already upping the pressure so I sould be fine right? I dont do much stop and go driving, pretty much just GO!
The E-shaft jets open around 1500rpms. Most people put Weber 200 Air jets in the holes so it is constantly spraying oil. Since you are upping your pressure, you shouldn't have a problem with low pressure.
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Old Jun 2, 2008 | 02:49 PM
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+1 on the Sterling carb. Definitly a good choice for a DD. Good luck on your build.
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Old Jun 2, 2008 | 03:23 PM
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The FC FMOC will add life to the entire engine. Especially if this is a 83-85 that had the beehive. You didn't state the engine year, but the 83-85 rotors are lighter than the earlier models, so if you have an older engine, an update to the lighter rotors would be a good idea.
Don't know if you have it on the list and simply forgot to mention it, but a lighter steel flywheel would also be good for a DD.
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Old Jun 2, 2008 | 03:47 PM
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From: https://www2.mazda.com/en/100th/
here's my list...

start with NEW rotor housings.

find an 83-85 rotating assembly, with GOOD condition rotors, and balance it. lightening is ok, but optional.

hardened gears are needed for over 8500rpms, if you never rev it over 8, they arent needed.

fd oil pressure regulator, shim the front, fc or gsl-se oil cooler. use the oil pan baffle plate.

the eshaft oil jets are only needed if the things going to be full throttle all the time, which in a street car its not.

measure everything, and make sure its all in the good end of the tolerances.
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Old Jun 2, 2008 | 04:18 PM
  #9  
well uhhh's Avatar
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sorry i had edited it out on accident. Its an 85 gsl, rotors are looking good, but i havent put the micometer to them yet. Rotor housings are 66k miles, in good condition, very minor flaking. the side housings will be new with the exception of the front, which is still well within spec.

Does the FD OPR bolt right in? (well not bolt but you get it).

As far as the jets, they are cheap and my DD tends to get beat on a lot. A LOT! so i don't see it hurting anything. what would be more appropirate, atkins jets or the webers?

The hardened gears are just a precaution, i want the three window rear bearing so i may as well go three window stat gear, and the front to match.

This is all just my logic, if i am off, put me in my place. Thanks for all of the replies.
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