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-   -   Engine rebuild (What i need to know) (https://www.rx7club.com/1st-generation-specific-1979-1985-18/engine-rebuild-what-i-need-know-942581/)

Zentar44_ed 02-19-11 01:46 AM

Engine rebuild (What i need to know)
 
Im thinking about rebuilding my 12A oil starved (currently locked) engine. Was wondering what i need to do this job...would like all input if possible, i know rotating assembly, and bearings, and gasket kit, but where do i get these things? where do i find an e-shaft, and rotors that make balance spec... fyi i live in Arkansas i know 2 people that deal with these cars and they have never rebuilt one, i think i know more about em and im only 20...and both of them are mechanics lol....just some help guys is all i need...its either this or i scrap the car which i dont wanna do cuz it was my first car....

2jzgteRX7 02-19-11 03:30 AM

Good luck on your rebuild! Take your time and do your research so you get it done right the first time. There is nothing more frustrating than spending money and then having to go back and redo work and spend even more money, or even worse not be able to finish the project.

diabolical1 02-19-11 06:30 AM

do you know exactly what caused the oil starvation in the first place? you may want to take the necessary steps to prevent your new engine from suffering the same fate.

1. disassemble the engine, clean and inspect everything
2. check the classifieds and get your replacement rotors and shaft
3. have the rotating assembly balanced (i'm assuming you won't get a matching set in one shot) - that said, while not necessary if you do get a matching set (from the same factory engine), it's not a bad idea to balance it anyway, if you can afford it.
4. get your rebuild kit

only you can decide if you want to undertake the rebuild yourself. it can be done. however, if you're not up to it, or willing to chance a rookie mistake, then find a reputable shop. i don't know about Arkansas, but i know of a few in Texas

rwatson5651 02-19-11 06:58 AM

Before you dissassemble decide how you will organize the seals, you may be able to reuse these and if you do they will absolutely have to go back in the same place and oriented the same way, some places sale a special box to hold them but you can do it yourself. There are enough of them that they will get screwed up if you dont have some plan for organization.

Cleaning all the parts thouroughly is important as is getting the intermediate housings lapped.

Also you will need micrometers to mic everything with to see what is in spec and what is out and a set of telescoping gauges to check the oil clearences.

videos from either mazdatrix, pineapple racing etc would be very helpfull.

I just rebuilt my first one. I took my time so to avoid the rookie mistakes and so far it's running great.
Everytime it cranks I get a warm fuzzy feeling!

j9fd3s 02-19-11 12:20 PM

my procedure is similar to the two above,

1. pull it apart
2. clean clean clean
3. measure everything, there is a page in the back of the FSM (available here foxed.ca)
4. when you measure stuff, and compare to the factory spec, it makes it really simple to figure out what you need to order. since yours had an oil system failure, plan on an oil pump, eshaft and all the bearings
5. order parts
6. clean, paint etc
7. assemble without seals, ie mock up
8. assemble. not a bad idea to check the stuff that goes ON the engine when you're reassembling
9. enjoy!

my way takes a lot longer than some rebuilds, but i feel you end up with a better engine as you at least know everything is in factory spec.

Zentar44_ed 02-19-11 04:07 PM

Wow, this is going to be a long process...hopefully i can find a complete rotating assembly, because id probably have to send it off, ive only got about 1500 bucks to do this, so im on a tight budget...very tight, considering the last engine i rebuilt was a ford 302, and well thats nothing like these engines, except, constant measurements, and cleaning...ohh and what caused it to die was an oil-cooler line ruptured...

rwatson5651 02-19-11 04:20 PM

These are really much more simple than boingers!

Zentar44_ed 02-19-11 04:51 PM

hmmm, well ok first things first rotating assembly... is there any special one or something that goes in a 85 12A?

Jibaro 12A 02-19-11 07:08 PM

I found my rotating assembly on eBay. After I got all the components in I mailed the assembly to Atkins and had it balanced.

Jibaro 12A 02-19-11 07:10 PM

found you a eshaft buddy

http://cgi.ebay.com/ebaymotors/Mazda...Q5fAccessories

Jibaro 12A 02-19-11 07:11 PM

http://cgi.ebay.com/ebaymotors/Mazda...Q5fAccessories

found you some rotors. All you have to do is locate some counter weights....

trochoid 02-19-11 07:38 PM

Maybe you should let him find his own parts. These rotors are for an S1, he has an S3. And why does he need counterweights?

j9fd3s 02-19-11 09:25 PM


Originally Posted by Zentar44_ed (Post 10478131)
hmmm, well ok first things first rotating assembly... is there any special one or something that goes in a 85 12A?

the Eshaft is the same from 72-85.

the rotors are the same from 83-85, they should have an FN and RN stamp in the combustion recess. the 76-82 rotors are just F and R.

Zentar44_ed 02-19-11 11:17 PM

so do u guys think my rotors might still be good?

Jibaro 12A 02-20-11 01:44 AM


Originally Posted by trochoid (Post 10478327)
Maybe you should let him find his own parts. These rotors are for an S1, he has an S3. And why does he need counterweights?

Sorry for offending you just trying to help.

trochoid 02-20-11 02:04 PM

None taken, but I would be upset if I had bought those rotors on incorrect advice. Checking the op's profile can often eliminate such errors.

Jibaro 12A 02-20-11 02:25 PM

Word. I didn't take the time to check his profile.

Zentar44_ed 02-20-11 03:10 PM

hey i was tearing it down and went to take the flywheel nut off, and the motor broke free...

KansasCityREPU 02-20-11 03:14 PM


Originally Posted by Zentar44_ed (Post 10479393)
hey i was tearing it down and went to take the flywheel nut off, and the motor broke free...

Did you loosen the front eccentric shaft bolt also?

Zentar44_ed 02-20-11 03:16 PM

no i didnt loosen the front eccentric shaft bolt...

81WideMariah 02-21-11 01:41 PM


Originally Posted by Zentar44_ed (Post 10479393)
hey i was tearing it down and went to take the flywheel nut off, and the motor broke free...

Just because it broke free doesn't mean it won't need a rebuild. Likely the bearing just broke lose from the journal inside the rotor, so it's able to spin now. Put a flywheel stop on it and keep tearing it apart.

Zentar44_ed 02-24-11 03:05 PM

I cant get the flywheel off, i made a puller from 5/8" channel and grade 8 bolts, it bent in a u-shape, so i bought a flywheel puller, and broke an ear off it, so anyone have a suggestion...

KansasCityREPU 02-24-11 04:38 PM


Originally Posted by Zentar44_ed (Post 10487165)
I cant get the flywheel off, i made a puller from 5/8" channel and grade 8 bolts, it bent in a u-shape, so i bought a flywheel puller, and broke an ear off it, so anyone have a suggestion...

Here's the process. Other might have a better way.

1. Make a flywheel stop that bolts to at least two bolt holes on the back iron and one hole on the flywheel. Or some people will get a long metal flat bar and bolt it to two holes in the flywheel that can be placed on the ground.
2. Lossen the front essentric shaft bolt first before the flywheel nut.
3. Get a 2 1/8 inch (54mm) socket and a long breaker bar and lossen the nut
4. Put the nut back on a couple of turn. This is so that when the flywheel comes off, it won't fall.
5. Use a deadblow hammer and tap the flywheel around the outter edge staying away from the gear.

rwatson5651 02-24-11 04:46 PM


5. Use a deadblow hammer and tap the flywheel around the outter edge staying away from the gear.
+1
You want to make it "ring" like a bell without hitting it hard enough to damage it. Be sure not to hit the teeth or the outer ring. After three or four wacks it will come off.

[QUOTE. Put the nut back on a couple of turn. This is so that when the flywheel comes off, it won't fall.
][/QUOTE]

It will mash your toes !!!!

81WideMariah 02-24-11 06:46 PM

Then once you get it off... junk it and buy a lightweight flywheel and a counterweight.... much easier to deal with. ;)


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