bkm_rx7

So, i have this 12a motor with about 75,000 miles on it (what the seller told me) that i picked up for $100. It is a longblock with tranny and all...but all i want is the motor. My plan is to rebuild/streetport the engine myself, so i want to gather all of the information that may be necessary to do so correctly.

I guess what i WANT to know is the following...but feel free to throw in your two cents or any tips you may have about rebuiding, porting, or swapping a 12a motor.

1. What tools am i going to need to port my engine? (i have a die grinder)
2. What is the best way (cheapest, yet not bad) to go about porting/rebuilding my 12a?
3. What rebuild parts are totally necessary? (other than any that are bad...obviously)
4. What other things should be replaced when i swap motors? (clutch...etc...)
5. Does anybody have a more extreme porting template they would be willing to share with me than that of the racing beat template?

mazda6guy

iTrader: (1)

I just received my rebuild vid from Atkin's rotary and it is a must. Just for reference. I will watch it again and write down what is needed for a successful rebuild.

bkm_rx7

Well...dont stress yourself too much...bcuz i have that video...my brother used it when he rebuilt his 13b...but anyhow...im more looking for personal experience hints/opinions.

Hades12

Go to nopistons.com They have an entire porting forum, with lots of info from some masters of the Die Grinder.

Rx7carl

Judge Ito

bkm_rx7

thanks guys...b4 i head that direction...anyone wanna throw in their two cents?

SS124A

Ito, and Kahren, and Brian, and so on


I am building a similar 12A. I have an old template from Killer Bee Racing from the 80's. As well as Atkins, RB, and a couple other misc builders/Racers. I kinda collect them.

I spent some time today working out my oil-system.
which consists of e-shaft jets (2) 8553-11-411
17.5mm rotor width oil pump (stock on a few 12A's and GSL-SE cars) or 15mm pump from 74-78 12A.

either get the rear regulator RB 11812/4352-14-250


I can post my complete parts list for everything i need to order for the build

bkm_rx7

ss124a...do you have any idea how much your project is gonna cost you?

813KR$

Get all new springs behind your seals except the oil o rings in the rotors. If you can afford apex seals, new ones will seal better. Carbide bits cut well, just get a shape that looks small enough to fit good in the ports, but not to small unable to remove metal quickly. Port the ehaust as big and as smooth as possible with out cutting into the steel sleeve inserts. Use the steel inserts as a template. Use the FD corner seal springs and solid corner seals. They dont cost more than stock, but are better. Unless your side seals are broken you should beable to reuse the side seals. Also if you dont have a rear oil pressure reg that is old and can be taken apart and shimmed, smash the end of the rear oil pressure reg with a hammer and flatten the pointed tip down flatter. That will increase your oil pressure. Dont put a gasket behind the front cover, the gaskets will always leak and allow oil to pass by the oil oring sealing the front cover. Just put a light coat of sealant around the cover. Pre mix.

Snapshot

Have you ever built an engine, bkm rx7? What else?

calvinpaul

iTrader: (2)

I have never rebuilt one, but I have one apart just trying to figure out what I want to/am going to do with it. So by all means, please continue with the conversation.

diabolical1

iTrader: (3)

FIRST ... read the aforementioned threads on www.nopistons.com - read them once , twice and three times even ... make sure you understand.

good oil flow and oil pressure is your friend! (GSL-SE oil pump, RB rear pressure regulator)

clean everything! ... THOROUGHLY! (keep them lubed if they're going to have to sit for any aprrciable length of time)

don't smooth the runners out too much if you're going to keep the Holley intake

bigger Holley carb

i noticed your comment about wanting bigger templates ... dont' get too greedy!

read up on timing and make some colored marks (and a legend) for your main pulley

lighter flywheel

how's that?

calvinpaul

iTrader: (2)

Opps, I've got a question....my dumbass did not mark the timing before I ripped that thing apart. What would I do to put it back togeather right?

bkm_rx7

If you would have read thoroughly..yes...i rebuilt a 13b with my brother...the "what else" pertains to the porting side of things...

mortenf

Dont forget to change all the small and cheap parts when having the motor out, for instance the pilot bearing and throwout bearing. Its a hell of a lot easier to change when you have the gearbox out, rather than forgetting and having to do it all again..

Basically, replace everthing thats cheap and easy!