roadjob

I have finally made enough money to put my 85 12a back together. It has not run in over a year and a half now and I have decided I will do some kind of port, whether it be street or mild bridge. Anyway, I am rebuilding the carb and planning on purchasing Atkin's master rebuild kit. I want to get it running with as little fuss as possible, so I would like to rebuild it stock, set it up to run like it supposed to and then take it back apart and port it. My question is if I rebuild the motor and run it for ~1000 miles and port it, will I be able to reuse all the seals or will I have to buy new seals (like the water jacket seals). Sorry for the long message and thanks for the help.

ACR_RX-7

iTrader: (1)

You can reuse all of the hard seals. The soft seals are usually up for debate, but I believe that the Atkins viton seals are reusable as long as they are in good condition. As long as all of the seals go back exactly where they came from, you should be ok. The gaskets on the other hand, intake, WP, exhaust, etc. don't like to be reused. They tend to split and break.

The front crank seal and rear main should be ok provided you keep them clean.

If you are going through all of the effort to do the job in the first place, just port it while it's apart. Do a mild street port, not a bridge, and be done with it. If you get it running stock and get it all dialed in, once you port it you will have to start all over.

Get a solid plan together first. Pull the engine apart carefully and label everything and inspect every piece as it comes apart to deem it good for reuse or not. The master kit may be a bit overkill and you may have leftover parts.

Read this thread.

https://www.rx7club.com/2nd-gen-arch...ok-how-639375/


and this thread


https://www.rx7club.com/2nd-gen-arch...ebuild-946068/



Watch these videos:







Also, read through this:
https://www.rx7club.com/1st-generati...q-page-237777/


This:

https://www.rx7club.com/1st-gen-arch...thread-217446/



And maybe this:

Porting

And this:

https://www.rx7club.com/new-member-r...rimer-1039179/



Finally, good luck.

roadjob

Thanks for the help. I'll take a look at those threads tonight. I was only thinking it may be better to separate the two because of rebuilding the motor and carb and trying to limit the variables.

ACR_RX-7

iTrader: (1)

Nope. Do it once and do it right. That way you can match the induction system to your port. A stock Nikki carb will not support a bridgeport effectively and the jetting is all wrong. A street port can be done, but you still need to tune and jet the carb. Paul Yaw used to build stock Nikki carbs for all kinds of applications, but his site has long since been down. I'm sure there are other 12A guys that can point you in the right direction.

Look at a holley 4 barrel setup if you want to maximize your airflow and power. Do not buy an off the shelf, or a used one. Get a Holley 4 barrel kit from Racing Beat or a rotary specialist in general. Now if you find a used one that came off a rotary application with manifold, that should be fine.

You can also get a Weber IDA setup that would work well too, but it's all about budget and what you want to accomplish. Since you are asking about reusing soft seals, I'm going to be rude and assume you don't have a ton of cash.

A soft seals kit is about $160 from Atkins, so I would just buy new if I were to split the engine down again.

What I don't want to see happen is you spend all the time, money, and effort to build it 100% stock, get it running. Then tear it down to port it. Do the incorrect ports for your induction system and then throw it together as stock and try and get it to run and operate. That process is maddening and will not produce decent results.

You would spend so much more time trying to fight with stock components, than if you just went for a matched package assembly.


Here are a couple more links:

Mazspeed's First Generation Rx-7 Club Page

https://www.rx7club.com/1st-generati...inions-703097/

Naturally Aspirated Performance Forum - RX7Club.com

https://www.rx7club.com/1st-generati...8-ida-1100983/

ACR_RX-7

iTrader: (1)

oops

roadjob

I am in college so money is certainly limited haha. Yeah, I was planning on getting a Holley from racing beat along with a header. I will do all new exhaust with the port/new carb. I assume I will also have to upgrade the fuel delivery system as well?

Right now I have only looked at the master kit on Atkins, for 160 I'd probably buy new soft seals. So far, everyone has been very helpful and suggested that I do all work at once, which is probably what I'll do.

ACR_RX-7

iTrader: (1)

The racing beat header for the 12a is very well designed. Get the street header with the single output and get the presilencer as well. It all bolts up to the stock rear section. You can then get a new rear muffler and have a nice sounding 12a. Don't buy a pacesetter or any other trash out there. IMO, there is not a better header than the Racing Beat unit.

The fuel delivery would just require a pump and regulator. If you go Holley from racing beat, get a holley pump and reg to keep things simple.

Aaron Cake

iTrader: (1)

Don't bridgeport the car unless it is a track only vehicle.

If you bridgeport, you will need to upgrade the carb and manifold, as well as have a very free flowing exhaust. It will be LOUD. It will get 8 MPG in the city. And in order to take advantage of all that high RPM power the bridgeport freed up you really should build the engine for high RPM use.

ACR_RX-7

iTrader: (1)

And by build for high RPM, you would probably need hardened stat gears, clearanced rotors, balanced rotating assembly, oil modifications, and then drive the car above 4000 rpms just to take advantage of the port. But oh good night would it sound cool.


Or, mild street port and enjoy the hell out of it. That's what I would do.