I finally got my 86 na started, but it won't start without putting atf in the vacuum line at the front of the plenum. It's street ported(i went pretty big)then I matched and ported the runners and intakes, removed all the emissions junk, built a custom header , 21/2' exhaust and cold air intake. I know this idle things bit covered before, I'm new to the club thing and having a hard time finding some of the info. Could it be the bac? It's as if the cold starts not working at all.
Any help would be much appreciated. Almost forgot, I cleaned up the bathtubs on the rotors(ground and polished them) how much could that reduce my compression if at all?

 

A new rebuild is going to be hard to start for awhile. There's not much you can do about it.

 

how many miles on the rebuild and what did you reuse.

 

I was able to reuse all the apex seals and all but a few of the side seals(i dropped a couple and they broke. The motor only had about 80k on it and it was mildly ported already. Didn't know til I tore it down. That would explain beating all those stock na's. And I just thought I was a good driver. LOL.
Also it seems as though the fast idles not working. Is that normal on a fresh or somewhat fresh motor?

 

Well, it looks like its already getting a lot easier to start. I took it around the block today and its running great! I'm stoked! Little too loud though with the straight through mufflers. Thinkin about making inserts for the tip to quiet it down a bit.

 

why'd you reuse the apex seals?? i would have replaced them for the simple fact that the engine was open.

 

Reusing apex seals isn't a smart idea, even if they look to be in still useable condition, it is just one of the things you replace when opening up a stock original motor. If a motor has already been rebuilt and there is only a few thousand miles on it and it is reopened for some reason, I can see reusing them, but not original apex seals.

 

I reused them because they had lots of material left on them and the housings have some flaking around the edges. The old ones are already worn to sut the housings. If I could afford new housings it would be a different story. Besides this was my first port job and if **** was to go wrong I wanted to keep the cost down. Not to mention they weren't the orig. the motor was rebuilt at 140k by Can Jam.(Rotary guru for our area. )

 

Agreed with brent, for the simple fact that the housings and seals are matched... Also keep in mind that even mazda will reuse apex seals in their reman's if they are within spec. Personally though, i would replace them just for the fact it was opened up..

-Justin

 

Oh and to add to the starting problem... Just give it some time, and let it run... Drive it smoothly, don't take it above 4KRPMS.. During my breakin, i didn't take it over 4k, changed oil at 500 Miles, then 1000 miles... (Also i was using new housings) After about 1500 miles is when i started to really step into it...

A good breakin will determine the longevity and the strength of your motor. Remember when using used housings, compression will be a bit low in the beginning, just give it time..

Congrats on your successfull rebuild!

Justin

 

Thanks for the tips. It's running great now and starts on its own. I haven't driven much though cause I went around the block a couple times and it was makin really good power but then I blew a brake line.LOL So now I'm doing the brake and fuel lines and the fuel filter. Already knew they needed to be done anyway.

 

Wow im really suprised mazda reuses apex seals, thats good to know. And with the apex seals, i had my motor all torn down and all the work i did cleaning and taking it apart i would have felt sick putting in old apex seals...so i bit the bullet and bought a set of Rotary Aviation seals for 180 bucks or so. Just some peace of mind

just remember though, you're lucky you can get your car started at all, i wish mine was just hard to start, hell any kind of starting would please me right now.

 

what are you asking for the fb? I might be looking for one in the spring. (I know that's a while from now but you never know) I need to sell my 87 first so I can finish the 86. You probably already know but the ATF in the vacuum line worked really good getting mine started. Hope you get it running soon. I know what its like.

 

i have a question! What apex seals are good for High compresion..Like over 110psi.. or 10-1. i think my stock rotors are 9.4-1.. and turbo's are 8.4-1 but is it a good thing to get more compression?

 

check the archives, you'll find a lot of guys (even in race engines) prefer the stock seals. Also upgrading to 3mm seals from what I read really isn't worthwhile.

 

As far as seals go, i've used RotorSports Racing seals (as far as i know, Re-Badged RA seals).. I have a buddy running Rotary Aviation seals as well, and no problems at all. They seem to seal pretty well, although proven research has shown that they require a bit longer of a break-in cycle to reach maximum compression.

Now talking about higher compression, the only ways you will be able to change your compression ratio is if you change do a different year rotor.. (Series 5 rotors, Renesis Rotors)

If you are going for a higher compression, i'd stick with the S5 rotors, but with a ported s4 or s5 motor, you can still acheive a good amount of power..

-Justin