Redwood

Okay, here's the situation...

I got a free 79 from some guy in my area. Little body damage, frozen engine, and great interior/parts. I ATF'd it and got the engine running great. Problem is there's a seal blown in there and it's burning massive oil (it's actually dripping off the thermal reactor a little bit ). Now, I'm getting an 85 with a good engine/tranny for cheap. I'd like to drop that engine in. Both are 12a's so I don't think it's going to be too hard, but I'm just wondering what I'll encounter. Should I stick with the 79 5-speed (that shifts great BTW) or use the 85 tranny (no info on it yet)? Would it be better to use all the 79 engine accessories like alternator, carb, etc? What kind of wiring will be required? Etc, etc, etc.

Thanks guys.

Sterling

Thinking that this will be a simple "drop right in" fit like it's a pile of Legos is BAD! You'll be in for disappointment concerning the electrical part.

I don't know where your shifter is in the 79, but I'll bet it's in a different place than the 85! The trannys are basically the same...The 85 having supposedly better bearings, but no better synchros.
I would just replace the engine. The pain in yer *** will be hooking up the electric ****. The cluster is different, and the 85 uses a computer that is'nt in the 79.
It'll work, but you'll just have to have a good understanding of wiring.

Get the 85 running tip-top...I mean perfect. That way if there is a problem later, you won't be wondering if the carb just is'nt tuned right, or the ignition is off, ect. Eliminating as many variables as possible in the "Why don't it work?" scenerio is key to getting it running again.

Don't get me wrong - You can do it. It's just that it'll take some doing!

Redwood

Knowing that the wiring is different in both years, what if I did this: Pull out both engines and set them on a table side by side. Take off all the stuff from the 85 engine and set it aside. Then take off all the 79 stuff and bolt it on to the 85. This way, I would retain all the wiring from the 79 assuming that the actual block is the same. Is this feasible? Is it easier?

Keaponlaffen

I've got an '83 engine and an '84 tranny in my '79 GS, and it all lined up perfectly... only problem being that my '79 wiring harness didn't match any of the emissions crap, so I went the easy route and ripped the rat's nest off.. Otherwise everything went well...

I'd say drop the '85 engine in, keep the '79 tranny (if it doesn't whine like mine did), and take the emission crap off.

Jeff

JDuncan

iTrader: (3)

How did you handle the shifter location. FB shifters are a few inches further to the rear of the car than the SA. Did you have to cut the center console of the dash to make it work, or were you able to swap the SA shifter for the remote one on the FB. I have been worrying about this, as my parts car is an 85 and my 2nd gear synchro in the 80 is starting to hate life.

Keaponlaffen

I put the SA shifter and tower on the FB tranny... I didn't have any problems with alignment...maybe the tranny I got wasn't an '84 like the guy I got it from thought it was.. Oh well...

Jeff

85RX7GS

iTrader: (1)

Those cars are very different. I'd suspect that it would be difficult to swap the engines still have everything work right.

Mr Project

Redwood - My '79 is virtually all '85 underneath, the engine and all the suspension is from various '85 GSL's. The electrical issues Sterling is referring to can be side-stepped rather easily if you don't need the emissions equipment. If you needed to swap the '85 emissions equipment over(depends on the law in WA), then things would get complicated, as you'd need the 'ECU', the dash, all the wiring, etc. Personally, I would either ditch all of it and get some headers and custom exhaust, or stick with the '79 emissions system.

The '79 intake requires minor mods to fit on the '85 motor, it supposedly flows better than the '85 manifold, but the '85 will fit without mods (duh, since that's what it came on). Your call on what to do there... you can bolt your non-computer-needing '79 carb to either manifold.

The part I'm not sure about is keeping the '79 exhaust with the thermal reactor if you need the '79 emissions equipment. I *think* if you do the mods(it just needs a block-off plate to cover the extra exhaust port on the later motor) and mount the '79 intake, you could use the original '79 exhaust, thermal reactor and all. Not totally sure though, and if you go headers/full exhaust, you won't have to worry about it, plus you'll gain 15-20 HP for your trouble.

Either way, definately keep the '79 tranny, as according to Felix Miata's page, the '79 trannys can't just 'swap' the shifter/tailhousing stuff over to the '85. According to Felix's page, Keaponlaffen must have had a late '80 tranny that has that ability. If your '79 tranny is good, go with it, it'll bolt to the engine just fine.

Hope that helps! I like the SA-22C's for the unique style, the light weight, and the fact that mine was basically free. You CAN have the best of both worlds!

Armen

jeremy

iTrader: (1)

ditch the thermal reactor. they're heavy and restrictive. bolt headers up while your doing the swap.

Redwood

Great! Here's my plan then. I'm going to drop in the 85 engine and ditch all the emissions stuff. I'll use the 79 tranny too as that could only complicate the swap. What headers should I be getting then? The ones for the 79 or the 85? I was under the impression that headers are determined first by the body rather than the year. Thanks for all the help guys.

Keaponlaffen

you need headers for the '85, the '79 has two extra little ports that you don't need, and I'm assuming they'll leak if you slap a '79 header on there...

Jeff

KenA

Actually my 79 Header from RB didn't have any extra ports...It just blocks the two small ports from the motor off...