RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   1st Generation Specific (1979-1985) (https://www.rx7club.com/1st-generation-specific-1979-1985-18/)
-   -   Brainfarting around... (https://www.rx7club.com/1st-generation-specific-1979-1985-18/brainfarting-around-1011501/)

foghead 09-12-12 08:29 PM

Brainfarting around...
 
The car - a mint condition 1983 GSL with a newer limited slip rear from an 84, all new bushings and a 12a that was rebuilt with about 55k on it (157k on the body). Zero bondo and 100% straight body-wise. Not certain if it was done up with new rotor housings or not when it was done, but either way, it runs perfect.

http://img191.imageshack.us/img191/5026/img0146vy.jpg

http://img28.imageshack.us/img28/2847/img0154xx.jpg

My options -

1 - leave it the hell alone and 100% stock
2 - keep the 12a, throw a racing beat exh on it, maybe ditch the rats nest and basically do a light mod to the car and switch to pre-mix
3 - sell the 12a as an excellent runner and grab a 13b to swap into the car to get a little more to play with or...
4 - pure sacrilege - lose the rotary and go with a 4.3 or SBC and be done with it totally. Hell, I can get everything I need from a donor car for the price of the 12a RB exhaust!!

My main hesitation regarding any mods is that the car is genuinely THAT nice. Runs/starts/drives 100%... but I kinda would like to make it 100% without worrying about some oddball emissions failure or the death of the 12a.

I'm kinda leaning towards a cross between #3 and #4 just due to the financial aspect of building a 13b... but everything is on the table here. As a side note, I REALLY like the way the rotary delivers the power!! Insanely smooth and deceptively fast!! A 13b would be my choice if $$$$'s weren't such a concern. Financially right now, #1 is where it stays due to being broke!

Chime in and let me know what the thoughts are!!!

85rotarypower 09-12-12 10:26 PM

The decision is ultimately yours to make but my choice would probably be #3 with a twist. Stock S4 13bt with a free flowing exhaust and standard 2nd gen mods for a small power increase. 220hp at the flywheel is not hard to obtain out of that engine and it wont likely grenade your drivetrain like a V8 swap would. Keeping the engine close to stock will also net you excellent drivability with a smooth power delivery similar to stock 12a.

Im not totally against piston swaps but when it comes to reliability of the stock rear axle a v8 is not what you want to do. Much more than 250 ft lbs torque i think the rear axle will snap like a twig with grippy tires. The small bearing early 1st gen axle is even less than that.

82FanTC 09-12-12 10:37 PM

Wow that looks pretty nice! I would do one of two things. Remove emissions equipment, add a racing beat exhaust, and mod your stock carb and be done.

Or sell it as is and buy one that already has a 13b/bt swapped in. You will save big bucks in the end

Sgt.Stinkfist 09-12-12 10:47 PM

hmmm, I say Cosmo S5 13B, NA, street port AND semi-P port

DreamInRotary 09-12-12 11:09 PM

I'm considering similar options for my car as well. I'm leaning towards keeping my 12a, heavy bridge porting it, block off emissions and OMP and go to premix, and DLDFIS (I think that's the correct acronym..) as well.

j9fd3s 09-13-12 12:28 AM

#1, maybe i'd put headers on it

foghead 09-13-12 07:37 AM


Originally Posted by 82FanTC (Post 11220100)
Wow that looks pretty nice! I would do one of two things. Remove emissions equipment, add a racing beat exhaust, and mod your stock carb and be done.

Or sell it as is and buy one that already has a 13b/bt swapped in. You will save big bucks in the end

Thanks! I have to allow for at least an extra 20 minutes everytime I take it out as I almost always get locked into a conversation about the car by someone that starts off with, "I haven't seen one this nice in AGES!" Buffalo weather/winters killed a lot of these off...

I'm looking at #2 as the most likely scenario for now, and that's only because the thing runs so well that I'm thinking (knocks on wood here) that it's easily a 100k mile motor. Atkins did the build and the previous owner was pretty good about changing the oil... all in all, it's a VERY strong car as it is.

foghead 09-13-12 07:40 AM


Originally Posted by 85rotarypower (Post 11220089)
The decision is ultimately yours to make but my choice would probably be #3 with a twist. Stock S4 13bt with a free flowing exhaust and standard 2nd gen mods for a small power increase. 220hp at the flywheel is not hard to obtain out of that engine and it wont likely grenade your drivetrain like a V8 swap would. Keeping the engine close to stock will also net you excellent drivability with a smooth power delivery similar to stock 12a.

Im not totally against piston swaps but when it comes to reliability of the stock rear axle a v8 is not what you want to do. Much more than 250 ft lbs torque i think the rear axle will snap like a twig with grippy tires. The small bearing early 1st gen axle is even less than that.

A 4.3 would be too torquey? Wasn't there a heavier fist gen axle from the later years? The axle in this has disks, a lsd and was either out of an 84 or an 85...

t_g_farrell 09-13-12 07:44 AM

I'd replace the beehive with a FMOC first.

Enjoy the stock everythng until it becomes a pain in the butt to maintain.

Then get the RB SP Full Exhaust setup. Then replace the nikki with a nice big Dell or Weber
DCOE. Do eletric fans and a better ignition setup and enjoy a 12a with 50% more
power without breaking the keg.

Save up for a new 13B engine for a few decades when the 12A finally blows.

foghead 09-13-12 10:08 AM


Originally Posted by t_g_farrell (Post 11220327)
I'd replace the beehive with a FMOC first.

I've used the search feature on here many times to see if I could find a how-to for replacing that beehive. Can you possibly help me here with a link that has complete instructions? Right now, I don't have any access to a used 2nd gen oil cooler either. I kinda wanted to get that replaced as well as get some electric fans on it in the immediate future... link for fans too possibly? :nod:

foghead 09-13-12 10:11 AM

Also for anyone that might be able to shed some light on this idea, I have an intake mani from a 79 or 80 that doesn't have the shutter valve on it. Is it a better manifold than the 83 unit? Would it be a wise thing to replace it possibly? I also have the Nikki from that mani, but it's in pretty rough shape... now I'm up to 3 extra carbs... :D

Jeff20B 09-13-12 10:45 AM

Search "ACV port" and "quicksteel"

KansasCityREPU 09-13-12 11:14 AM

replacing the beehive is a good idea. I'm in the process of going to a FMOC in my 1985 GSL and here are my thoughts.

If you have the money ($500) you can go the route I did. I would not recommend going completely aftermarket unless it something you really want.

Here is a thread with my setup: https://www.rx7club.com/1st-generati...ooler-1011061/

* Rotary-Works 10 row -10an FMOC
* Steal braided hoses
* Custom fabbed mounting braket
* Earl's oil temperature regulator
* RE-Speed oil pedistal
* Oil temp and oil presure gauges
* Endlink bushing kit to isolate vibration

My suggestion would be to get an GSL-SE oil cooler or even a 2nd gen cooler and have a hydrolic shop make up some hoses with the factory fittings. You will also need either a non beehive oil pedistal or get the Re-Speed one.

mazdaverx713b 09-13-12 12:15 PM

i would not touch a thing personally. unmolested 7's are getting harder and harder to find and when completely stock, they get decent mileage, are reliable, and are very enjoyable to drive. i find that more issues will arise in the future with modded cars.. not saying a recing beat exhaust and removing the emission equipment will necessarily harm anything, its that you may end up missing the bone stock classic.

foghead 09-15-12 06:35 AM


Originally Posted by mazdaverx713b (Post 11220594)
i would not touch a thing personally. unmolested 7's are getting harder and harder to find and when completely stock, they get decent mileage, are reliable, and are very enjoyable to drive. i find that more issues will arise in the future with modded cars.. not saying a recing beat exhaust and removing the emission equipment will necessarily harm anything, its that you may end up missing the bone stock classic.

Looks like the oil cooler mod will be it for now... That and maybe a racing beat exhaust, minus the header. Anything to help get the heat out of the motor and give it a running chance at a longer lifespan....

85rotarypower 09-15-12 10:45 AM


Originally Posted by foghead (Post 11220325)
A 4.3 would be too torquey? Wasn't there a heavier fist gen axle from the later years? The axle in this has disks, a lsd and was either out of an 84 or an 85...

Im not saying the 4.3 is too torquey. The v8's generally are. The later 1st gen axles are stronger but can still be broken with about 250ft lbs. That seems to be about the limit if you want to run slightly sticky tires from what i have read.

84stock 09-15-12 11:15 AM

I would go with the bonez cat repalcement pipe. It's only $75, heavy duty, sounds great and a lot cheaper than a whole new exhaust.

Worked great on my low mileage 83.

Rotary Performance | SA Exhaust

KansasCityREPU 09-15-12 02:15 PM


Originally Posted by 84stock (Post 11222885)
I would go with the bonez cat repalcement pipe. It's only $75, heavy duty, sounds great and a lot cheaper than a whole new exhaust.

Worked great on my low mileage 83.

Rotary Performance | SA Exhaust

If you go this route, do you have to delete the air pump?

tasty danish 09-16-12 07:00 AM

I wouldn't touch a damn thing till it broke.

Though I do PASSIONATELY hate the stock header (if you can even call it that) and would do a full exhaust with header, and maybe a FMOC because hives are just crap.

But with the shape it's in, you may consider plastic wrapping anything you do take off...

foghead 09-16-12 11:38 AM


Originally Posted by 84stock (Post 11222885)
I would go with the bonez cat repalcement pipe. It's only $75, heavy duty, sounds great and a lot cheaper than a whole new exhaust.

Worked great on my low mileage 83.

Rotary Performance | SA Exhaust

DUDE! That is EXACTLY what I was trying to find!! Thank you!!! This and the RB muffler will probably tie it up for me!

Plus, the cash I get back from selling the convertor will offset it's cost. I love it when a plan comes together!! :git:

foghead 09-16-12 11:40 AM


Originally Posted by tasty danish (Post 11223743)
I wouldn't touch a damn thing till it broke.

Though I do PASSIONATELY hate the stock header (if you can even call it that) and would do a full exhaust with header, and maybe a FMOC because hives are just crap.

But with the shape it's in, you may consider plastic wrapping anything you do take off...

Yeah... the cat delete pipe is a certainty, and the oil cooler will also be tagged and bagged over this winter. This car is nice enough to try and preserve.

tasty danish 09-17-12 03:49 AM


Originally Posted by foghead (Post 11223903)
Yeah... the cat delete pipe is a certainty, and the oil cooler will also be tagged and bagged over this winter. This car is nice enough to try and preserve.

The stock exhaust header is a boat anchor and flows exhaust through it about as well as a boat anchor would... just saying :egrin:

foghead 09-17-12 01:08 PM


Originally Posted by tasty danish (Post 11224738)
The stock exhaust header is a boat anchor and flows exhaust through it about as well as a boat anchor would... just saying :egrin:

Understood for certain. It'll disappear eventually, but for now though, it comes down to 80 or so for the delete pipe or 800 or so for the full system. Besides, preservation is the name of my game. The header will/would be nice, but worrying about extra hp from the 12a just isn't in the best interests of the motor, seeing as how parts have dried up pretty badly. It'd likely help hot gasses to escape faster than the iron blob but once again, just not in the budget at the moment.

DivinDriver 09-17-12 02:45 PM

Beautiful restoration candidate; you can either restore it to original condition (mainly some replating and cleaning from what can be seen) and preserve it's value, or you can start modding it to your taste with the realization that every dollar you spend on non-stock mods will be reducing the value of the car by several dollars.

Just a sad fact; with very rare exception, nobody wants somebody else's mods. So figure out what you'll enjoy most before you start.

foghead 09-18-12 07:56 AM


Originally Posted by DivinDriver (Post 11225220)
Beautiful restoration candidate; you can either restore it to original condition (mainly some replating and cleaning from what can be seen) and preserve it's value, or you can start modding it to your taste with the realization that every dollar you spend on non-stock mods will be reducing the value of the car by several dollars.

Just a sad fact; with very rare exception, nobody wants somebody else's mods. So figure out what you'll enjoy most before you start.

Also a good point. As it stands right now, I'm going with the cat delete pipe and RB muffler. Will be removing the air pump (and storing it) and going to a double pulley on the alternator. Already also have the OMP adapter that allows for a separate tank of 2 cycle oil to be fed into the motor.

Those mods will likely be about it. All suspension bushings are new urethane, springs are all new, struts/shocks too. Nothing else is on the radar at this point in time. I'm going towards restored/preserved with tasteful and logical mods done. :icon_tup:

DivinDriver 09-18-12 09:26 AM

Reversible mods are always a good plan. Sounds like you've got a clear picture of what you want to do.

Enjoy!

RGHTBrainDesign 09-23-12 04:29 AM

Subscribed. I'm in about the same boat. Good luck with everything.

foghead 09-23-12 05:38 PM


Originally Posted by SirLaughsALot (Post 11231690)
Subscribed. I'm in about the same boat. Good luck with everything.

TY... latest project - a new drive shaft/prop shaft. Ouch. The car has been leaking transmission oil out of the rear seal since I acquired it about a month and a half ago, so now that the pervertor (convertor) is gone, I was able to drop the heat shield and see what was going on under there... both u-joints are wanged to varying degrees, so here comes a new shaft from Cali with replaceable joints.

Still staying stock-ish for now mainly due to funding limitations

KansasCityREPU 09-23-12 08:12 PM


Originally Posted by foghead (Post 11232260)
TY... latest project - a new drive shaft/prop shaft. Ouch. The car has been leaking transmission oil out of the rear seal since I acquired it about a month and a half ago, so now that the pervertor (convertor) is gone, I was able to drop the heat shield and see what was going on under there... both u-joints are wanged to varying degrees, so here comes a new shaft from Cali with replaceable joints.

Still staying stock-ish for now mainly due to funding limitations

The u-joints in the factory driveshaft can be replaced. I took my driveshaft to a driveshart shop and the old stacked u-joints were replaced with servicabled ones. Cost me $100. I went ahead and powdercoated the driveshaft after the old u-joints were removed and before the new ones were installed.

http://i1133.photobucket.com/albums/...ps92876533.jpg

foghead 09-24-12 03:47 PM


Originally Posted by KansasCityREPU (Post 11232376)
The u-joints in the factory driveshaft can be replaced. I took my driveshaft to a driveshart shop and the old stacked u-joints were replaced with servicabled ones. Cost me $100. I went ahead and powdercoated the driveshaft after the old u-joints were removed and before the new ones were installed.

Looks nice! The only place in town said, 'not possible - must replace both yokes 'n weld new ones onto the shaft itself'. The end that goes into the trans also had a serious notch worn in it where the trans seal rides, causing the fairly massive oil bath under the car. I gotta take a pic of this thing... it's truly awful under there. I've only had it for about a month and change and I'm honestly quite amazed that it didn't cause a grease fire in the tunnel. No joke! Previous owner is a nice guy but a mechanic, he's not as I consider this whole repair not much more than basic maintenance. Also noticed that the trans mount has a bit of a rip in it. Good thing I anticipated that and purchased one when I first got the car.... :D

RGHTBrainDesign 01-11-13 10:06 AM

Ugh, I need to start a build thread instead of just posting all my work on Facebook, hahaha. Today I'll shoot another couple videos for everyone and post it up to my YouTube channel.

I don't mean this as a thread steal, but we are in very similar situations.

rx7lives 01-11-13 12:25 PM

Your right about that
 

Originally Posted by 85rotarypower (Post 11220089)
The decision is ultimately yours to make but my choice would probably be #3 with a twist. Stock S4 13bt with a free flowing exhaust and standard 2nd gen mods for a small power increase. 220hp at the flywheel is not hard to obtain out of that engine and it wont likely grenade your drivetrain like a V8 swap would. Keeping the engine close to stock will also net you excellent drivability with a smooth power delivery similar to stock 12a.

Im not totally against piston swaps but when it comes to reliability of the stock rear axle a v8 is not what you want to do. Much more than 250 ft lbs torque i think the rear axle will snap like a twig with grippy tires. The small bearing early 1st gen axle is even less than that.

Your right about that. I've gone through three rear ends and one pumpkin since '92 on a virtually stock SE. Now I drive conservatively.

Regarding Foghead's new car, I would keep it stock with maybe some light mods. It's beautiful and a v8 will destroy your rear end the first time you get on it hard.

foghead 01-12-13 05:42 PM

Yes... the 12a is going to stay pretty much where it is until something breaks. Currently, the mods are:

- cat delete with resonator pipe where it once resided (massive improvement in the way the car runs!)
- air pump delete with dual alternator pulley
- rotary aviation oil injector pump adapter with a separate 2-cycle engine oil tank (kinda funny now - when it starts it smells a lot like an Evinrude outboard... :lol: )
- rb muffler (to be installed sometime in the near future)
- all suspension bushings have been replaced by urethane stuff
- glass sunroof panel (pretty sweet, says I.... :nod: )


Additional future mods:

- possibly finding another parts car to pirate some interior parts from...
- a set of konig rims so I can jam some 15" tires on the car. They just don't make any 13" tires that are worth a damn...
- a set of new springs if I can find any... all I can find are lowering springs and it may come to that...
- and new struts/shocks to finish it off

That's pretty much where it'll stop and be enjoyed... all mods thus far are pretty much reasonable and should do nothing but add value to the car...

I've got a few months of winter to mess with it all... I'll tell you what though - the amount of people stopping to talk to me about the car was really incredible while it was on the road... my now sold Neon SRT-4 never got that much positive attention!!!

(PS - if by some chance I run into ca$h, I may - just maybe - consider sending the 12a out for a mild street port... but that's waaayyyyyyyyyyyy at the end of a long list of other priorities for now!)

HAUNTED HAMMZ 01-12-13 09:54 PM

#2 nothing to wild and off the wall. Remember CLEAN AND SIMPLE NEVER GETS OLD.


All times are GMT -5. The time now is 02:54 PM.


© 2024 MH Sub I, LLC dba Internet Brands