RustyRacer

It finally went, after being neglected for 11 years, then coming into my posession for 5 and being driven over 12,000 miles. I enjoyed the hell out of this motor.


If it starts to sound like a VW Beetle then a seal is probably about to go.

Things I'm considering:
Im thinking that housing is shot like most of the ones i've seen.

Blocking off the rear side of the carb and running it around town.
Finding another 12a in better shape.
302 swap, no pinche chevies
Or full car swap.

Anything else i could do?

rotornoob

iTrader: (2)

Swap in a 13b? Its injected, housings are readily available, and the engine has more torque and hp... Just my .02

Jeff20B

iTrader: (13)

Look for an old school 13B. It's carbed, your Nikki can be reused, more torque and HP.

rwatson5651

iTrader: (5)

+1 , Old school 13B is the way to go.

aa35199

iTrader: (1)

Blocking off the rear side of the carb and running it around town.
-A ticking bomb that WONT thrill and entertain you when it goes off at worst possible moment.

Finding another 12a in better shape.
-The cheapest and easiest option, I did the same on my first fb for under $800 (thanks japan2la!)

"302 swap, no pinche chevies"
I love my 5.0 FB, it's shockingly fast, and now I'm no longer being bullied around by the Jimmy Johns driver in his stupid accord at red lights. It will cost you a lot more money and time then you think BE WARNED!

My logic was, do I spend too much money on a strung out bridge ported or turbo rotary, or do I spend the same amount and get a little more power then the rotary option by swapping it out for the 5.0. I'll lay out the pros and cons I observed.

Pros
-I'm still getting used to the fact autozone has every thing I need and want in stock.
-The argument that it ruins the handling in my experience is not true
-I average 21mpg mixed (carb, and I step on it frequently)
-I have ample power at any rpm
-has a lot of "cool factor" to non rotary car enthusiasts, otherwise known as the 99%.
-craigslist is your buddy!
-The engine itself is still stock, and the sky is the limit in terms of power, awesome DSM like hp/dollar ratio
-reliability is dictated solely by how many short cuts you took during the build.
-roughly same power as a mildly tuned TII engine when stock
-more power then a heavily tuned TII engine if you decide to go with a top end kit, and that's before forced induction.
-This was my first build, my first swap, I learned a lot very quickly.

Before the cons please keep in mind I wasn't that experienced before I started so things were more difficult as a result. I also set a standard that when completed the car must look, run, and feel as if it came with the motor from the factory so I spent a good deal of time making sure I retained stock appearance and functionality of every thing inside and out (still working on improving the appearance and ground clearance of the exhaust).

Cons
-You will think you only have to buy the motor, trans and swap kit when you are figuring the cost, WRONG! My swap nickled and dimed the hell out of me, swaps in general hen peck you with $30 here and $50 there. You will rack up 1-2 grand in the "misc" column.
-You will face issues and problems you never thought you would have to deal with, and the 6 printer sheets of instructions grannies speed shop sends with the kit wont get you too far.
-Once you bolt the engine in the easy and fun part is over, you will now spend all you free time over the next few months with a test light and constant pessimism as to whether or not you will finish rearranging every thing in the electrical and fuel systems to work with your ghetto rigged monstrosity. Oh and btw 1 screw up during this stage can turn into a frustrating electrical gremlin down the road, or turn your FB into a car bomb.
-Exhaust=fffffffffffffuuuuuuuuuuuuu!!!!!!!!!!!
-stock mazda 3.909 rear diff gears are great for acceleration, but makes 1st gear useless, and makes freeway mpg worse then city/country
-Once your done you realize how beastly your car would've been had you bought a mustang in the first place.

I was not that experienced before tackling this project, I learned a hell of a lot through trial and error, it reminded me a lot of mega man for NES, you would get a little further in a stage, then die, come back and get even more further, then die again, repeat, until you have beaten the stage. The same controller flailing frustration was with me through the whole build, in fact I even got a decal for my quarter window as a tribute to this similarity to my childhood.

Over all worth it, so worth it! and that is my god honest opinion on the swap.

"Or full car swap."

RustyRacer

The old school 13B would be great, even crossed my mind with a Renesis.

I already sourced a 302 and T-5 from friends. Hydraulic roller that needs a complete rebuild, and the T-5 is blown out. Tempting to just buy a running mustang thats been wrecked and throw that in. I've got time and money to think about it now, theres also the paintwork, and full bushings to do.

Jeff20B

iTrader: (13)

I just put an old school 13B in mine yesterday. Sitting on the hocky puck motor mounts for now. More work'll get done when the weather stops raining.

See this is my fun bolt on one. full RB exhaust, carb, new RB SS front mount bar etc. The other has a 20B and it's kinda like a V8 swap because everything needs to be redone in the engine bay. It's the one that makes me hate life right now. But I gotta keep at it because it'll be worth it in the end. Of course being the steward of 10 cars right now can be tedious for anyone. Only leaves me with 10% for the 20B which isn't enough - gotta finish some others first. Talk about nickle and dime. But I took this on. If I don't finish, I'll hate myself.

aa35199

iTrader: (1)

having and keeping a donor car during the build will save you from a lot of the bull **** I had to endure.

Glad to hear your still working on the 20fb, I subscribed to your build thread a while back, I still check it once in a while.

85rotarypower

I can't really comment on the piston engine swaps like the 302, but IMO, your just asking for trouble if you don't go all the way with a complete axle swap as well to a Ford 8.8 or similar axle. Even under stock late 80's to early 90's Mustang power levels, I don't think the stock FB rear axle will last long if you try to use the power all that much, not due to HP, but because of the torque of the V8. So this will just add to your list of things to do and push up the cost of the swap even more. There are other things as well, such as the brakes and wheels/tires, both of which in stock for really have no place on a V8 swapped FB IMO. The stock brakes can be considered barely adequate with the stock engine.

I have done the 2nd gen NA engine swap retaining the fuel injection on one engine I had in my 82. Aside from keeping the stock 12A, this is probably the best bang for your buck swap you can do and will net you a decent 150-160 hp with a RB header and free flowing exahust. In a car as light as the FB, this will feel pretty quick. The power level won't grenade your stock rear end and the engine is also quite happy with the stock FB gearing and transmission, which will bolt up without any issues. If you look around, you can probably find a real good engine with everything still attached for $1000, and add a little more for some electrical wiring and various other bits for the swap, for about $1300 or so this swap could be done very professionally, probably the cost to rebuild your 12A at this point.

I think this is a great option for anyone wanting a mild power increase that will not break the bank and allows you to retain more of the original parts. It is ultimately your choice to swap in whatever engine you want, but if you don't do it right at the start, you are just asking for trouble down the road.

rrob311

There are a lot of 13b engines available JDM.

aa35199

iTrader: (1)

+1
I do okay, but when you do a drastic motor swap it is incredible the amount of work and cash you put in to keep a balanced car, keep in mind I'm running stock heads and cam so now power wise I'm only making what a TII would make with a modest big turbo setup. No diff problems but I NEVER launch (open diff anyways) also the GSL rear can take quite a bit of power so long as you don't hook up with a pair of drag slicks paired to an overkill motor. Overall the rest of the car is well matched for the engine's weight and power. BUT if I decide to get a top end kit, or build the motor, my car all of a sudden will have 350-450hp under the hood, but it still would have coffee can lids for brake rotors. The most dangerous thing is just being disoriented to the cars new rate of acceleration. Your car may feel confident now, but when 150 mph becomes not only possible but very easily accessible, you can find your self in hot water fast. I remember how my 12a would struggle to get past 110mph over several miles of freeway, now 110mph is easily achieved before the end of the on ramp.

RotaryEvolution

iTrader: (30)

old school 13Bs aren't any easier to find than a good condition 12A, the nikki may be used but the hitachi carb was jetted for the larger displacement so the smaller nikki jets won't give the same original power and may cook the seals running it lean.

better off doing a late model 13B swap with the better chrome housings which lasted longer, better fuel economy and torque. the early 13B is a much easier swap though IF you can find one and it is in decent shape still(but get the hitachi carb to go with it).

otherwise a V8 swap isn't such a bad idea, but go simple with a carb setup, no need for a $5k newer injected motor swap when you can find a complete engine for about $1k and have less hassle with the fuel pump, wiring issues, fitment and everything else that goes with shoehorning a newer V8 in there. only reason to use a newer injected V8 is for the fuel economy, the torque even with a carbed V8 will be plenty and likely even still too much for most purposes.