1985 engine swap?
10-20-13, 02:21 PM
#1
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1985 engine swap?
Unlike most engine swap threads, I am not looking for a performance engine to throw into the car. Just last week I bought a 1985 rx7. I have no idea what type it is because the only paper work it has is the title......and that is about it.
I personally have not started the car (still looking for a good deal on a battery), but the original owner says that when she starts it up, black smoke and some water comes out the back.
Now she probably just flooded the engine, so no big deal. But according to her, the original engine is still in the car......and it has close to 300,000 miles on it. Sooooo the engine is going to die sometime in the near future.
That all being said, I am a college student, who can't exactly afford a whole lot. I have searched around google for a engine to swap into the car, but all I can find are people talking about throwing a rather expensive performance engine into the car. In comparison, I would be happy with a toyota engine that doesn't chew up a lot of gas.
However, I have no earthly idea what kind of engines can fit in my car without major modifications.
Any ideas?
I personally have not started the car (still looking for a good deal on a battery), but the original owner says that when she starts it up, black smoke and some water comes out the back.
Now she probably just flooded the engine, so no big deal. But according to her, the original engine is still in the car......and it has close to 300,000 miles on it. Sooooo the engine is going to die sometime in the near future.
That all being said, I am a college student, who can't exactly afford a whole lot. I have searched around google for a engine to swap into the car, but all I can find are people talking about throwing a rather expensive performance engine into the car. In comparison, I would be happy with a toyota engine that doesn't chew up a lot of gas.
However, I have no earthly idea what kind of engines can fit in my car without major modifications.
Any ideas?
10-20-13, 04:33 PM
#3
I have a couple of questions. Since your a college student, you're a smart guy. I can understand not having much money. How much research did you do before the purchase? Do you know how much a rebuilt engine is going to cost? If it where me in your situation, try and find a cheap used 12A. The aren't very easy to find. The last 12A engine I had rebuilt cost me $1500 and I supplied all the parts ($5000 total). I'm guessing you can't rebuild it yourself. If your having trouble buying a battery because they cost to much, then ab RX-7 may not be the right car.
10-20-13, 04:41 PM
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If I am going to keep this engine, I would like to rebuild it and try and do some preventative maintenance. I have been told/have been reading that rotary engines are terribly unreliable and break all the time.
I am wondering what are some good ways to keep the engine running well. I would think that new apex seals and gaskets would be a good start, and I should probably look at some new rotary housings, but is there anything else I should think about?
Oh, and how exactly does the 12a have good gas mileage? According to a lot of sources, the gas mileage is less than 20MPG
10-20-13, 04:52 PM
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I have a couple of questions. Since your a college student, you're a smart guy. I can understand not having much money. How much research did you do before the purchase? Do you know how much a rebuilt engine is going to cost? If it where me in your situation, try and find a cheap used 12A. The aren't very easy to find. The last 12A engine I had rebuilt cost me $1500 and I supplied all the parts ($5000 total). I'm guessing you can't rebuild it yourself. If your having trouble buying a battery because they cost to much, then ab RX-7 may not be the right car.
The original idea was to get an extremely light car and put in a super fuel efficient engine for college. As the years went on, I would add some modifications to the car, and eventually I would going to build this up to be a kit car.
My friend was relocated because of work (several states away), and now I am stuck with a car with no prior automotive skills.....yay.
I myself am also in engineering as well (biomed/mechanical), so I have a good grasp on how engines (especially rotary engines) work. Therefore I have confidence that I can do the work that I need to myself, but I am horribly uninformed about things like what engine will fit in what car and what companies make good quality parts. Stuff like that.
The thing about cost is that I do a lot of stock trading which means I can get the money for certain bits and bobs, but I never have a huge amount of cash on hand. Generally speaking I can only spend 1K every 2-3 months.
Like most things in life, I CAN do this, it is just going to be a very steep uphill battle.
To answer your question directly...Yes I did my research, and it was indeed a smart choice.....before my friend moved away. Then I was screwed royally.
Edit: the only reason I do not have a battery is simply because I know the battery will be sitting in the car for a while as I rebuild it, so I do not want to buy a 100 dollar battery until the car is 100% road worthy.
Last edited by Tjj226_Angel; 10-20-13 at 04:54 PM.
10-20-13, 07:10 PM
#7
Ah yes. Originally my friend was going to help me rebuild this since he was a mazda mechanic and majored in automotive engineering. He even helped me pick it out.
The original idea was to get an extremely light car and put in a super fuel efficient engine for college. As the years went on, I would add some modifications to the car, and eventually I would going to build this up to be a kit car.
My friend was relocated because of work (several states away), and now I am stuck with a car with no prior automotive skills.....yay.
I myself am also in engineering as well (biomed/mechanical), so I have a good grasp on how engines (especially rotary engines) work. Therefore I have confidence that I can do the work that I need to myself, but I am horribly uninformed about things like what engine will fit in what car and what companies make good quality parts. Stuff like that.
The thing about cost is that I do a lot of stock trading which means I can get the money for certain bits and bobs, but I never have a huge amount of cash on hand. Generally speaking I can only spend 1K every 2-3 months.
Like most things in life, I CAN do this, it is just going to be a very steep uphill battle.
To answer your question directly...Yes I did my research, and it was indeed a smart choice.....before my friend moved away. Then I was screwed royally.
Edit: the only reason I do not have a battery is simply because I know the battery will be sitting in the car for a while as I rebuild it, so I do not want to buy a 100 dollar battery until the car is 100% road worthy.
The original idea was to get an extremely light car and put in a super fuel efficient engine for college. As the years went on, I would add some modifications to the car, and eventually I would going to build this up to be a kit car.
My friend was relocated because of work (several states away), and now I am stuck with a car with no prior automotive skills.....yay.
I myself am also in engineering as well (biomed/mechanical), so I have a good grasp on how engines (especially rotary engines) work. Therefore I have confidence that I can do the work that I need to myself, but I am horribly uninformed about things like what engine will fit in what car and what companies make good quality parts. Stuff like that.
The thing about cost is that I do a lot of stock trading which means I can get the money for certain bits and bobs, but I never have a huge amount of cash on hand. Generally speaking I can only spend 1K every 2-3 months.
Like most things in life, I CAN do this, it is just going to be a very steep uphill battle.
To answer your question directly...Yes I did my research, and it was indeed a smart choice.....before my friend moved away. Then I was screwed royally.
Edit: the only reason I do not have a battery is simply because I know the battery will be sitting in the car for a while as I rebuild it, so I do not want to buy a 100 dollar battery until the car is 100% road worthy.
One word of caution about rebuilding the current 12A in your car. It is hard to find good 12A housings, especially in a car like yours that has so many miles. It takes about 4-5 core engines just to find two good housings. They don't make 12A rotor housing any longer, but some companies are starting to mill down 13B housings. Atkins has these at $600 each. A rebuild kit will cost ~$800 and that doesn't include everything that might be needed.
Before tearing down the current engine, you might remove the intake manifold and check the condition of the o-rings. They could be the cause of the water out the tailpipe.
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10-21-13, 10:14 AM
#8
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I did have a thought. My school has a fairly decent metal shop. Provided that my housings do have scratches in them, is it possible to fill the cracks with molten aluminium and then grind down the walls to be flush?
10-21-13, 10:27 AM
#9
You'll never know if you have bad housing until you disassemble the engine. Try everything you can to bring the engine back to life before resorting to a tear down.
Just to give you an idea, this 1985 in Libertytown, VA is only $2000 and it runs. http://frederick.craigslist.org/cto/4090334604.html. If you goal is to learn and be willing to spend money during the process, then a rebuild can be a fun learning experience and results in the satisfaction of knowing you did it. On the other hand, if your goal is to have a cool RX-7 at a decent price, finding one like this example is the way to go. I've spent over $7000 getting my 1985 to the point it is at and after 13 years it still is not on the road --- dam OCD. I'll never recoup that investment but I don't care. My goal was to have something that I did myself and could learn and look back on the experience.
10-21-13, 12:01 PM
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The issue is generally flaking chrome. Once this starts it can ruin a housing. There are several places that apply a special coating to restore them. Adding aluminum will not work. The interior surface needs to be harder then aluminum and the specs for clearance are so high that no one has developed a surefire way of restoring them yet. If someone could, they would be in the money.
You'll never know if you have bad housing until you disassemble the engine. Try everything you can to bring the engine back to life before resorting to a tear down.
Just to give you an idea, this 1985 in Libertytown, VA is only $2000 and it runs. 1985 Mazda RX7. If you goal is to learn and be willing to spend money during the process, then a rebuild can be a fun learning experience and results in the satisfaction of knowing you did it. On the other hand, if your goal is to have a cool RX-7 at a decent price, finding one like this example is the way to go. I've spent over $7000 getting my 1985 to the point it is at and after 13 years it still is not on the road --- dam OCD. I'll never recoup that investment but I don't care. My goal was to have something that I did myself and could learn and look back on the experience.
You'll never know if you have bad housing until you disassemble the engine. Try everything you can to bring the engine back to life before resorting to a tear down.
Just to give you an idea, this 1985 in Libertytown, VA is only $2000 and it runs. 1985 Mazda RX7. If you goal is to learn and be willing to spend money during the process, then a rebuild can be a fun learning experience and results in the satisfaction of knowing you did it. On the other hand, if your goal is to have a cool RX-7 at a decent price, finding one like this example is the way to go. I've spent over $7000 getting my 1985 to the point it is at and after 13 years it still is not on the road --- dam OCD. I'll never recoup that investment but I don't care. My goal was to have something that I did myself and could learn and look back on the experience.
One would think that there is a way to repair these housings though. Who knows though. Maybe this is just an engine sent from the heavens and it just needs some new apex seals to be on the safe side.
In any case I know for a fact that the engine will need some type of work done to it before I trust my life to it. Even if it is preventative maintenance. However, I certainly will start with the O-rings.
10-25-13, 11:24 PM
#11
If it's your first rotary powered car, and within your first few months of owning the car - I'd swap the same engine back into it. So 12a -> 12a again - no need to do wiring swaps, just plug and play.
Like KCREPU says, it's hard to find a used 12a that runs and it's hard to find housings for them as well. It's up to you to choose which way you'd like to go with the car and how much you want to put into it.
Like KCREPU says, it's hard to find a used 12a that runs and it's hard to find housings for them as well. It's up to you to choose which way you'd like to go with the car and how much you want to put into it.
10-26-13, 06:57 AM
#12
Sounds like the simple and cheap path is an intake manifold gasket and the orings that go with it.
If it starts and runs but still puts water out the tailpipe, alumaseal can work wonders.
The mileage on the engine is a lot, but some simple tlc may get her through til you find a suitable replacement.
If it starts and runs but still puts water out the tailpipe, alumaseal can work wonders.
The mileage on the engine is a lot, but some simple tlc may get her through til you find a suitable replacement.
11-12-13, 06:39 PM
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Ok guys, update time.
So after getting a battery, new spark plugs, and flushing out the fluids, it runs : D
The rotary housings are also in miraculous condition. I think I might be able to get away with sending the rotary housings out to be re-chromed and call the engine good.
But this raises a new question. What can I do to increase engine efficiency. I am not talking about going from a 110hp engine with 12MPG to 180hp with 30MPG. However, I would like to make a little step in that general direction.
What is the best mod to increase the efficiency? I see that a lot of people suggest modding the exhaust and the carburetor. What about the fuel pump, or body parts that can be replaced with light weight parts for a decent price?
I am just looking on setting sort of a road map for tuning my car so that I don't break the bank completely. : )
So after getting a battery, new spark plugs, and flushing out the fluids, it runs : D
The rotary housings are also in miraculous condition. I think I might be able to get away with sending the rotary housings out to be re-chromed and call the engine good.
But this raises a new question. What can I do to increase engine efficiency. I am not talking about going from a 110hp engine with 12MPG to 180hp with 30MPG. However, I would like to make a little step in that general direction.
What is the best mod to increase the efficiency? I see that a lot of people suggest modding the exhaust and the carburetor. What about the fuel pump, or body parts that can be replaced with light weight parts for a decent price?
I am just looking on setting sort of a road map for tuning my car so that I don't break the bank completely. : )
11-13-13, 11:33 PM
#15
you could do a direct fire ignition setup would help with your mileage quest best i got on a stock setup was 26-23mpg hiway 150miles a day
you should look in the 1st gen archives for info and the faq if you havent looked https://www.rx7club.com/1st-generati...q-page-237777/
you should look in the 1st gen archives for info and the faq if you havent looked https://www.rx7club.com/1st-generati...q-page-237777/
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