Other Engine Conversions - non V-8 Discussion of non-rotary engines, exc V-8's, in a car originally powered by a Rotary Engine.

Engine swap idea, constructive opions accepted!

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Old 09-20-07, 11:41 AM
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Lightbulb Engine swap idea, constructive opions accepted!

About three weeks ago I was cursed... err blessed with a free 1993 Mazda 929 sedan. It is a runner that required some suspension bits and some tune up components to make it driveable. The PO claimed the fuel pump was bad, but after autocrossing it last weekend I was certain that there was an ignition problem.

Yesterday morning one of my customers was looking at the car and asked how much I like Mazdas... I said "a little." (FB, FC, NA, NA, Courier, REPU now this). He mentioned that he had just had triple bypass surgery and needed someone to help him with removing an 88K mile drivetrain from a little red FB. i went to go look at the car and he said I could have the low miler for pulling the engine.

So I am thinking that the FB needs a 205hp JE-ZE DOHC 3.0L from the 929.

The North American 929 was only sold with an automatic, but the MPV was sold with a manual and the bells are the same. I need to find out the point where the shifter comes through the floor on the FB versus the MPV trans. The actual transmission from a FC RX7 can be used with the MPV bell as well if I need a shifter mounted farther back.

The engine is obviously heavier than the 12a, but imagine a Mazda powered RX7 with torque! I am seriously considering doing this over my upcoming 11 day vacation.

Any suggestions? Tips? Support?

Last edited by QuasiMofo; 09-20-07 at 11:47 AM. Reason: update
Old 09-20-07, 12:08 PM
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A Mazda powered RX-7 with torque you say?

I've worked on 1st gens enough to know I'd never want to put a boinger in one. Having said that, I'm just starting a 20B install in one and have been working on a 4 rotor install in another for a while now (the important bits are almost done). My friend has daily driven a supercharged 4 port 13B for several years.

That's how you get torque in a 1st gen keeping it Mazda powered.
Old 09-20-07, 12:09 PM
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Very intersting swap (Not bashing but it should be in the Non rotary engine swap section).

Not sure how doable this is to do in 11 days neither. You will need to custom fab all the work as i doubt you'll find anything. I have a feeling that the transmission might be sticking back a little too far too (depending on engine mounting position)
Old 09-20-07, 12:15 PM
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If you have to use the MPV bell housing, then your only choice for a tranny is one from a TII. The NA trannys do not have a separate bell housing. Whether the MPV will mate with the TII tranny is another question. If this engine came in the Mazda trucks, that may be the route to go for a tranny.
Old 09-20-07, 12:26 PM
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[QUOTE=dj55b;7351068](Not bashing but it should be in the Non rotary engine swap section).[QUOTE]

Crapzzorrs, I thought I did post it in there!

If a MOD can move this it would be appreciated.
Old 09-20-07, 12:42 PM
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I've never seen the MPV with the manual... I've only heard of it... Those that I've heard of with the manual had the 2.6L I4 engine found in the B2600i trucks...

Interesting idea, but there are more powerful, lighter engines available.

Good luck with the swap though.
Old 09-20-07, 01:07 PM
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Originally Posted by trochoid
If you have to use the MPV bell housing, then your only choice for a tranny is one from a TII. The NA trannys do not have a separate bell housing. Whether the MPV will mate with the TII tranny is another question. If this engine came in the Mazda trucks, that may be the route to go for a tranny.
The Luce (Asian 929) is originally equipped with a 13B, think of it as a funky RX7 sedan. The 3.0L V6 was available with a manual but not in the US and not in the last 929. The previous generation had both a 13B and 3.0L V6 5 speed. The Luce 13B transmission is the same as the Luce 3.0L V6 transmission but the bells are different. The MPV bell is the same as the Luce V6 bell. The TII RX7 trans is similar to the Luce trans with the exception of the shifter placement (RX7 is farther rearward) The MPV trans is similar to the Luce trans except its shifter sits farther forward.

I need to figure out the FB transmission length and shifter location, then crunch the position between the three transmission options to determine which box I need to use.

As far as fitting it into 11 days, it is doable if I am motivated. The RX7 will already be stripped and the dash will be removed JIC. The 929 would be stripped in a day, cleaning and mock up in three days, measuring and mocking up the driveshaft, final welds, grinding and paint in one more more day, dropping in the harnesses, refitting the engine and pegging the wires two days, fuel system in one day. Exhaust will be shipped out, but even if I get a little distracted I should be able to finish the hard parts within schedule.

I would love to do a 13B or 20B swap BUT if I can pull this off for less than $500.00 out of pocket plus the manual transmission I will be pretty happy.
Old 09-20-07, 01:19 PM
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I'd say sell the piston stuff and get a cheap rotary. They do exist. You just have to look in the right places.
Old 09-21-07, 01:06 AM
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I agree... with Jeff, save or sell the cylinder and use rotary. In my opinion, the main reason that I love my Rx-7 is because its got such a strange engine in it. I have had some weird guys tell me to drop and LS1 and try to shove a supra engine in it... but I tell them, 'My car is special, it has a rotary engine, why should I ruin it with an engine you see everyday?'
Old 09-21-07, 10:25 AM
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Originally Posted by DemonSpawn67
I agree... with Jeff, save or sell the cylinder and use rotary. In my opinion, the main reason that I love my Rx-7 is because its got such a strange engine in it. I have had some weird guys tell me to drop and LS1 and try to shove a supra engine in it... but I tell them, 'My car is special, it has a rotary engine, why should I ruin it with an engine you see everyday?'
Because the car is still special WITHOUT the rotary. You guys seem to feel that the car itself is worthless without the rotary, which explains why they are so cheap when the engine dies.

The rest of us think the chassis is outstanding, with excellent styling, excellent ergonomics, excellent suspension, excelent handling, and light weight, and has been proven to retain all those qualities with other engines swapped in. Therefore, it follows that the main reasons we love the RX7 have nothing to do with the engine, but with the 90% of the car that ISN"T the engine. You guys love the 10% that IS the engine and really couldn't care less about the car that the engine is in. And you always want to spend more to get less, as far as results are concerned. Fine for you, but the rest of us prefer to spend less to get more.

And the RX7 chassis is one of the best ways in automobiledom to do that.
Old 09-22-07, 01:03 PM
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I guess going through with this, I would have to be nice to the rotary lovers and rebadge the car as a MX7!

Considering that the car is free only if I gut it and I there is very little interest in the parts on the 929 (the free one in question would make a 50 peso TJ pro look great) The only redeeming part of the whole car is the sweet sounding DOHC V6 mill and a new transmission. They aren't worth much outside of the people who want them for free.
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