Rotary baja new engine
09-30-07, 05:19 PM
#1
Rotary baja new engine
Remember this baja from my web page?
It's time for a new engine. One built for NA torque! It'll be a torque monster!
Oh it still runs... it's just streetported with a holley and doesn't perform well enough. That's why we want a non ported 13B and a stock carb with proper jets and air bleeds.
A rotary in a baja you ask? What is the point? How can you build it for torque? Fortunately I still have some engine parts that came out of a Rotary Parkway 26 - a 26 passenger bus in Japan back in '74. Or maybe it was a delivery van? Either way, that engine was built for mondo torque and extended periods at low RPM that would foul a 1st gen engine. It was such an oddity I ended up memorizing everything about it. Therefore I can recreate it. That's fortunate for the owner, don't you think? 8)
He had this durkee ***** port engine sitting on the shelf for a few years so it is what we'll use for the rotating assembly and carb. Never fired up, which is probably a good thing.
Can't use the side plates because he already effed 'em up. Sucks.
I guess the camera can't really capture the ugly hack job in there. I'll take another picture after it's dissassembled. Y plates front and rear with a tall port nitrided R5 intermediate. They can be saved and streetported for another project.
The new side plates will consist of the exact same port timing as the bus/van engine. Same intake manifold too (which is important, as you'll see later).
As for the rotor housings, if they're good ie not butchered too much with good chrome, they might be used. Otherwise we'll have to get some GSL-SE housings because their port timing is identical to the bus engine - the exhaust port opening timing is critical for this project to work as intended. These current housings look like the openings are what we want and have been left alone. If so, that's good. Hopefully the closings aren't too far. I'll know more once it's apart.
Check out a couple vids shot earlier this year. My personal goal is for the owner to throw roosters twice as big with the new engine. Call me confident.
https://www.rx7club.com/forum/showthread.php?t=624151
It's time for a new engine. One built for NA torque! It'll be a torque monster!
Oh it still runs... it's just streetported with a holley and doesn't perform well enough. That's why we want a non ported 13B and a stock carb with proper jets and air bleeds.
A rotary in a baja you ask? What is the point? How can you build it for torque? Fortunately I still have some engine parts that came out of a Rotary Parkway 26 - a 26 passenger bus in Japan back in '74. Or maybe it was a delivery van? Either way, that engine was built for mondo torque and extended periods at low RPM that would foul a 1st gen engine. It was such an oddity I ended up memorizing everything about it.
Therefore I can recreate it. That's fortunate for the owner, don't you think? 8)He had this durkee ***** port engine sitting on the shelf for a few years so it is what we'll use for the rotating assembly and carb. Never fired up, which is probably a good thing.
Can't use the side plates because he already effed 'em up. Sucks.
I guess the camera can't really capture the ugly hack job in there. I'll take another picture after it's dissassembled. Y plates front and rear with a tall port nitrided R5 intermediate. They can be saved and streetported for another project.
The new side plates will consist of the exact same port timing as the bus/van engine. Same intake manifold too (which is important, as you'll see later).
As for the rotor housings, if they're good ie not butchered too much with good chrome, they might be used. Otherwise we'll have to get some GSL-SE housings because their port timing is identical to the bus engine - the exhaust port opening timing is critical for this project to work as intended. These current housings look like the openings are what we want and have been left alone. If so, that's good. Hopefully the closings aren't too far. I'll know more once it's apart.
Check out a couple vids shot earlier this year. My personal goal is for the owner to throw roosters twice as big with the new engine. Call me confident.
https://www.rx7club.com/forum/showthread.php?t=624151
09-30-07, 07:30 PM
#4
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Jeff, I don't know what happened to those videos. It certainly isn't the length of time they've been on there, since I have older stuff. They still show up on my media page. I guess I'll just have to upload them again, assuming I can find them.
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10-02-07, 02:21 PM
#9
Thanks everyone. And BASTARD, what good is a mid engine setup when the 13B fits fine where it is?
I've got some news. The exhaust ports were indeed opened a little sooner. That sucks. I need to compare them to a stock port and see how much damage was done. I had hoped to save the owner a little bit of money but he may just have to get a set of GSL-SE rotor housings.
I've got some news. The exhaust ports were indeed opened a little sooner. That sucks. I need to compare them to a stock port and see how much damage was done. I had hoped to save the owner a little bit of money but he may just have to get a set of GSL-SE rotor housings.
10-07-07, 01:08 AM
#13
I got the 13B apart. I had to employ the old 1" hole saw trick to weaken the front bolt because all other methods failed. I even bent my counterweight stopper applying like 800 foot pounds or some obscene number (think of two 4 foot pipes pulled together with as much force as I could muster). No dice. Almost killed a beefy 1/2" breaker bar (it really twisted but appears to be ok).
All it took was several minutes with a hole saw around the 19mm bolt, cutting about half way through the flat section, trying with the 1/2" impact a couple times along the way. I assumed I'd have to cut all the way through it but nope, only about half way was all it took. As soon as it was weakened it came off like it should. There wasn't even any locktight or other thread locker holding it on. This thing was on with shear Thor power.
Ken, if you're reading this, you overtightened the front bolt man! These old 13Bs only require about 70 or 80 foot lbs. Not 700 or 800. lol
All it took was several minutes with a hole saw around the 19mm bolt, cutting about half way through the flat section, trying with the 1/2" impact a couple times along the way. I assumed I'd have to cut all the way through it but nope, only about half way was all it took. As soon as it was weakened it came off like it should. There wasn't even any locktight or other thread locker holding it on. This thing was on with shear Thor power.
Ken, if you're reading this, you overtightened the front bolt man! These old 13Bs only require about 70 or 80 foot lbs. Not 700 or 800. lol
10-09-07, 01:50 PM
#14
I picked up the core and dragged it home. I'll tear it down at some point. It's a 1st gen 12A with some interesting features. Looks to have been rebuilt at some point because the rotor housings don't match. One is US-spec and the other is from a nitrided R5! Also it had a beehive but the rear plate had a threaded in heater core fitting so somebody welded part of a T fitting onto an old style fitting so the beehive could be used. The side plates are all Y castings and look fully compatible with the baja. I won't bore you with any more details.
11-05-07, 01:29 PM
#15
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karism what kind of transmission have you mated the 13 b to? just wondering B/c your another of very few people who both have a passion for both VEEDUBS AND RX7/ROTARIES which are both equally awesome transaxles out of the bus wont die the one's mated two type four vdubs are great good luck with both aspects of the project there!
88 FC3S vert N/A
88 FC3S vert N/A
11-05-07, 07:34 PM
#16
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I picked up the core and dragged it home. I'll tear it down at some point. It's a 1st gen 12A with some interesting features. Looks to have been rebuilt at some point because the rotor housings don't match. One is US-spec and the other is from a nitrided R5! Also it had a beehive but the rear plate had a threaded in heater core fitting so somebody welded part of a T fitting onto an old style fitting so the beehive could be used. The side plates are all Y castings and look fully compatible with the baja. I won't bore you with any more details.
11-24-07, 12:27 PM
#17
The side plates turned out to have too much step wear. 
We located a 3 rib tranny which has 5.3 or so gearing. This will work with the current baja's engine's streetporting better than the 4.86 5 rib it currently has. We'll swap trannies before any engine work is done. I have a feeling the gearing change is the solution, not an engine change.
We located a 3 rib tranny which has 5.3 or so gearing. This will work with the current baja's engine's streetporting better than the 4.86 5 rib it currently has. We'll swap trannies before any engine work is done. I have a feeling the gearing change is the solution, not an engine change.
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