VW Baja ROTARY install

Jeff20B · 10-18-2008, 03:28 PM

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Jeff20B · 10-18-2008, 03:45 PM

The old setup had to go because it consisted of a tall geared bug tranny (3.88 and big tires with a gutless engine = no no) and the engine was a1600 dual port but had a 1500 single port carb adapted to it. It ran out of breath by 4k and had an annoying flat spot just off idle. It only had power between 2k and 3k. Above or below was gutless.

I picked up a 3 rib bus tranny 002 model from a '77 or so. It has the extra mounting ears on top of the bellhousing if you know what I'm talking about. It should have a much better 5.37 or something ratio.

and a mounting kit

a KEP adaptor

and flywheel (used, obviously)

Jeff20B · 10-18-2008, 03:51 PM

Getting the tranny in.

Jeff20B · 10-18-2008, 03:56 PM

Building engine

Jeff20B · 10-18-2008, 04:09 PM

Stock port timing. I rounded the sharp 90° edges and left a rough surface. I can't wait to see how it performs.

Jeff20B · 10-18-2008, 04:24 PM

All done.

Test fitting a spare rear plate and a beehive oil cooler.

I had to pound the sheet metal in a little.

Why use a beehive you ask? They work fine if you know what you're doing. Far easier to deal with as well since there is no seperate oil cooler to install, plumb lines, fab cooling fans for it etc.

Ready to install.

In.

djmtsu · 10-18-2008, 05:45 PM

Looking sweet. Can't wait to see a vid!

TehMonkay · 10-19-2008, 02:29 PM

12A plates with 13B housings?

Rogue_Wulff · 10-19-2008, 03:02 PM

I'm guessing it's an early 4 port 13B. Knowing Jeff's supply of early engines and parts, it wouldn't surprise me one bit if the entire engine was from the mid 70's. I know the rotor housings are vintage 70's, due to the TR ports by the exhaust ports.

Jeff20B · 10-20-2008, 03:42 PM

Thanks for posting, guys. I like feedback.

Turns out my bus tranny is closer to a '74 year model. It ought to work out fine with a rotary.

The Wulff is almost correct. The only parts that aren't vintage '70s are the side plates and front cover. Dizzy and alt, too. The side plates are nitrided Y castings from an FB and so is the front cover (the OMP is the leaner type but I can jack it open more with a couple washers). The rotor housings are from a delivery van or the Parkway Rotary 26 (a 26 passenger bus in Japan), or possibly from a JDM Cosmo or Luce from perhaps 1975 as far as I could tell from the original parts that made up this engine. I upgraded key areas where I saw fit.

1. Nitrided Y side plates offer less friction/wear/heat/weight.
2. New side seals with around .001" clearance for really tight gas sealing. For naturally aspirated use only (you'd want at least .003" for boosted applications).
3. FC aluminum waterpump housing and aftermarket FB aluminum GMB impeller for maximum weight savings (only recommended with an electric fan because a clutch fan stresses the waterpump housing).
4. '76 Cosmo reversed runner intake manifold for longer primary runners which should equate to more torque. Matching carb with correct air bleeds and fuel jets for good driveability from idle up to 6 or 7k or whatever red line is on a Cosmo.
5. Stock intake port timing for maximum low RPM torque and driveability. All sharp 90° edges and casting flash were smoothed so hopefully it retains enough turbulence at low RPM to keep a strong idle. High RPM total flow should be improved over stock.

One feature of the original engine I kept is the '75-'85 1757 rotating assembly which was the heaviest stock rotor set; perfect for low RPM torque.

I also kept the exhaust ports stock. They had the late opening later closing port timing of a GSL-SE, which apparently is best for low RPM torque because the delay in opening provides more time for the expanding gasses to push the rotors and shaft around, but supposedly peaks in effectiveness by 4k RPM. Fair enough.

I went with an RX-4 radiator and drilled new stock Mazda thermostat. Two electric fans, one pusher one puller, should cool well enough. They will be installed where space permits allowing as short a rear push bar as possible to reduce 'moment'. It now protrudes just 3 inches more rearward than with the bug engine.

Jeff20B · 10-20-2008, 04:03 PM

I got the radiator mounts tacked in place.

WE3RX7 · 10-20-2008, 06:57 PM

This looks like fun! That should make for a great bug engine too, who needs 7-8k on those things, it's going to wheelie enough as it is!

Jeff20B · 10-23-2008, 01:15 PM

One can only hope. I finished up all the welding yesterday. It's inspection and paint time today.

PercentSevenC · 10-23-2008, 01:27 PM

Looks like you got the radiator situation figured out nicely. Fuel pump and lines look good, too. I'll have to come over to check it out sometime.

Jeff20B · 10-24-2008, 03:52 PM

Yeah, everything went in nicely although it took a while to get it that way. I'm better at left brain stuff than all this artistic right brain 'engineering' stuff.

The exhaust is done. Next is electrical.

10-18-2008, 03:28 PM	#1
Jeff20B Rotary Fanatic Join Date: Mar 2008 Posts: 215 Rep Power: 18	· Last edited by Jeff20B; 12-29-2008 at 02:36 PM.

10-18-2008, 05:45 PM	#7
djmtsu My minds tellin' me no... Join Date: Feb 2008 Location: Murfreesboro, TN Posts: 4,043 Rep Power: 22	Looking sweet. Can't wait to see a vid! __________________ 1976 Mazda Cosmo RX-5 1976 Mazda Cosmo RX-5 2003 Toyota Tundra TRD 2015 Toyota 4Runner SR5

10-19-2008, 02:29 PM	#8
TehMonkay Rotary Fanatic Join Date: Apr 2008 Location: Louisville, KY Posts: 302 Rep Power: 18	12A plates with 13B housings? __________________ My car blows up everytime I start it, it's rotary

10-20-2008, 03:42 PM	#10
Jeff20B Rotary Fanatic Join Date: Mar 2008 Posts: 215 Rep Power: 18	Thanks for posting, guys. I like feedback. Turns out my bus tranny is closer to a '74 year model. It ought to work out fine with a rotary. The Wulff is almost correct. The only parts that aren't vintage '70s are the side plates and front cover. Dizzy and alt, too. The side plates are nitrided Y castings from an FB and so is the front cover (the OMP is the leaner type but I can jack it open more with a couple washers). The rotor housings are from a delivery van or the Parkway Rotary 26 (a 26 passenger bus in Japan), or possibly from a JDM Cosmo or Luce from perhaps 1975 as far as I could tell from the original parts that made up this engine. I upgraded key areas where I saw fit. 1. Nitrided Y side plates offer less friction/wear/heat/weight. 2. New side seals with around .001" clearance for really tight gas sealing. For naturally aspirated use only (you'd want at least .003" for boosted applications). 3. FC aluminum waterpump housing and aftermarket FB aluminum GMB impeller for maximum weight savings (only recommended with an electric fan because a clutch fan stresses the waterpump housing). 4. '76 Cosmo reversed runner intake manifold for longer primary runners which should equate to more torque. Matching carb with correct air bleeds and fuel jets for good driveability from idle up to 6 or 7k or whatever red line is on a Cosmo. 5. Stock intake port timing for maximum low RPM torque and driveability. All sharp 90° edges and casting flash were smoothed so hopefully it retains enough turbulence at low RPM to keep a strong idle. High RPM total flow should be improved over stock. One feature of the original engine I kept is the '75-'85 1757 rotating assembly which was the heaviest stock rotor set; perfect for low RPM torque. I also kept the exhaust ports stock. They had the late opening later closing port timing of a GSL-SE, which apparently is best for low RPM torque because the delay in opening provides more time for the expanding gasses to push the rotors and shaft around, but supposedly peaks in effectiveness by 4k RPM. Fair enough. I went with an RX-4 radiator and drilled new stock Mazda thermostat. Two electric fans, one pusher one puller, should cool well enough. They will be installed where space permits allowing as short a rear push bar as possible to reduce 'moment'. It now protrudes just 3 inches more rearward than with the bug engine. Last edited by Jeff20B; 10-20-2008 at 03:46 PM.

10-19-2008, 03:02 PM	#9
Rogue_Wulff Non Member Join Date: Jun 2008 Posts: 310 Rep Power: 17	I'm guessing it's an early 4 port 13B. Knowing Jeff's supply of early engines and parts, it wouldn't surprise me one bit if the entire engine was from the mid 70's. I know the rotor housings are vintage 70's, due to the TR ports by the exhaust ports.

10-20-2008, 06:57 PM	#12
WE3RX7 RCC Addict Join Date: Feb 2008 Location: VA Posts: 1,812 Rep Power: 19	This looks like fun! That should make for a great bug engine too, who needs 7-8k on those things, it's going to wheelie enough as it is!

10-23-2008, 01:15 PM	#13
Jeff20B Rotary Fanatic Join Date: Mar 2008 Posts: 215 Rep Power: 18	One can only hope. I finished up all the welding yesterday. It's inspection and paint time today.

10-24-2008, 03:52 PM	#15
Jeff20B Rotary Fanatic Join Date: Mar 2008 Posts: 215 Rep Power: 18	Yeah, everything went in nicely although it took a while to get it that way. I'm better at left brain stuff than all this artistic right brain 'engineering' stuff. The exhaust is done. Next is electrical.