auricom

Trying to fit a 13b into a 1989 Nissan 240sx:
I made a mock up using parts from a spare 13b. I just put together the housings, front cover, oil pan, and transmission. I also threw the stock mounts on. I made this mock up just to figure out how I am going to wedge the good 13b engine into the 240sx bay. My problem right now is that the 13b will be situated so that its front rotor housing will be directly over the sub frame cross member, and this causes interference issues in 2 spots. First, the oil pan is hitting the cross member. To raise the engine up higher would not only result in an undesirable CG and drive yoke angle, but I would probably have to cut a hole in the hood for the intake manifold! The second point of interference is the steering linkage getting in the way of the driver side motor mount. So fabing together a new motor mount won't be a cinch, but we're not too worried about it. My main concern is the oil pan. not being experts on the 13b, but having a pretty good understanding of the workings of an oil system, my friends and I are thinking that we can get a piece of 1/4 in steel and machine it to sever as both the new oil pan, and the base frame for motor mounting. we are still working out the details as to exactly how we are going to link the oil plate to the 240 sub frame motor mounts (we will have some sort of rubber dampening) but I was wondering if anyone has heard of anybody doing anything like this to the oil system of a 13b before? I found an aviation guy that put a similar structural system into a plane:

http://www.rotaryeng.net/B-Trubee-mm.jpg

But I was wondering if anyone has tried it in a car? And no, we are not JUST going to cover the bottom of the 13b with a steel plate! We are planning on mounting the steel from the back of the 13b and cutting it off near the front rotor housing, and then we will fabricate a little protrusion from the volume above the plate and under the 13b. The protrusion will have a slightly downward angle (there is plenty of room for this here) and we will simply turn the oil suction nozzle (which comes off the bottom of the front cast housing) around on its flange. This protrusion will serve as the new primary volume for the oil pan, and here we will drill and tap a drain hole, and mount oil level sensor. Can anyone think of any reason why we would have oil flow issues with a set up like this?

TonyD89

iTrader: (10)

The front plate is also where the oil pick-up is located. I guess it depends on how far back you want to cut into the pan ( am I assuming wrongly that this is what you want to do?). You have a little room to play with. Unlike piston engines there is nothing rotating above the sump. As long as drainage,pick-up, and capacity are taken into acount, there is room for modification.

crispeed

I know of one guy localy who has done the conversion in the same car. He had no issues you're mentioning and used all mazda parts except for a set of custom engine mounts.
I'm not to familar with the 240 crossmember. Does the crossmember require the sump to be in the rear or the front?
There are so many different combinations of parts you can use to do this conversion. Mazda had mounting locations just about on every position of the motors not to mention oil pan sump locations. You have to decide which combination or parts are needed.
For most conversions of this nature the front cover from a 84-85 12A or 13B offers the easiest practical mounting location. Coupled that with the 13B GSL-SE oil pan either mounted in the stock location with the sump in the front or in a reversed position with the use of a custom oil pickup.
Some pics of the crossmember would help.

auricom

Thanks for the input, i'll try and get some pics online this evening.
To attempt to clairify, the intended mounting locations for the 13b i have (i think its a 87) are both on the central housing. The passenger side mount attaches to the bottom surface of the central housing, the driver side mount is on the side of the central housing. While it is impossible for me to use the stock 13b mounts themselves, i had the full intention of fabricating some of my own mounts that attach to the 13b in the stock LOCATIONS. are you saying that this may not be necessary? do some rotaries have different front covers with holes drilled for the motor mounts to mate with? i was under the impression that all 2rotar rotaries required that the engine be connected to the chassis via the central housing. if i can get a front cover to mount with, that would be great! that would take care of all of my problems i think. do you think i could weld some bracketry to my front cover instead of purchassing an 84-85 front cover in order to mount?

With regard to the oil pan: I really dont think there is any good place for me to put the 13b into the 240 bay if i retain the stock pan. i'm either going to have to change my crossmember (last resort) or make a new, much shallower oil pan. so shallow that its a plate in fact. i found another aviation guy that used a plate like this:

http://bbushong.tripod.com/Twinstar.htm

look about 50%-75% down the page. I am wondering what thoes small holes are for. But like i said in my first post, the ENTIRE bottom surface will not be covered with the plate, just the part above the 240 crossmember and back. in front of the crossmember will be a volumous downward protrusion of the oil "pan" where the bulk of the oil will be contained. I'll try to post pics soon

Thanks again.

TonyD89

iTrader: (10)

That plate in the photo in the link is used with the oil pan. The large holes are for oil draining out of the plates to reach the sump. There is an oil drain in the rear plate that has to stay connected to the sump but mybe you can figure some other way to keep the flow?

auricom

Well i took a closer look at what i was working with by putting the mock-up 13b back into the bay. this time i attached the major components of the intake manifold to check upper clearance. its going to be very close, but that big plenum should fit in there nicely. i did see a problem with my initial longitudinal placement however. the way i had it, the front rotor exhaust port would have been very close to the 240's subframe mount location, making any type of header impossible to fit. i decided to push the 13b as far back as i possibly could without the transmission attached, giving both exhaust ports the clearance they need. i'm going to have to cut into the firewall a bit more than i had originally planed to fit the tranny, but since we will be reinforcing everything with rollcage, i'm going to try and not worry about structural consequences. with the current plan of placement, the oil pan would have plenty of room in the back, but there still is a clearance problem with the steering linkadge in the middle, and the subframe in the front (i've only got about 2 inches in both spots). the front is particularly toublesome, since now i'm going to have to fabricate a new oil suction tube. the tube will come out of the front housing, then imediately shoot back to the underside of the rear rotor housing, where it will drop into the oil, which will be contained in a fabricated pan, or possibly the original pan, with a bit of dept cut from the front/middle. i'm going to try and get my engine "craddle" finished up this week and post some pics. wish me luck...