So I am trying to fit this 13b Renesis Rotary from into my 1976 Fiat 124 and I'm having some trouble, main reason being the oil pan/subframe because the old one looks like this: 
and the new one: 
Notice the difference between where the bottom of the oil pan is and where the bottom of the bell housing is. So whats the plan? I have some different ones, main plan being remake the entire center section of of the subframe which I can do but if anyone has some better plans I wanna hear em. There really are no other oil pans that would give me enough clearance so that's out. In its current state as you see in the picture suspened by an engine hoist it is about 4 inches too high and and 4 inches too far forward from where I want it. The transmission tunnel is not really a problem here Other than the fact that I want to keep the stock tunnel pinch weld : 
keep in mind the subframe has the lower control arm mounting location and secondly If I dont move the engine ~4" down then I will have to remake the entire transmission tunnel and the Short shifter is gonna be almost at my shoulder, aaand the hood won't close.
Here is some more pictures to give everyone a better idea of the situation:
So if anyone has a better and less intrusive idea then me then fire away! Any help is appreciated.
I'm thinking that new/modified crossmember might be the correct way to do this.
buzzboy said:
I'm thinking that new/modified crossmember might be the correct way to do this.
Yup. But, if theres an oil pan that will require less cutting, get it.
When i ran into similar issues with crossmember and oil pan, i chose to modify both. Added a noch to the oil pan, and then thinned the proper section of the crossmember to clear the notched pan. Boxed the cut crossmember to add back the strength cut out.
Dry sump with a flat pan?
I mean there is nothing underneath a rotary engine that needs oil or would cause clearance issues. The pan is basically just storage, it could be relocated anywhere you wanted.
I'm in the modify-pan camp. Modifying the crossmember is a lot of work.
Dry sump is a great idea. You can also just get some sheet metal and notch the pan. I did that with a Caddy 500. Mine turned out OK, but I warped the rail a bunch.
The problem with pan modification is, I do not trust myself to be able to modify the pan, as I can weld big ol welds but im not super delicate and I just dont have any experience welding small thin metal. And Second oil pan option, dry sump is very expensive and I need to go down about 4 inches and a dry sump would only eliminate about a inch and a half.
New / Modified K member. Tack weld the frame together at the front and back behind the firewall and start cutting what is in the way. Get the motor in place and start welding the old one back together with some added steel. I would probably look at using new square tube steel and not actually reinstall install the old center section that you cut out.
Looking more at things if you drop the motor too far down you are you going to need a custom solution for the exhaust. It looks like the exhaust ports will end up being in line (or close to it) with the frame/K member and since you said that there are some suspension parts incorporated into the cross member you probably really don't want to get into mucking with the K member at the frame.
I would need better photos to see what is going on there.
the 2nd photo is what has me concerend about the exhaust if the motor was to come down say 2-3 inches
Having had the front suspenion on one of these apart, I would vote for modifying the crossmember extensively over modifying the pan. You're going to be adding extra power, and presumably corner loads onto a part that was designed and constructed using 1970s technology. Changing the crossmember is a one time job, changing the oil pan means that any future engine has to have the same modified oil pan on it, raising the stakes if something were to happen to it. It looks like you have some fresh brake and suspension bits that I assume you'd like to keep? Don't RX-7s run the crossmember in front of the motor? Using tactics from the Bad Obsession crew, I would removed the subframe, make a jig of the mounting holes, and then build a subframe that preserves the original pickup points but runs in front of the oil pan. With sufficent gusseting and modern design and steel I think you could get the strength of the original back easily.
Personally, I would also redesign the LCA pickups to use a more conventional double shear mount, the factory design did not strike me as being advantageous for strength, lightness, or serviceability. Actually, the whole suspension designed started bothering me more, and once I realized that I actually wanted to put entire Miata subframes under the the body it was all over; I sold the project and have ended up happily driving an NA Miata these days.
This is a good bit of info on 124 spider front suspensions. Note the bit at the bottom about subframe repairs... Depending on your goals, you may end up back in here modifying the subframe anyway.
Where are you located?
I'm familiar with weird swaps and rotarys...
In reply to MrRobogoat :
Alright update to everyone with some new information, I have a generally complete plan now and I'm looking for input, first: pictures so everyone has better context:
So, with some more accurate measurements I know now I have to come down almost exactly 3 inches and to do that I think I am going to chop the whole curved top half of the crossmember down to the pinchweld (if you can call it that I don't know, the flat part) and then rebox it in with some 3/16 steel box metal I have from the bottom. I am going to preserve the mounting to the body and the suspension by stopping right here:
And when I stay stop there its not gonna be a straight cut down I am going to tie it in at a slant and re-reinforce the top section where it mounts to the body. At this line the bottom boxing will also tie in at a slant with gussets ending right before the suspension mounting studs. This way I avoid messing up any suspension geometery, my exhaust headers can fit and the oil pan will fit.
The only problem with this, is it might not be enough. I did find this oil pan for the 13b: https://www.moroso.com/mazda20942/ with this oil pan I could easily bring it down more than 3 inches, but without it, its gonna be very close or not enough. The only problem with this oil pan is that the manufacturer specifically states it is not for FD or RENESIS 13B, I assume and hope that's just because the oil level switch and that can be worked around, but if not its back to the drawing board. I just put in an inquiry with the manufacturer so I will find out soon
So you guys think this is a good plan? This isn't my first rodeo, but it is my first engine swap so any advice is appreciated! And to answer wvumtnbkr's question: I am located in San Diego
bump, alright im doing it
I'm thinking it says non fd or renesis because of the engine mounts.
If you are not using the stock renesis engine mounts, it might work.
I'm thinking it says non fd or renesis because of the engine mounts.
If you are not using the stock renesis engine mounts, it might work.
In reply to wvumtnbkr :
yeah I asked them and they said it was because off crossmember Clearence in the cars, that is obviously not a problem here so I'm gettin it
