I don't want to further hijack another thread, so I want to make a little reference for those looking to fit new motors into old cars. I'm putting a bastardized 13B (12A plates with GSL-SE rotors, e-shaft, and housings) into my RX-2, but I know that there are lots of options when fitting a newer motor to an old RX.

Let's get a thread going to discuss: Engine Mount Options, CAS / S3 Distributor ignition upgrades, Oil pan and pickup conversions, radiator fitments for newer cars, electric fans, etc. as it relates to getting a new motor in an old car. I think there's enough support elsewhere that we don't need to water it down with carb and EFI advice, but I'm sure that there are other concerns that we could use a single reference.

Discuss. And lets see if we can get a nice handy reference together.

 

I picked up a GSL-SE oil pan to replace the one that came off my motor that is all hacked up. I'm also adding an oil pan baffle that's easy to make at home with a drill, hole saw, and some sheet metal. I'll post the print that I made up later. My real question is about the oil pan.

I was told many moons ago that an RX-2 or RX-3 13B needed an oil pan only sourced from the old 13Bs pulled from RX-4s, 5s, and REPUs. They had to be modified, though, because those old 13Bs had front sumps, but the RX-2 and 3 needed a rear sump. Previously, since the sump was on the wrong end you had to cut the flange from the pan, spin it 180, and weld it back on (mine had been siliconed back together, so I want to find a new pan for my swapped motor). The alternative was that you could lay an oil pan gasket onto your flange, spin it 180, and redrill the holes along the front and rear edges so that the pan would now bolt up backwards. I was told that the GSL-SE fixed all this when it was introduced, because it was the only front-cover-mounted, rear sumped 13B pan Mazda ever made. THIS INFO WAS WRONG and I helped perpetuate the myth because I didn't know any better. The -SE oil pan is just like any other 12A pan, with the sump in the front. You'll need to spin your pan around, as there is NO bolt-on fix. That said, here are a few tips.

1.) Get a S4-S5 RX-7 oil pickup. They run back and to the center. In order to clear the crossmemeber, the sump needs to be moved to the back, so you'll need a longer pickup. The 2nd Gen pickup can be straightened a bit and get way back there and does a nice job.

2.) Modify your oil pan. I'll redrill mine and use little reinforcement bars that spread the load along the flange of the pan. This way, when you have a bunch of unused holes you're not going to warp the pan and develop a leak. Check the pictures to see what I mean. I'll make up and post a print to show what you need in order to recreate my load-spreaders.

3.) Oil level sender blockoff. Most of us no longer use all the stock bells and whistles, and I've simplified my harness to no longer use the low oil level sensor in the pan. As long as I've got oil pressure and no leaks, I'm not worried, and the blockoff plate is pretty simple. I'll post a print for that as well, in PDF format.

4.) Oil Pan Baffle. A good idea, but by no means necessary. It basically goes between the pan and block, and will need an extra oil pan gasket, if you're not just using sealant. This keep the oil from running up one side of the pan and away from the sump under hard cornering. It's just a piece of sheet with the oil pan hole pattern along the edges, and thru-holes for the oil pickup, dipstick, and a couple smaller holes to allow oil to return to the pan. None of the holes are very close to the edge, so it'll keep more oil down in the sump in the twisties.

Personally, I'm kinda excited about the load spreaders for the oil pan. Someone made up a nice set when they cobbled my engine together, but I've never seen them available anywhere else. It wasn't my idea, but I'll gladly make up some plans so that others may copy them. The best way to go is if someone with access to a waterjet could cut a dozen sets from 1/8 sheet and let the rest of us know that they're out there. PM me if you might be able to do this, because it would mean an easy transition to a new motor and much less risk of deforming the flange, now that it's been weakened. Besides, these pans are typically available only from junked 84-85 GSL-SE's, so they might get kinda scarce.

 

What I did to fit my S5 T2 motor in my duce.

* 12a Front cover, stock engine mount brace with new motor mounts.
* GSL-SE oil pan, reversed and redrilled.
* I used the stock 12A twin dizzy motor oil pick tube, and just bent it down a bit with a rubber mallet.
* Custom Exhuast manifold from www.rx3mist.com
* Spacer for transmission mount. Spaced it back about 2", used steel plates from home depot.


Thats all I can think of off the top of my head, I went with e6k EMS.

 

Are you running the stock RX-2 radiator and oil cooler, then?

 

Your pick up tube has a crimp and the lenght before it drops to the pan looks kinda short. With the ones I've done, we just cut it , weld a piece of pipe with same diameter, and then re-weld the other end where the 90* bend is.

For the oil pan, yes, you have to drill new holes on front and rear And at the same time, re-shape a few stock holes (ova). I have been using dremel but lately, the rotozipper.

For tranny mount, as trainwreck said, flat bar or angle bar or anything strong enough. You may need to enlarge the tranny tunnel to fit other than stock tranny.

 

The pickup shown is the one off my block, which I can't trace the origin of. Today I picked up an oil pickup from a 2nd gen, and it's a bit longer and more direct.

 

I used FB 3 core short radiator.. been holding temps down fine on my little beast.

I used the stock oil cooler and orginal oil cooler lines.. I know I should get the lines remade.. but they seem to be doing fine and in pretty good condition. Have no issues with oil temps.

 

In my RX-3 wagon, I used to have an 79 RX-7 radiator, the holes were different so I had to use flat washer to hold the radiator in place, now I have a radiator out of a RX-2, had to oval out the holes a little to get a good fit. I am running a push fan in front since I have no space literally between radiator and motor. I ran a piece of thick aluminum plating as a spacer for the tranny mount. It has been holding good. Make sure you get the correct sending unit to match your vehicle. 79 and newer sending units will not give a correct reading in our old school rides.

 

I personally dont trust any of those aging gauges. Hook it up for looks BUT install a mechanical oil pressure and especially water temp gauge for accurate reading.

 

I have the same pickup for my engine. I believe it is from an RX 4

 

13btt in duece.Ill try to get picture here in the next month but its hard going between here and oregon to work on the sucker. My install was a little more of a head ache, I wanted to move the motor back as to make room in front of the motor for radiator fans and intercooler. I ripped out the old steering moved the motor back to the firewall made a new mount across the back of the engine bay from frame to frame using the 13btt stock mounts. For the original front cross member( this is difficult to explain ) we cut it down so that top part that bubble around is no longer there and its a flat piece with a plate coming off of it and it has the modified FD rack and pinion mounted to it. Next time i go up there ill have my digitall camera and ill take a bunch of pictures. Good thing is it looks like I can fit a 3rotor now.

 

In a RX-2, 79/80 RX-7 12A trannies bolt right up to a later model 12A with no cutting required (maybe some banging), correct? 81+ trannies have the shifter a few inches back, and require shortening so they don't run into the parking brake?

Sorry, I used to know all this stuff ages ago but it's faded.. just wanted a refresher for a friend who's going to be doing one of these swaps on a stock auto RX-2.

Mike

 

Hey Crit,
Moroso also offers another option for 13b oil pans and RX3's, part#No. 20942. It looks real nice too! Unfortunatley, they don't mention the RX2 in their description.

 

That would be me. I am completely new to everything Mazda much less rotary, being a Euro type of guy myself (Alfa 164Q, Saab SPG, Merkur XR4Ti will be the RX-2's stablemates - plus the Suburban ) and there seems to be very little information in one place on the 'net - just a lot of little pieces.

What I've got is a bone-stock 1972 RX-2 with 37,000 miles, an automatic transmission, and a near-complete ignition failure. I am not going to put time or money into making that old ignition system go, so what I'm trying to assemble are my options.

I have in my possession is a good FB 12A and a dead FB 5-speed. I have no idea what year they're from. I think '82 or '83, but who knows?

Can someone please oh please just tell me what parts I need to assemble and what parts I need to buy and what parts I need to fabricate to put that FB 12A and some 5-speed OR automatic in my RX-2? I'd be immediately interested in going automatic for no other reason than a minimum time to roadworthyness before tackling a 5-speed swap. I get the distinct impression clutch-related parts will be a holdup.

Anyway, I have access to a shop, a lift, tons of tools, and the best junkyards in the world... If I know what I'm looking for I can find them and install them.

 

Those oil pan 'load spreaders' are actually stock on all engines from '78 and before. The bolts are, of course longer, and have an added lock washer.

Notice the slightly rusted part on one in your picture? That pattern is from an earlier pan with a raised gasket sealing surface. Mazda went to a flat gasket surface around '78 or '79.

I've been able to avoid leaks in both early and later (flat gasket surface) pans without need of the 'load speaders' by applying RTV to both sides of an oil pan gasket and torquing evenly to at least 7 foot pounds (factory spec on 6mm x 1.00 bolts).

You've gotta use the later style short pan bolts if not using the load spreaders. My friend had a jumbled mix of pan bolts and broke one of the long ones off in his engine because he wasn't using load spreaders. He had to drill and tap for the next size up (8mm x 1.25, commonly found at the top of rotor housings, intake manifold to engine etc).

 

I think this is the pan you are talking about.

I have done so much to my RX-3 to put a REW into it it would take me all day to describe it all. But if you have any questions just shoot me a PM.

Allen

 

I used the moroso #20940 rear sump in my rx2 when I installed my 13b. I took my front motor mount cross member and had a welder cut the middle to make more room for the deeper pan and then just dippled the back just a little to make the steering turn competely. Sounds like alot but is really simple and I now have 6.5 quarts of oil(cooling) and oil always is there even on launching.

 

Did the moroso rear sump come with a new pickup?

THESAMEGUY - Are you looking to just fix the ignition failure? If so, you can put a jack under your oil pan to supoort the motor. You can then unbolt the front engine mount and remove the water pump and twin-dizzy front cover. Any junkyard 12A cover from a 83-85 (pref. 84-85) RX-7 will bolt on to replace your twin-dizzy cover. You'll then have a single distrubutor, parts support from Autozone, and electronic ignition. There are two ignitors on the new distributor that will fire your coils, so those are the only changes you'd need to make.

If you go the junkyard route, pillage any other 7's for their ignitors and grab a pair of coils if yours are fairly old.

 

Is this a "I think" or an "I know" comment? I have read a couple pages online which seemed to indicate this is possible, but talked to other folks who say it isn't... And, of course, other people who weren't sure.

I have a single distributor 12A in the garage but I don't know what year it's from. Are all FB 12As single distributor and there is some specific reason why it's gotta be '83-'85, or are only '83-'85 FBs single distributor? The reason I ask this question is that I found (and took) a distributor from a junkyard FB RX7 a few weeks ago, but it was labelled an '82...

The 12A I've got is absolutely ready to be dismantled at the drop of a hat. If this actually works, I'm all for it! During reassembly, are there any gaskets that are needed? Sorry for such a lame question, but I'll need to get any parts for this swap in advance, rather than by the discovery method.... I'll replace the water pump at the same time... already have new plugs, cap, and rotor...

Thanks *so* much...

 

83 and up had electronic ignition on the single dizzy, and 84-85 use a cleaner installation with the ignitors mounted to the side of the dizzy rather than in a separate box, like earlier units.

 

I have a 1985 12a and a 1979 1st gen transmission in my Rx-2.
Twin dizzy oil pan and pickup were used.
I have used the standard two-piece driveshaft.
This combination puts the engine about 2 inch to the front so I removed the rubber mouting blocks for the radiator to make the 85 thermo fan fit.
I did not have to modify the transmission tunnel at all but I used the smaller FC NA starter motor.
I was lucky to find an engine crossmember from a single dizzy Rx-2 so I only needed to fabricate the engine bracket. I believe the x-member I have now is the same as the Rx-3 engine crossmember.
I have used the 85 ignition system and replaced the coils too with the electronic ones.

I will try to post some pictures later.

 

this. . . im very interested in. . . as its what i was wanting to do to my deuce sedan. id like to see pics and even a more detailed description.

 

Crit - the pickup came with the pan. Look up #20940 on moroso web site.

 

What's the deal with swapping front covers? Can a 12A front cover be used on a 13B?

 

I have a 12A cover om my 13B-REW. You just don't use one of the bolts in the cover.