Bridgeport 12A in an MG Midget
11-22-02, 02:26 PM
#26
Hmm. A bridgeport needs an open free flowing exhuast to perform decently. Pretty much anything from Racing Beat should perform well enough I'd think.
The exhaust on my MG is very loud. It has a very short primary header and a 22" long glasspack from Rotary Performance (they're out of bussiness) and a dual Monza tip tail pipe. Here's a pic:
The exhaust on my MG is very loud. It has a very short primary header and a 22" long glasspack from Rotary Performance (they're out of bussiness) and a dual Monza tip tail pipe. Here's a pic:
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11-23-02, 01:26 PM
#29
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Originally posted by Jeff20B
In the old days of peripheral porting, people would simply tap and plug the tension bolt hole in the upper corner of the rear plate to keep coolant from seeping out. From my test fitting of a '73 rotor housing to a '74-'78 rear plate, I think only two tension bolts need to be tapped and plugged. They're the ones right by the Leading plug and the exhaust port (these were relocated slightly in '74 for better spark plug location and a different exhaust port shape). However, there may be one more in the upper corner that'll need to be plugged as well. This is probably the same as the one that gets plugged !
In the old days of peripheral porting, people would simply tap and plug the tension bolt hole in the upper corner of the rear plate to keep coolant from seeping out. From my test fitting of a '73 rotor housing to a '74-'78 rear plate, I think only two tension bolts need to be tapped and plugged. They're the ones right by the Leading plug and the exhaust port (these were relocated slightly in '74 for better spark plug location and a different exhaust port shape). However, there may be one more in the upper corner that'll need to be plugged as well. This is probably the same as the one that gets plugged !
CJG
11-24-02, 03:46 PM
#32
I was going to do what Racing Beat did when using older end plates with peripheral rotor housings. I'll simply tap some threads in the end plate's offending tension bolt hole and plug it with a bolt. The loss of just one tension bolt doesn't seem to cause any probs with a high output PP engine. Infact, '76 engines had an undrilled casting there. The nitrided FB plates don't even have a casting there (and are missing two tension bolts compared to '73 and '74-75). Those FB engines can be turbocharged without a failure caused by missing tension bolts.
Granted, the two tension bolts I'm going to be removing are in the lower half of the engine, where the most stress is, but the engine will never be stressed from a turbo, or experience the high RPMs of peripheral porting. That's why I am only interested in bridgeporting or streetporting. Infact, the way things are going, I may only streetport since there is so little room in the engine bay of a Midget. I guess I could do what RX-Midget did and mod the foot box so I could run some sort of Weber carb, which would lend itself to a bridgey really well, but the car needs to let me know what it wants, so to speak.
So anyway, I'll be using all '73 housings except for the end plate. Drilling the holes out isn't much of an option, or is it? I'll think about it.
Granted, the two tension bolts I'm going to be removing are in the lower half of the engine, where the most stress is, but the engine will never be stressed from a turbo, or experience the high RPMs of peripheral porting. That's why I am only interested in bridgeporting or streetporting. Infact, the way things are going, I may only streetport since there is so little room in the engine bay of a Midget. I guess I could do what RX-Midget did and mod the foot box so I could run some sort of Weber carb, which would lend itself to a bridgey really well, but the car needs to let me know what it wants, so to speak.
So anyway, I'll be using all '73 housings except for the end plate. Drilling the holes out isn't much of an option, or is it? I'll think about it.
01-20-03, 03:08 PM
#33
In the process of spring cleaning my garage, I tried two 12A oil pans ('73, '83-85) and neither one fit the MG. 
Long story short, it looks like I'll have to go back to a 13B in the Midget. I was planning on puting the 13B in my baja because of its great low end torque, but everything about this engine fits so well in the Midget that I won't have any fitment issues like I'd have with a 12A. The oil pan drain plug clears the cutout in the frame rail, the intake manifold doesn't touch the unibody or upper foot box area, the exhaust header also fits fine, the oil pressure guage fitting is the correct thread pitch and length, the heater core fitting can be easily blocked (there's no heater core), the temp guage sender works, etc. Even the choke on the carb works and it has a great idle when cold.
I'll try to keep this thread updated with my project.
Long story short, it looks like I'll have to go back to a 13B in the Midget. I was planning on puting the 13B in my baja because of its great low end torque, but everything about this engine fits so well in the Midget that I won't have any fitment issues like I'd have with a 12A. The oil pan drain plug clears the cutout in the frame rail, the intake manifold doesn't touch the unibody or upper foot box area, the exhaust header also fits fine, the oil pressure guage fitting is the correct thread pitch and length, the heater core fitting can be easily blocked (there's no heater core), the temp guage sender works, etc. Even the choke on the carb works and it has a great idle when cold.I'll try to keep this thread updated with my project.
01-25-03, 01:31 AM
#34
Here's an update. I've located a 13B that comes very close to the 13B that was in the MG last year. The oil pan will have to be swapped, the oil pressure fitting will have to be redone, and it'll need a flywheel and pilot bearing/seal, but everything else will fit; even the intake manifold. The only thing I'm not sure about is the heater core outlet pipe. I think I can simply block it like I did on my other 13B, but we'll see.
02-08-03, 10:36 AM
#36
I thank you for your concern, but I was diluting myself into thinking I could get away with it in my MG without redoing the exhaust. And now the oil pan issue...
Ok, here is what I'm doing with this car: I'm for sure installing a stock ported '76 13B with a RB light steel flywheel as this engine is coming out of my automatic Cosmo (cosmo's getting a newer jspec engine). The light flywheel will prevent at least some of the burnouts I was experiencing with my REPU's engine and its stock heavy flywheel (which was installed last year, as mentioned above). No wonder the 1000hp Supra guys went with lighter flywheels in order to prevent burnouts and decrease their times. There's no point doing a bridgeport in this car untill I can do it all the way. That 13B ought to have enough power for me at first anyway.
Ok, here is what I'm doing with this car: I'm for sure installing a stock ported '76 13B with a RB light steel flywheel as this engine is coming out of my automatic Cosmo (cosmo's getting a newer jspec engine). The light flywheel will prevent at least some of the burnouts I was experiencing with my REPU's engine and its stock heavy flywheel (which was installed last year, as mentioned above). No wonder the 1000hp Supra guys went with lighter flywheels in order to prevent burnouts and decrease their times. There's no point doing a bridgeport in this car untill I can do it all the way. That 13B ought to have enough power for me at first anyway.
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