Tim Suddard
Tim Suddard Publisher
6/29/18 8:55 p.m.

While often lamented, Triumph’s 1500cc, four-cylinder engine is still owned and loved by thousands of enthusiasts. Almost 100,000 of these engines were used in the 1973-’80 Spitfires, and nearly as many were used in MG Midgets sold from 1975 and later.

Right off the bat, this larger engine delivere…

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TR8owner
TR8owner HalfDork
7/1/18 4:24 p.m.

I was always much more partial to the 1296cc Spitfire engine than the 1500. Maybe because its the one I raced back in the day, but it always just seemed better balanced than the 1500 for some reason. As for the MG Midget, I preferred the 1275. Had one on the street will all the competition Cooper S parts. It went like stink. Always seemed like a sacrilege putting a Spitfire engine into a Midget.

clshore
clshore New Reader
7/13/18 8:59 a.m.

In reply to TR8owner :

The 1300 Spitfire and MG motors shared quite a lot; iron block, 3 main bearing crankshaft, similar bore & stroke, similar cylinder heads, similar carbs, similar power.

But the US emissions regs sucked away both torque and power. A larger motor was needed.

The MG motor was incapable of being enlarged, just getting it to 1275 had required engineering handsprings (offset conrods? Really?).

But the Spitfire could be easily stroked to 1493 cc to regain some performance.

Given that MG and Triumph were both owned and built by BLMC, choosing the Spitfire motor for both was a no brainer. At least the MG stayed 'all British'.

79Midget
79Midget
3/25/20 1:49 p.m.

I did the SU conversion source from Quantum Mechanics along with a 5 speed transmission also sourced from Quantum.  It has transformed the Midget into a nice little cruiser.  I tried the Weber DGV for a while but the SU's are more responsive plus I get better gas mileage ( the 5 speed helps).   I replaced the original exhaust header with a Pacesetter which increased the pipe diameter to about 2" but have learned there are better ones available.  I was not aware of the header from the UK.  I also experienced the thrust washer failure which ruined the crank so my advice is to keep your foot off the clutch as much as possible.  All in all, even though there are more desirable sports cars out there the 1500 Midget has been a fun car to have owned for the past 18 years.

murphmi
murphmi New Reader
9/1/21 9:28 p.m.

I remember reading a brief article in Road & Track back in the 70s that with the two SU setup, there's a problem that at higher RPM the mechanical fuel pump doesn't deliver enough gas, causing fuel starvation. The solution is an electric fuel pump in the trunk, and bypass the mechanical pump. But not just any pump--SU carb float valves will allow gas by if it's under too much pressure, so you need a low-pressure pump or pressure restrictor in the system. 

The problem with the thrust bearing is serious, and every Spitfire (or GT-6, or TR-6) owner should know how to check crank end play. I know I was able to replace the thrust bearing in my TR-6 by dropping the pan and removing the rear main bearing cap, but can't remember if it the same on the Spitfire. A fair amount of work, but nothing too technical, and it saves the engine. And oversized washers are available if there's wear on the crankshaft. And it's easier/cheaper than replacing the crank and rebuilding the engine!

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