From: Lorne M. Goldman
"Have any of you heard
of a turbo-charger for the Triumph engined Morgans?"
SHEALLY WILLBURN WORRALL MACDONALD
Dear Lorne,
As to the Turbo/blower/super charger units for a TR4. Paxton, Judson and Rootes come to mind and have been used in the past.The principle was the sliding vane type blower system.
N.B. They should only be used in the TR4 when you are not going to turn high RPMS with the engine for it has always had a heavy crank supported by only three main bearings. In the best of conditions , with a balanced engine, rods, crank and flywheel pressure plate, the engines have never liked high RPMs
The TR4 delivers great torque if one uses his head and not his foot and chooses a blower as mentioned. You would have a very nice unit. I used to race TR4s and had the pleasure of owning and racing Group 44s last solid axle car the 65 National winner. I stayed with SU carbs and later 45DCOE Webers and never a blower because of the rules at the time. I was always pleased with my engines running them at 14.5 comp ratio,steel head gasket F,D,and G3 cams and some additional grinds,overdrive in all four gears,various overbores and RPMS at 65 to 7500 but always with a eye on balance and the bottom end got rod and main bearings quite often to make the bottom end live under those conditions. The point is the TR4 is a good strong bottom end torque engine that 5500 and under RPMS lives well but when asked to turn over 55 has to be maintained on a regular basis with change of rod and main bearngs to keep the crank alive. Bearings cost much less than engine rebuilds. Make sure your TR4 is balanced and blueprinted where possible. Be warned if you find on of the mentioned blowers usually some adapting and machine work is required for fit and by all means top it off with a rev limiter. I prefer the MSD with soft touch. and remember the saying of the drag racers (Injection is nice but I would rather have the engine "blown").
Best to you,
JHSII
Hi Loren,
I've not heard of a TURBO charger for the Triumph engine. I suspect that, as the Triumph engine was long out of production before Turbos became popular, no one bothered to build a Triumph turbocharger. The only supercharger that I know of for the Triumph is the Judson, though Shorrock might have built one as well. (Shorrock superchargers are still available. Webmaster note.)
All the best,
Gerry
Turbocharging is somewhat modern technology to use on an old engine but they (the Triumphs) have been successfully supercharged! It takes a lot of space and necessitates bonnet bulges and other body mods.
The last supercharged Plus 4 I know about was done by John MacDonald of I & J MacDonald, Morgan Agents in County Durham, UK. Emai; INFO@macracing.freeserve.co.uk
Hope this helps,
JOHN WORRALL
We have used two types of supercharger on the Triumph engined Plus Four.
1) Shorrocks C142B vane type with 1.3/4" S.U. carburetter.
This was for road use and gave the car equivalent accelleration to a 1976 alluminium bodied 3.5 litre +8 (we raced them up to 120mph side by side). The main problem was vibration from the supercharger causing fuel frothing in the carb. float chamber. This was cured with a highly flexible connection between the carburetter and supercharger and a steady bar to the carburetter.
This set-up was designed for continental travel with best fuel consumption. the carburetter limited the available power but the combination gave very good low and mid-range power.
2) Wade RO20 Rootes type.
This set-up was used with a 2" S.U. carburetter or, for racing, a twin-choke Weber. Two speeds were used 0.8:1 and 1:1 depending on the power required. We normally used a specially ground camshaft which gave limited overlap but higher lift. Compression, from memory, was about 8.0:1 with 1:1 drive.
Under severe conditions the cooling system had to be in good order and we used a big oil cooler for racing.
This work was carried out some years ago but I think I still have the templates for the supercharger mountings and possibly an RO20 supercharger with the adaptor for the Weber twin-choke carburetter. A hunt through the records might produce some dyno figures but I suspect these may have been discarded.
If I can help further please let me know.
John MacDonald