MG-TC and Shorrock supercharger

[DaveAhrendt]

I'm about to start on the installation of a Shorrock blower on my '46 MG-TC. The installation seem fairly
straightforward but I always expect the unexpected. Has anyone here done this install and have any tips, or
gotchas to pass along? I've heard about possible fan clearances.

Thanks,

[John Brownhill]

Hi,
I run 1946 TC 1350cc with a Shorrock
The problems I had was the radiator stay needed to miss the carburettor
so bend or make new, and the pulley fouled the radiator just below the header tank
only sheet metal so was cut away.The carb I use is a 1.1/2” SU with RC needle and red spring, I also needed to retard the ignition timing about 5deg pinking noted from low rpm.These settings are a good starting point I use a “A” oil metering pin but probably better with a “B” after rebuild. I also found after a run I had an oil build up in the carburettor, oil draining down to the bottom of the supercharger causing difficult starting after standing (mine is quite worn, rebuilding a replacement at present ) if you get this please let me know I have a solution. Lastly check your blow off valve because these are near the exhaust they suffer a bit, I had to replace mine, and have now fitted a s/steel heat reflector between the valve and the exhaust manifold.
John

[Steve Simmons]

A photo is worth 1000 words. The pulley does get close to the radiator and bonnet, but I haven't seen a need to cut them yet. Maybe John's engine was a bit high, or radiator a bit low?

[DaveAhrendt]

Thanks for the info guys. I bought a blow off valve relocation kit from the folks in UK and had a local shop tig weld the
bung in place. It comes out at a funny angle on the top of the manifold but it's not under and next to the hot exhaust.
Earlier I installed a CSI programmable distributor that has vacuum advance/retard. I plan to tee its signal line off the fitting from the manifold to the boost gauge.

So far I have the bonnet off, radiator out and the crank pulley out. Ready to speedi-sleeve the new pulley. Looking at the new pulley I should have realized that I'm going to need to lift the engine to get the pully installed so off with front motor mounts.

[Duncan M]

Curious what you will be changing the ignition advance to. All in by 2,500 rpm? Or?(●'◡'●)

[DaveAhrendt]

Duncan,

I'm not too sure yet. I've been doing some reading about timing under boost but haven't settled on anything.
I'll probably keep the MAP sensor disconnected at first. Do you have any suggestions?

Steve,

Do you recall how your timing is set? Looking at your picture do you have a secondary fuel pump plumbed in?
Another question. How much oil do you keep in the front extension? The instruction sheet from Shorrock is pretty confusing.
"The drive housing is now partially filled with good grade 30 weight.......via the plug on top, the level being governed by the plug on the underside of the housing". Not sure what they mean by that.

[Duncan M]

Dave-
No advice on the timing advance changes. Just curious.

[DaveAhrendt]

Anyone know whether a radiator fan spacer was used with the Shorrock? I finally got the new crank pulley installed and noticed that the front supercharger belt will foul the fan blades. I was thinking about getting a TD spacer and cutting it down as required.

[Duncan M]

Of course you could also just eliminate the standard fan and install an electric fan to suck air in- for around town. Up against the back of the radiator. Some prefer a simple on/off switch to a thermostatically controlled setup.

[Steve Simmons]

My Shorrock is in shambles so I don't have any personal experience running one on my own car. The car pictured is just one I inspected recently. I believe it does have a spacer but it's hard to see for sure int he photos. There's something silver behind the fan so probably an aluminum spacer.