On 6/10/2018, Thomas (duc1) wrote:

"One problem on my MGA needed a lot of time and a little bit of engineering work until I was able to solve it finally - overheating. I've done all the stuff found on your site and on the internet:

Ignition setting Carb setting Flushing the cooling System Felt under the bonnet Different types of water pumps Grille modification Thermostat Blanking sleeve

Nothing really works!
So I started to do some work on the water pump and found out that most of the aftermarket pumps are more a 'mixer'� than a pump (I'm sure the original one will be the better/best choice). Based on that most of the time my MGA was running with a thermosiphon cooling system only. Really poor supported by the water pump.

I decided to design my own water pump impeller and replaced the impeller of an original looking iron casting pump with this. Looks great - works perfect! No more overheating issues up to really hot days (>30°C) during hill climbing or highway use.

Find attached some pictures. Maybe this also helps others to cool down there MGAs".

On 6/24/2018, Thomas wrote:
"The iron cast water pump is an after market one. Not sure about the manufacturer of this pump is because I ordered this pump from a MG spare part dealer. Important in this case is that it has an iron cast housing. Both types of impellers are not closed on the end so all of them recirculating the water by a hydraulic 'short circuit'. On the water pump on the picture I've replaced the original 4 blade impeller (on the right) with my 7 blade one (on the left side, cast and machined). The 3D CAD design work and some CFD flow analyses was done by myself. Also I've machined the outer diameter and the blade angle to get the right gap between the impeller and the housing. The original impeller of this pump was machined in the bore only and has had a really big clearance between impeller blades and housing. If someone needs more support or is interested in some impeller castings please feel free to forward my mail address": duc1@freenet.de

Addendum June 7, 2020::
At 04:55 AM 6/7/2020, Thomas Gall at GALL MECHANICS wrote:
"The feedback has more than surprised me, I still get regular inquiries about my impeller or my pump. After the article was also published in some MG Club magazines, I decided to produce and sell this pump in my own small series due to the high demand".

The following MG water pumps are now available:

Impeller diameter 2 3/8" (60.3mm) Pump GWP103: - MGA 1500, 1600, 1622 (not Twin Cam), 1955-62 - Magnet MG Magnette ZA ZB, 1954-58 - Magnet MG Magnette Mk3, Mk4, 1959-62 MGA Twin Cam impellor Impeller only for Pump AEH461/2: - MGA Twin Cam), 1958-60 Pump GWP115 (on request): - MGB, engine 18G / 18GA, 1962-64 Impeller diameter 2 13/16" (71.4mm) Pump GWP114 (on request): - MGB, engine 18GB / 18GG, 1965-71 Pump GWP130: - MGB, engine 18V, 1971-80 Thomas Gall Hauptstrasse 68 73275 Ohmden Germany Mobil: +049 177 5119059 Mail: gall_mechanics@gmx.de Addendem: On 30 January 2022, Thomas Gall at GALL MECHANICS added: Prewar TripleM - Impeller "RACE" or "STR--STREET" PA/PB/NA/NB/L/K pumps, plug ‘n‘ race - no changes to the pump required! Coming soon XPAG MGC