Moss Motors, Ltd

 I was waiting for Moss to assemble a supercharger kit for my 3-main '64 MGB.
 Moss says they haven't produced a supercharger for for the 3-main engine because it has a unique water pump which would be too expensive to adapt to a serpentine pulley for such a limited production. However it is possible to install the (150-058) SC for the '65-'67 mgb with the suppled pump (and the provided serpentine pulley) with some modifications. The down side is that the engine block would need some minor grinding at the pump opening to make room for the newer style pump but it would improve cooling.
 I chose not to modify the block. Instead, I had a water pump pulley turned at a machine shop to fit the original pump. The supplied pulley was welded to a billet aluminum fabrication.
 The Moss supercharger kit supplies a serpentine generator pulley that sits 1/4" farther out than the original. Therefore, the machined water pump pulley height was reduced by 1/4" to line up with the idlers and serpentine crank pulley correctly. The pulleys lined up pretty well so our new water pump pulley turned out to be a good fit.
 No real problems but admittedly no easy task getting this kit onto a 3 main MGB. My aftermarket header needed grinding at the head studs to clear the SC casting and there was some anxiety about the water pump pulley dimensions but it was all by the book after that. The new throttle cable has no provision to route securely behind the bonnet hinge so I used a lid switch harness clip (part#90016) from a Whirlpool direct drive washer. With minor alteration it clips the cable securely behind the hinge, preventing damage when the bonnet is raised.
 After everything was installed it started quickly needing only minor timing, mixture and idle adjustments. Next phase is to replace generator with an alternator.
 There's no reason why 3-main MGB's should be sidelined in this impressive upgrade. The extra effort was worthwhile.

 

Greg:

Thanks for the post. It's great to hear of people taking our base kits and making them work in alternate applications. The next time the Supercharger FAQ is updated, we will reference your suggestion.

cheers

 

 

---

Kelvin Dodd
Global Sourcing Engineer
Moss Motors, Ltd.
Helpful Links:
Code of Conduct
FAQs

Disclaimer: Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.

I have been converting my Moss blower to work with a 3-main MGB engine.

I started out with the blower mounted on the 1500cc B-series in my ZA Magnette. When that motor started getting a bit too tired I replaced it with a 3-main which is bored out to +.060, balanced, with an alloy 5-port head.

I went the other route and modified the block to take the later short water pump. This was very straightforward and took less than half an hour using a die grinder. I made up a simple 1/2" thick aluminum spacer for the water pump pulley. The alternator needed a bit of shimming as well.

I have done away with the distributor and fitted a Megajolt crank-fired ignition system which results in a very smooth running engine, although I do worry that I have made a simple car more complicated.

I am at the stage now of changing the carb needle to optimise the mixture. I have installed boost and AFR guages to help with this.

One question I would have is, What are the differences between the MGA and MGB blower kits? (Earlier version)  Are there any pulley differences or is it mainly in the carb needles and the water pump setup? Is a different carb piston spring used?

 

Cheers,

Rich  

Note: the water pump pulley was loose in this pic (not out of alignment!) this was a dry run to check crank sensor clearance.

---

Life is too short to go slow-Safety Fast!

Rich. As usual a really beautiful upgrade. I'd be interested in the parts you sourced to run the Mega Jolt system, as I'd like to play with a Megasquirt unit on a 1979 LE, I just bought that is fitted with the Moss Fuel Injection kit. The stand alone Moss control unit works fine, but it would be nice to be able to optimise spark and fuel rather than just be making the CARB people happy.

Once up to speed, I'd also like to do some work with cross flow heads, fuel injection and supercharging But that is probably going to be in another life.

In answer to your question. The dash pot spring in the MGA carburetor is green. The one in the MGB carburetor is red. The supercharger pully has the outer ridge machined off to clear the MGA support structure. Both the MGA and MGB have the same 2.75 OD pulley though.

The reduction in boost is done by using a bigger crank shaft pulley on the MGA kit. The MGB crank pulley is 052-097. Since you all ready have the motor assembled and the tooth wheel installed, I'd suggest running the engine the way it is, checking boost levels and your advance. The MGB motor will take more boost, so the easiest solution to get more power if you want it would be to change out the supercharger pulley to the MGB high boost one. 150-075.

Thanks for sharing. 

 

 

If you ever want to remove the water pump spacer and want the correct late MGB water pump pulley, the part number is 052-098 

---

Kelvin Dodd
Global Sourcing Engineer
Moss Motors, Ltd.
Helpful Links:
Code of Conduct
FAQs

Disclaimer: Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.

Duh. My Bad. The MGA crankshaft pulley is smaller than the MGB, not larger. That's what I get for answering questions without engaging the brain.

 The MGA pulley is 4.5" in diameter, the MGB one is 5.135".

Again. Though the easiest way to offset this is to use the MGB big boost supercharger pulley which is  2.60" in diameter.

 

 

 

---

Kelvin Dodd
Global Sourcing Engineer
Moss Motors, Ltd.
Helpful Links:
Code of Conduct
FAQs

Disclaimer: Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.

Thanks for the compliments Kelvin.

Thanks also for the information. As always you have the inside track on information!

The info on the pulley size probably explains why I was only getting 4lbs of boost on my old 1500. I was wondering if I was getting a correct reading as the increase in performance over the twin carbs was so dramatic. I have the boost guage and MAP sensor attached via the ports closest to the head. Is this the recommended place?

The new engine is approx 8.8:1 so I will try it with the MGA pulleys and see how it goes before increasing boost. I am not chasing a big HP number but just want good trouble-free performance.

The Megajolt installation was surprisingly simple. I cut down two 5/16" connector nuts to make the standoff for the sensor plate. One is attached where a timing cover bolt was located and the other bolts up to a motor mount bolt. It's very secure and vibration free. I don't know why other people have fabricated such elaborate mounts. The Megajolt wiring is very simple, and easy to make up. I have the EDIS and Megajolt located under the dash along with an auxiliary fuse box with the coil pack on the firewall below the battery tray. Have you given any thought to using fuel injection with a supercharger? It has crossed my mind, but this would have to be a future project.

I do have another parts questions for you. Would you be able to supply the Moss numbers for the red spring, and also for replacement damper plugs. I would like to have a couple of spare plugs on hand. I have already drilled mine out for the previous installation and it feels like I may have to open them up a couple more sizes for the new engine. (Update: now opened up to #39 but still have a gulp at WOT. I may wait until I change out the carb spring and needle before opening it up any more) As you know it is a lot harder to make holes smaller than larger so it would probably be prudent to have a spare set on hand for when the inevitable happens!.

Hey! Thanks again for mocking up the sample blower on your Magnette and getting me started on this project. It has been a ton o' fun!

Safety Faster!

Rich

The current engine bay

---

Life is too short to go slow-Safety Fast!