Moss Motors, Ltd

Hi,

 

I have recently purchased at 1972 MGB GT. It came with a Moss Supercharger that was installed 3 years (25,000 miles) ago.

The problem is that it has a loud rattling noise. Does anyone have any ideas.

Thanks in advance,  Steve 

.  

 

Using a piece of hose as a stethoscope, can you isolate the noise? Is it in the blower or in the engine?

Thanks for your response.

 The rattling/grating sound is coming from inside the supercharger where the fins are.
When the revs increase...the noise also increases. I have been in contact with Moss Motors Tech Services department..they say that it might be a bearing. It may well be a worn bearing that is causing whatever it is attached to hit the inside of the casing.

I really don't know how its constructed, so I'm really guessing.  I will be glad of any information you can offer.

 

regards,  Steve

Me again,

 

I have just checked the oil level through the hex nut at the front of the supercharger. There is only approx one inch

of oil in there....could this be part of the problem?

Thanks,  Steve

Steve.

Rattling from the inside of the housing does normally indicate a bearing failure. If caught early on, the rotor group will not be damaged and the unit will just need to have new bearings fitted. All of the Moss and Jackson Racing superchargers are serviced by Magnuson Products who supply support for the Eaton aftermarket supercharger program.  www.magnusonproducts.com

They also have some very good information about the various units. The MGB kit uses the M45 supercharger, as do all of the earlier Mazda Miata kits. The new MGB kits use the internal bypass MP45 supercharger.

Moss does handle supercharger repairs through Magnuson, contact Keith Taber X 3019 who is the Moss supercharger technical specialist for a return authorization and further details. He checks incoming units to make sure that the problem is internal, then shepherds the repair through Magnuson's system and will contact you with an estimated repair cost. If the rotor group is undamaged, the cost to bring the unit back to top condition is not very great.

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Kelvin Dodd
Global Sourcing Engineer
Moss Motors, Ltd.
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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.

Hi Kelvin,

 

Great information. Many thanks for taking the time to respond to  me. I will go on the Magnuson website and contact Keith Taber soon.

As the supercharger has only 25,000 miles (or less) on it since installation in March of 2006, I am surprised that it would need repair at this point. As previously mentioned, there was only about one inch of oil in it when I checked yesterday. I was thinking that it should be up to the level of the fill hole in the front? Can you also advise what kind of oil is best for it. 

I will let you know how it all turns out. 

 

regards,  Steve Wareing

Hello,

I replaced the two roller bearings in the rear of the superchargers as well as the coupler. This has elimated the rattling.

My only difficulty is that fluid leaks from the nose section. Should it have a gasket? (it didn't have one when I pulled it apart)

 

thanks again,  Steve

 

Steve.

Glad you got the rattling taken care of.  

Watch out for the fluid level. The oil should ABSOLUTELY NOT be level with the fill plug!!!!  Here is the correct technical information:

Moss Motors Supercharger Oil Level and Oil Type. . . . . . . . . .

The Eaton M45 supercharger in Moss Motors MGA/MGB Supercharger kits contains 100ml of specially formulated supercharger oil in the gear drive cavity. The cavity fill plug is torque-sealed by the manufacturer. This should not be tampered with. Any service to a supercharger should ONLY be done by the manufacturer or the Moss warranty will be null & void.

100ml of gear oil is approximately 1" (or slightly less) of standing oil at the bottom of the gear drive reservoir. A pipe cleaner (or similar devise) can be used as a measuring tool and inserted as to touch the bottom of the reservoir cavity. Approximately 1" of the tip of the pipe cleaner should be covered in oil. The oil fill hole on the front cover is NOT a fill-level-indicator nor should ANY supercharger oil be added before completely draining the original oil.

Remember - removal of the oil fill plug will break the torque seal and void the standing manufacturers warranty.

The specially-formulated supercharger oil is picked up by the drive gears and is 'atomized' providing an oil residue on all wearing surfaces. The design of the drive gear system is such that oil from the drive system cannot enter the rotor chamber unless the rotorgroup bearing plate has been fractured or compromised somhow or the bearing seals on the drive cavity-end of the rotorgroup fail. Each thing is highly improbable. Bearing seals last typically for 100,000 + miles.

Oil residue inside the intake tract will typically be from the crank case ventilation system, which should be checked thoroughly for blockage. The oil IS NOT from the rotorgroup drive. If oil is found in the intake then the crank case ventilation screen in the front valve tappet cover should be checked and either cleaned or replaced.

---

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.

Thank you for your response Kelvin,

So, it appears that I have been adding too much Supercharger fluid, Filling it to the level of the the fill plug is probably the reason that it is leaking...I will remove some.

As the Supercharger was fitted in the UK some 3 years ago, I am sure that it will not be covered by a warranty. Other than the leak, it seems to be performing well.

Thanks again,  Steve