Oil Pump

[jddevel]

Whilst stripping and cleaning the oil pump on my TC- so the early type with separate filter, I noticed that the oil groove inside at one end of the distribution cylinder is blocked off with what appears to be solder. I did not notice on dismantling which end the "blockage " was so need the following questions answered please. Which end should the blockage be- nearest the engine block or the cap. My belief is the cap end, Plus the blockages' purpose. My assumption is to force the groove to supply the necessary lubrication to the shaft.

[jddevel]

Apparently this is not normal and it`s been suggested by Steve Baker that it may be a piece of bearing white metal that found its way into the grove.

[Steve Simmons]

It doesn't sound right to me. Someone could have been modifying it for whatever reason. If it was white metal, it wouldn't be melted in place though!

[jddevel]

Yes Steve. The curiosity of the MG cars. Have decided to rebuild the pump with new drive shaft and gearing, otherwise everything else seems "tight"

[jddevel]

One further point when discussing the subject with a machine shop was that wear can take place on the inner surfaces of the cast body that the gearing spins in thus reducing pressure. Anyone any idea what the original measurement between the ends of the teeth and the walls of the body may have been? I suspect a couple of thousands.

[Tom Lange, MGT Repair]

An excellent discussion of checking and rebuilding an oil pump is the information sheet supplied by Moss Motors with their kit. It is also readable by going to their on-line catalog, and clicking the icon by the oil pump kit - they give all the necessary specs to check.

Tom Lange
MGT Repair

[Steve Simmons]

I'm not sure where you're located, but Butch Taras in California does the best rebuilds. The clearances are all set properly, the correct circlip is used, and the lid is surface ground for flatness.

[Tom Lange, MGT Repair]

Steve - he's in Cornwall, UK. A bit far, I agree, but worth it for the best rebuild!

Tom Lange

[Ray White]

You could try Roger Furneaux - not that far from you. He machined my TC oil pump gears to fit.
Also... reasonable prices.!

[jddevel]

Thanks Ray. He did my axle.

[ROGER FURNEAUX]

The Moss instructions make no special mention of the all-important circlip at the top of the shaft, but they and NTG show a modern one. Perhaps TL or somebody could remind us of the current thinking on this subject, i.e. are they too thin and liable to fail? Whilst I can get the machining done here in Devon/Cornwall, I don't rebuild the pumps, but assume that owners re-use the original clips.

Roger Furneaux

[Steve Simmons]

From what I understand, the thin modern ones are high risk. I would not put one in my car for any reason. I've heard of several failures.

[Mark McCombs]

Hi Steve,

When you say you have heard of failures of the modern clips, do you mean the thin circlip (open C shape) or the closed spiral type that I have seen?

The closed spiral type is like a closed thin keyring that spirals on then closes back into a solid ring.

Thanks, in the middle of doing thus assembly now so......

[Steve Simmons]

It's been a while but I think it was the type shaped like a C. Moss and others used to sell them. I know the correct type are available from Butch Taras and FTFU.

[jddevel]

I installed new gears but then found could not install original circlip and even partially prevented the drive shaft to turn. Replaced with the new clip and it does now. So what would you do now? I have not changed the drive shaft because no play and good gear on the cam end gear.

[Ray White]

I would say be very wary of the new cir clip. I think you need something more substantial on a par with the original or even put the original one back in. This may mean having the ends of the gears machined like I did. It is possible to reduce them by hand but it would not be as precise as machining.

I have heard some sad tales of expensive engine failures as a result of using the thin cir clip but have had no direct experience.

[Mark McCombs]

I am new to this assembly but after a near miss with this circlip I would not use a replacement open ended clip. As I see it, the driven gear is constantly pulling in against that clip.


FTFU has clever replacement that is a full circular clip that would have 100% of the clip in tension, without an open section that could spring open and allow the clip to depart.

[Steve Simmons]

I haven't run into your situation, so I hesitate to offer advice. But I like the idea of machining the gear to accept the OEM style clip.

[jddevel]

I like the idea of the clip from "From the frame up" however being in the UK probably cost me the proverbial "arm and a leg to get it posted. Especially as the likelyhood of a sensible free trade agreement appears to be diminishing. Apart from co-operation on the weapons and military front!!

[Duncan M]

Some pics of these various retainers would be of interest. The good ones and the bad one.