As i mentioned in an earlier post i had to replace the oil pump drive spindle on the M20 and decided to replace the 1/2 time pinion(with pattern)working on the basis that mating the new and old teeth together was not good practice.When i came to fit the outrigger plate--no chance.Turns out the diameter of the new pattern pinion that should slide into the bushing is approx. 8-10 thou.oversize compared to the origional part.
It made me think that if the people that make these bits can't get the basic dimensions right there is no chance of them using the correct metals or getting the hardening process right. Anyway rant over i'm just glad i'm doing the rebuild for pleasure and not for a customer.
No more pattern parts for me,N.O.S. or serviceable second hand-thats the way forward

email (option): sally_jones@btinternet.com

Hi Mick..It is certainly the case that a good useable part will often be better than a pattern one and it is the way to go if available.
Personally I wouldn't risk it anyway on something as vital as the oil pump drive unless I was absolutely sure that everything was 'up to scratch' and the part came from a supplier I had confidence in..ie with a good track record..ABSAF for example. If a mudguard doesn't fit quite right or the rear carrier doesn't look like an original there aren't really any consequences, but the more highly stressed parts of unknown origin?...no thanks..Ian

email (option): ian@wright52.plus.com

Hey Mick,

I'm with you on that! Rick has sent me a book on British Steels, and I have several Metalurgists as friends. A chemical analysis can be had for as little as $75.oo over here. But, with modern steels, making a choice is a bit easier.

It seems that with todays modern technology, we can make our own stuff. I design and make tools, and have just finished the gearbox sleeve nut spanner and a gauge for setting up the distances of the rear frame.

Piece at a time, I'm drawing the parts, but not making them as I have no idea as to demand. The Matchless owners club has a nifty spares scheme though.

Reverse engineering as to critical dimensions with old parts is dicey at best. If a NOS part is available, you still have manufacturing tolerances to make a desicion on.

If we can get enough fellows on board, I'd be more than happy to lend my expertise to the cause.

Cheers,

Robb

email (option): britool51@hotmail.com

Robb, Andrew engineering in the UK makes Matchless parts at quite reasonable prices for stuff that is made properly, look him up on google

email (option): davmax@ntlworld.com

Hi all,
After overhauling by engine sometime ago- top to bottom with EVERITING NOS beside barrel,
I replaced all the timing parts with new: idler, cams, and the Engine Shaft pinion.

Then, before closing, I rotated the engine manually, and to my great horror I heard a terrible gridding noise,
As if I am not turning an engine, but grinding coffee beans.

The marks on the marks of point and stripe (-/.) on the new Engine Shaft pinion looked strange, so before opening the case again,
I replaced it with the good old one and turned the engine- and to my great relief, it turned like the engine is filled with hot butter.

It turns that the sprocket was a pattern one..

Noam.

email (option): noam10@gmail.com