Dominator 99 timing case oil filter

Its likely one of the suppliers will have one,failng that I expect a club member will help you out. I may have one myself in an old spare cover.

Hi peter,If I have one you will be welcome to it,I will look today. There has been several types of cover filter assemblies I think. what year is your bike? Not that I know what year my spare cover is!.Perhaps one of the more clued up members will advise if there are diferent types of filters in there, something you will need to know anyway.I'm interested in the internal timing problems of your Mag as I'm fiddling with a 1936/9 BTH mag to try to get the best from it before I give up and bite that expensive bullet.

Hi peter, My spare cover has a casting number 20949 ( if relevant!) and appears to be of the type fitted to a 1960 ish dommy with the Medallion in the middle. It has all its bits. The filter appears to have a spring soldered to one end and looks servicable and not a little cruddy.There is also a spring and piston in the other oilway which may need some teasing out.

Hi peter, As I said, you are welcome to the filter ,no charge. You will have to PM your adress to me , or phone number. It will be a week before I can sort this. Where abouts do you live?.

I find that there are two filtersdescribed in the timing case:

A) Illus. A116 Filter assembly, oil pressure release p/n20280

and

B) No Illus. number and not shown on drawing but listed as

p/n 16946 Filter body gauze

Which one are you looking for? Or both?

Mike

Now that I have had a second thought on this timing case oil filter question, is it possible that the p/n 16946 is a component part of the p/n 20280 assembly?

Mike

From Norvil's site:

20280-USED - SEE LES, HE HAS SOME - FILTER AND SPRING ASSEMBLIES

CAMSHAFT & CRANKCASE FITTINGS

The 20280 filter & spring assembly is part of the pressure release system inside the timing cover & the 067677 is the gauze inside the sump filter drain plug at the bottom of the crankcase.

Personally, I wouldn't use any timing cover with the internal pressure relief valve as I've had bitter experience of them continuously sticking and loosing oil pressure. The combination of the close tolerance fit of a steel plunger running in an alloy casting with unfiltered oil can only lead to one conclusion. Fortunately this doesn't always lead to catastrophic failure of the engine due to the centrifugal suction of oil from the crank.

This is almost certainly the reason why Norton discontinued this type of timing cover which was obviously cheaper to produce, and revert back to the external pressure relief valve type after only 2 or 3 years production (1958 - 1961)

So my advice would be, if you want a filter, fit an external cartridge type and fit a timing cover with an external pressure relief valve. As for your timing cover, the only thing it is good for, is chopping up and used as a timing chain tension tool.

Jim