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Oct 8, 2014 - 4:21PM

Exhaust and inlet timing gear piinions

I am restoring a 1942 wm20 and am part way through the engine rebuild. The two timing gear pinions were removed to install the tappet rods and noticed that both timing gear pinions had their bases filed with solder? At first I thought it was carbonised solid oil , but obviously someone has purposely blocked these oil ports. The fact these oil ports should lead to/ from the crank case makes me wonder why they are blocked or if this could be like this from manufacture? Can you shed some light on this as I can't find any info on this

Thanks
Clive
Australia

email (option): Clive1960@bigpond.com.au

Ian Wright

Oct 8, 2014 - 4:32PM

Re: Exhaust and inlet timing gear piinions

Hi Clive...These are the cam spindles..The type you refer to are the early type...They were drilled all the way through and then the back was filled with solder...

The cams and spindles are fed with oil from the front via the timing cover oilways/rubber seals and special cam spindle bolts...

There was a second version that was not drilled right through during manufacture (to simplify production) and a third type that were modified slightly to reduce pressure on the main bearing housing during fitting...The last type were 'handed' and marked 'in' and 'ex'...

Any of the three types will work OK...Ian

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

Pete C

Oct 8, 2014 - 4:33PM

Re: Exhaust and inlet timing gear piinions

Ian got there while I was writing. I misunderstood and thought the spindles were "filled" with solder and so blocked. Learn something new every day here

Hi
I assume you mean the cam gear spindles, in which case I reckon the oilways are there for a good reason.
They are fed over the timing side cover with rubber seals and lubricate the cam pinions which have to rotate with the force of the valve springs forcing them into contact with the spindle. How are the bushes in the pinions? was it run like that at all?

Good luck
Cheers
Pete

email (option): petercomley@web.de

Clive Hebbard

Oct 8, 2014 - 4:48PM

Re: Exhaust and inlet timing gear piinions

Thanks so much for the info. I purchased this bike in about 1980, the guy I brought it from drove it into his shed 20 years before that!
Anyway, after over 50 years of never being started we spent a few hours tweaking and first kick it jumped into life! Unbelievable!
Slowly slowly it's coming back together, the cam pinion spindles being blocked at the base threw me, but sounds like I don't need to drill them.

Awesome to get responses so quickly, thanks.

Clive

email (option): Clive1960@bigpond.com.au

douglas

Oct 9, 2014 - 12:34AM

Re: Exhaust and inlet timing gear piinions

After sitting for 20 years I'd be surprised if you haven't sheared the oil pump drive gear.