Gear case woe

[Rgray]

Just as I was getting the hang of my Wng, a problem has cropped up.

Smokey Joe, is named so because it has a leak from the rocker oil feed stud and dripps directly on the exhaust.

I presumed it was fibre washer that was shot but to my horror, the case has a couple cracks and the threads are gone.

I have been looking to buy one but it seems the ones for sale have the same problem.

I might have alu weld, drill and tap it but I have no Idea how to Identify Whitworth threads. Could someone be kind enough to tell me how to?

The part in question is nr. 71 and threads are at nr 85.

[nevhunter]

It's not an easy repair. Try to get a replacement whole part. It doesn't have to have the adjustable oil pressure facility. The threaded bit 85 is the oil feed hollow stud . Around 1954 the case (and cover)changes style at the upper end. Nev

[Rgray]

Ok, cheers.

Ive contacted Draganfly but they are a little slow at replying.. Nothing on ebat either

[Simon.Gardiner]

I can't quite remember what the exact layout/function is for the external drillings in the earlier gear case but about 1950 (I think) it changed to having only one, with the stud for the rocker feed, then 1952 on there were no external take-offs (although the bosses are still clearly there) and the rocker oil feed was taken from the return line.
The change Nev refers to is essentially cosmetic, at the top lug by the magneto the casting changes to be more angular. All interchangeable though and if you're good with the drilling and machining you could probably convert a later gear case to have the earlier oil take-offs.
Your case looks slightly odd but I think the rocker feed is the stud still intact at the bottom of your piccie and that hole with the crack is for the 'pressure regulator' which is only there to make the oil pressure gauge work and (as Nev notes) you can do without that, so if you can blank off and seal up that cracked part your gear case will still be OK.
You might find some info in this thread (also a picture of a gear case with only the rocker feed stud and just the boss where your cracked hole is)
http://forum.arielownersmcc.com/viewt ... f=4&t=1708

SG

[Rgray]

Ahh.. I thought that it was a safety valve of some kind, like on my bsa.

If it's not really necessary then blocking it off is easy enough.

Brilliant thanks!

[nevhunter]

The military ones and later didn't have it. You could just clean the part up and make an aluminium plug threaded to hold it in and sealed with some metal repair magic stuff like DEVCON. It will be a permanent assembly that way so don't put a slot in the plug , ADD a short length of extra aluminium with a neck in it to weaken it and after tightening, (no washers etc) snap the extra off and file it neatly and you won't pick it as a repair. Don't block any internal passages. Check that out. The spring loaded ball in the cam cover case will do the job of keeping some oil flow to the rockers, if it's correctly installed.. There MUST be a few of these cases around still. They get a bit cosmetically damaged sometimes but more repairable than yours is in that tricky place. Nev

[admin]

Does deletion of the oil pressure regulator go along with the addition of the extra ball/spring/cap in the timing chest as backup for the oil feed??
I know the regulator gets deleted fairly early on in the war (ariel is only making single cylinders for the war effort at that point) and is never put back into production post war.
I don't have the parts books for all the WNG's, to confirm date, but the part number suffix of - 41 (2154-41 is for the backup valve plug) indicates 1941 and the 1940 parts list does not contain the backup extra ball/spring/cap

If this is the case, then is regualtor also be acting has a backup for the oil pump feed ?

http://www.arielownersmcc.com/members ... %20125.pdf

[paul.jameson]

Yes, the regulator did act as a backup for the oil feed.

[nevhunter]

Further to my previous post. On the earlier case with the adjustable regulator , there's a bypass passage in the case that allows the oil to escape when it goes past the relief valve. this will have to be blocked, or sealed off (NOT the main one) by a plug with the exterior dimensions of the whole valve assembly that you could weld in, other wise you will get no oil to the big end. I'd chase up a 40 on case rather than bother with this repair unless you like a challenge. Nev

[adrie.degraaff]

I have been looking to buy one but it seems the ones for sale have the same problem.

I have a better one for you, can bring to the rally.