Ruairidhs pinterest Grasshopper pics.
What are the (steel?) plates bolted on the flanks of the crankshaft?
Do Grasshopper cranks usually have cast aluminiun semi-circular bolt on oil-ways the same as the 2 bearing pressurised engine?

Henry, this is only the second one I've seen in my life but I took the first one to bits, so I can tell you that these plates are, in effect, the oil transfer "cover plates". Oil transfer in the pressurised 3 bearing crank is effected by nerve wracking cross drillings between the adjacent journals. The feed is from the centre main via a deeply worrying drilling at an angle,as far as I can recall, to give the least possible interference with the slim centre webs. The angled cross drillings between adjacent big ends intersect in a sort of mishmash-cum-gallery at the surface of the crank web and are sealed by those little cover plates. There may be a shallow milled recess in the back of the plate, not quite certain of that. I hope this description makes sense - it's over 40 years since I saw it!
I think the engine I examined must have been a late pressurised Nippy engine because it had an 8 stud block. I should have taken pictures but I don't think my 1964 Instamatic would have given very good results!

Regards, Stuart

Stuart,

If the oil feed goes from the centre main then why is there an oil pipe to the nose cone?



R

Location: The 3D shed, Tewkesbury

Ah, maybe the centre main oil feed is just for itself, that would make a lot more sense and those frightening drillings just take the oil through the middle of the centre main to the two rear journals. Well, it was a long time ago, Rob! I didn't do too badly considering!

Regards, Stuart

Stuart mentions the scary drillings through the centre webs. Reliant did the same thing later with their side valve engine but to feed only journals 2 and 3.
Journals 1 and 4 were fed from front and rear main bearings.

How thick are the centre main webs? They certainly look thicker than standard 3 bearing.
What is the dia. of the big end journals?
I would hazard a guess that the centre main oil feed supplied all 4 big end bearings and that the pipe to the front end was to ensure a plentiful oil supply to the timing gear and supercharger pulley drive gear and bearings.

I spent some time searching the Motor Sport digital archive for Harold Biggs' article of Jan. 1947, "Entomological Dissection". I should have just looked in the "Motor Sport Book of the Austin Seven" where you will find it on p.54.
I had remembered the big end size as 1 and 5/16" and it seems this is so. There was uncertainty about how the oil was distributed but I do wonder if the suggestion that the nosepiece supply feeds 1&2 and the centre main feeds 3&4 might be correct and persuaded Austin they could dispense with oil transfer pipes a la Ulster/Gordon England.Perhaps an owner will tell us?

Regards, Stuart