Oil Pressure

[paul.jameson]

Mark,

The pipe from the crankcase feeds the inlet guide, although Ariel did experiment with it also feeding the exhaust guide. I don't know which years in the 1930s saw which level of experimentation. What I do know, from hard experience coupled with advice from old time open valve riders is that the exhaust guide is adequately lubricated by oil from the cylinder PROVIDED you use a plain ring piston. If you use one with an oil scraper ring, you will starve the exhaust guide of oil and it will wear out quickly. My record is 50 miles.

[satchison]

I have basically the same setup on my 1947 NH 350. I noticed the oil pump gasket almost completely covers (restricts) the oil feed (spring-ball valve) inlet once installed. Is this normal?

[paul.jameson]

You should find that the hole in the gasket allows oil to pass along the slot milled in the timing case face to the spring loaded valve, behind the gasket itself.

[satchison]

[img]

[/img]The piston on my 46 NH 350 has 3 compression rings. Draganfly tells me that their replacement ring kit for that engine has 2 compression rings and 1 oil ring. Can anyone identify this piston?

[pete.collings]

It looks very much like a WNG piston, which should still be useable, there are rings available to suit. Advice previously given on this forum is to use the earlier type of oil pump with this type of piston, with the small feed plunger, as the piston is less able to cope with the increased oil supplied by the later pump with an increased size of feed plunger.

[nevhunter]

I can testify the 3 comp rings is entirely satisfactory with the original pump. My W/NG has been running undisturbed from the original assembly in the late 90's and has worn out a rear tyre and the engine blows no smoke . Numerous people have confirmed this. The oil ring equipped pistons co-incided with the larger delivery side pump. 1949? According to the factory the extra oil was to quieten the piston as the alloy used required a fair bit of clearance to run without seizing. Nev

[satchison]

Thank you gentlemen. I will search for a set of 3 compression rings (+20) for reassembly. I believe I have an earlier oil pump. Is there an easy way to identify early vs late pumps?

[dave.owen]

There should be a date stamp on the face of the pump,

Dave

[nevhunter]

The delivery plunger is the smallest used. Not all pump faces are stamped but where done it has numbers relating to the year made. I think I recall a 49A on one with a bigger plunger. If the plunger and/or body are worn the flow could be unreliable . It's only a very small area that needs to wear. On the end and near the port of the plunger and body respectively.. Nev

[satchison]

Here is a pic of my pump. Darganfly tells me these rings are n/a available. Do you have another source for these rings?