Ariel 350 Red Hunter oil pumps and oil pressure / delivery discussed.

One of the last jobs to do on this Pre War Ariel 350 was to fit a decent oil pump. I was a bit surprised to find a new, high capacity oil pump gave lower oil pressure than the tired original type - here's what I found ...

[@thra5herxb12s]

I needed to put the 1952 pump back in my W/NG after borrowing it to test my VH engine. The 52 pump has a bigger feed than the pre and post 1949 units, but discussion on all the forums seems to think that all the extra oil isn't a good thing, causing oil leaks and smoking, due to the extra oil getting sucked down the inlet valve guide, and also the extra oil being flung around by the flywheels before it's scavenged back to the tank. When looking for a pump to replace the 1952, I wanted any pump that worked, that I could just buy off the shelf, so I decided on the Hawker pump having slightly bigger plungers than the big Ariel pump that the engine seems to get on with. Testing it for a few wet miles it performs pretty well with no extra leaks and no smokey exhaust either, and being brand new it should last longer than me.

[@classicrider5274]

When you did this, did you have an oil control ring on the piston or three plain ones?

[@thra5herxb12s]

I am on my forth Ariel single now,a 1940 W/NG. My 1938 500 sprinter that I raced in the early 90s, Was fitted with a cut down Triumph pump. The feed plunger is the same size as the return of the standard pump, with a slightly bigger return. Yes, if you have increased capacity you will get less pressure. Try putting your finger over the end of your garden hose. The extra oil is better than higher pressure in the Ariel because it has roller big end bearings. In a plain white metal bearing you want higher pressure to prevent metal to metal contact. Although I wouldn't take the reading on the gauge as actual pressure, more an indication that it is flowing.

[@paulhenshaw4514]

The 'pressure gauge' only gets a reading thanks to the ball and spring at the front of the timing cover, which, as far as I can tell has the sole purpose of creating some pressure for the gauge to display, between the pump and gauge outlet before oil goes on to the engine.

[@A65Bill]

Very interesting, thanks. It'd be good to hear what Morgo offer by way of explanation, too.

[@charlesmattina3787]

Thanks for the video. Helpful.

[@paulhenshaw4514]

You're welcome!

[@mikedearing2588]

very helpful.. I suspect that the oil pressure guage can be ignored :-) the other feed looks way better though whats lubing the top end?

[@lottierose8668]

wich oil is used in that engine 50 or 40 weight

[@paulhenshaw4514]

20/50.

[@lottierose8668]

@@paulhenshaw4514 is that with an external filter ?

[@noelshed689]

What better 350cc or 500cc ?

[@paulhenshaw4514]

Both are good, the 500 has more power, naturally.

[@thra5herxb12s]

The 350 has a hard life keeping up with the traffic. The 500 can maintain its speed at lower revs and pulls better into the wind and uphill and fully laden with camping lugage etc.