Indian four oil pump adjustment.

[Ivor]

I just tried with two different gauges, and when I set the spill as low as 50, the adjuster is only in by a few threads. What would be the "Down side" To setting the spill rate to high ? By the way The engineers bored the cases, made oversized bearing shells and white metalled them, but they are white metal bearing specialists and not engine builders.

[Ivor]

Just to add, There is 3/16" tread going into the pump at 50lbs spill pressure, and that's with cold, SAE 50 classic oil.

[Tom Wilcock]

I would guess that if your bearing clearance is set to spec. and using 50 weight oil, then you have little or no oil flow through your bearings. It is all going out the bypass.
Tom

[Ivor]

Hi Tom, I was trying to set the spill rate as Roy and Larry described (With the pump out of the motor ) And I just wondered what would happen if the spill rate was to high ?

[Ivor]

Hi Larry, I have just noticed that somehow (I must have forgotten to press the send button ) I don't think you received the thankyou reply from me ! But, Thank-you for sending the clip that showed Roy setting the spill rate, it was reassuring and not dissimilar to your method, and actually your method showed me the 15 lbs discrepancy on my gauge. Although you set the spill rate with warm oil, the oil will be cold when the motor is fist started, and I'm just wondering what the downside to having to much oil pressure would be ?
Thanks again,
Ivor.

[L Burke]

Missed reply, all good. Your problem is a head scratcher! I agree with Tom, sounds like all your oil is going out the bypass. Too high a pressure is hard on traditional babbitted bearings. Are all your galley's open?

[Ivor]

Sorry guys, I haven't explained it very well. I still have the pump out on the bench and just setting the spill valve, and the adjuster and lock-nut are only wound into the pump about 3/16" deep to have a 50lbs spill pressure. But I guess with a straight 50 weight cold oil, the adjuster would be wound out a fair way.

[L Burke]

At what RPM are you spinning your pump?

[Ivor]

About the same as Roy is showing in his demo. And now I'm looking at the amount of thread left on the adjuster, I don't think it is much different than mine. If I have to, can I take the timing cover off and make a further adjustment after the motor is in the bike ?

[L Burke]

Was the spill valve spring replaced with the proper tension?

[Ivor]

Ha, funny that you say that, I did wonder if that could be the cause, and I messaged JG to see if he would post such a small part over to me. I remember you suggested that I put a new spring in, but it measured up the same as a new replacement one, so I carried out the test with the existing one, but I was hoping to get one shipped over before I assemble it.
I will test it again as soon as I put the new spring in, and post the results on here.
Thanks again Larry.

[L Burke]

Just like a valve spring, they weaken and embrittle with heat and time. Remember, this is a pressure system, not a high volume racing system, at low rpm you want oil to the mains and not spilling. Pressure will fall into lower teens even less if you idle down and lug the bottom end.

This is why knowing the accuracy of your running oil gauge is important....set and regulate your pump using a good "instrument". Then check the difference between the instrument (modern gauge) and your old US Gauge.

[Ivor]

That is really a question for the original manufacturer, if there is no information available I would recommend a pressure in the region of 25 - 30 ibs/ft and certainly not exceeding 40 ibs/ft unless there is solid information to the contrary.

This is the reply that I just got back from the engineers that made and babbited the bearings.

[L Burke]

They know their babbit!

[Ivor]

Hi Larry,
With this information, and if you were in my position, what pressure would you set the spill at ?
Thanks again for all this help,
Ivor.