Oil flow

Lubrication System (oil feed pump and scavenger pump, reservoir, filter, and lines)
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King
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Oil flow

#1

Post by King »

Hi All

I'm breaking in my recent rebuild and the motor is running hot. The consensus of opinion is that it's the new rings getting used to the new bore ("fifty over"). So I am restricting my rides to about twenty minutes and pretty much on flat ground.
My major concern is oil flow. When cold, the oil light stays off but after it warms up the light comes on at around 1700rpm and when hot it is on when below 2100 rpm. I know that this is rather normal for Pans and we should be concerned with flow not pressure. So my question is how does one check flow? I have looked in the oil tank and can see oil spitting around so it probably is OK but is there a better test? Also at what pressure do most sensors operate?

Thanks

King
Cotten
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Re: Oil flow

#2

Post by Cotten »

King!

Don't look now, but modern rings such as Hastings are made to seat almost instantly.
Check your oil return to the tank. If it is healthy, then you need to find a real sending unit.
Heat comes from combustion and friction. It leaves by air.
It's been unusually warm in the States lately, and not what I would call perfect weather for breaking-in a tight, new motor!
A gnat'sazz minimum-spec motor will produce heat initially, and yes, this is certainly a period when it must be babied.
And the oil dumped and replaced super often.
Inspecting the spent oil for "bloom" in the sunlight will give you indications of how the motor is mating its bearing surfaces.
Expect to see some glistening of metalflake in the oil, but hope it subsides in a couple of hundred miles.
Some motors show little 'bloom', which is delightful. Some that break-in slow and painfull still prove to be faithfull in the long run.
The idea is to get through the motor's infancy without trauma.

Good luck!

...Cotten
Pantony
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Re: Oil flow

#3

Post by Pantony »

Magnetic oil plug would not be a bad idea. I also put a full flow spin-on filter (for a shovel) just for the break-in. I have 1500mi on my 48FL and still see some very dark powdery looking metal stuck to the magnetic plug (iron from my cast iron rings and cylinders)
Cotten, could you define "bloom" <Cottonspeak> for what?
Cotten
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Re: Oil flow

#4

Post by Cotten »

Pantony!

By "bloom", I refer to its similarity to algae in a body of water, rather than flowery reflection of light, but either is the closest I can come to describe the billowy metallic iridescence of first-run oil, (or fresh oil from a damaged motor.)
Metal in oil is a fact of life, but obviously we would hope to avoid, or at least quickly eliminate it.
It is not something we could easily (or cheaply) quantify. It would scare us if we did.
I think a great many mechanics have just avoided the worry by never noticeing it in the direct light.

....Cotten
fourthgear
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Re: Oil flow

#5

Post by fourthgear »

king
We had a thread on those oil pressure sending units , how some after market units would do what you are saying yours is doing or not working at all. When I check to see flow , I use a flash light (old eyes need more light ) and look into the tank at the return and after motor warmed up a little raise the rpms to see if it stops the spitting at idle and shows good flow as rpms are increased ( my fluid flowing out is the same dia. as the line size into the tank and shoots to the other side of the tank as rpms increased , due note I'm running a S&S oil pump and the case has been altered to increase/redirect flow to critical parts) and of course the tank warms up with the engine. I am beginning to believe that in some conditions and regions an exterior oil cooler is a good idea, sure we know they were not designed with them and the most part don't need them , but you can't argue with more oil capacity and extra hosing to help cool things off a bit.
Rammy
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Re: Oil flow

#6

Post by Rammy »

I found out how long it takes for 4 qt of oil to go through the motor at about 40 mph!(just 3miles after the return oil line sliped out of the filter fitting . Yes you can see a nice little line of oil for 3 miles down the road. Out of luck I just happened to see the oil lite come on just when it ran out. stk 51 oil pump. good test.
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