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Sump plate removal intervals?

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Andrew
Posts: 59
Joined: Wed Feb 24, 2021 5:38 pm
Location: England

Sump plate removal intervals?

Post by Andrew »

Hi , just wondered what other people recommend as regards oil change and sump plate removal frequencies .I ask because although I ride the bike regularly and change the oil around 800mls I don't feel it requires the the sump and all the bolts/gasket be removed and then the potential oil leakage possibilities that could occur, at every oil change! The engine has all been rebuilt just a little while ago . What do you folks do ?

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Flx48
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Re: Sump plate removal intervals?

Post by Flx48 »

A good question, Andrew-
I think we all make it up as we go along.

The instruction manual for the early years (50/60/69) made no mention of oil pan cleaning, as I recall, while oil changes were to be at 1000 mi intervals.
The manual for the middle years (50/50S/60/69S) said oil pan removal and cleaning every 7200 mi, with oil changes every 1200 mi.
And the manual for the final years (50US/60US/69US) wanted oil pan cleaning every 16,000 mi, and oil changes every 2000 mi.

The manual differences suggested to me that was BMW was perhaps influenced by two factors; oil and sales.

The '60s was the era when the motor world was transitioning from non-detergent oil to detergent oil; and while people were told detergent was the better way to go, (and we know now it certainly is) many then had heard stories of engine failures due to changing over to detergent oil.
At the time it seemed a mystery, but it gradually became understood that engines run on non-detergent oil had oil sludge deposits caked up inside, and the introduction of detergent oil scrubbed the engine interior clean; and in engines with large buildups (high mileage and/or infrequent oil changes) this often meant plugged oil passages and engine failure.

My first Earles fork BMW was around 1970, and in my world at the time, most stuck with nondetergent for fear of a possible major engine meltdown; at that time crank pulling with /2 bikes were still rather rare even though the engine was no longer being produced, and it was mid '70s before I transitioned to detergent in the BMW.

We know the engine was mostly of prewar technology, and lacked what we would currently call an an oil filter.
It relied on the oil, through oil changes, to be the main remover of contaminants, and slingers also collected debris from the oil, but by that was by default rather than design.
And it should also be remembered that vehicles just didn't last long by comparison to today; my first road car, a '57 Ford, was worn out and junk by 70k miles, just a different time.

The other factor was sales; while they were current, Earles fork era BMWs enjoyed a strong reputation for reliability by comparison to the competition, which in the day was mostly HD and Brit bikes.
Then Japanese bikes exploded on the scene (with oil filters) in the mid '60s, and BMW (as well as HD and Brit) sales plummeted in the latter '60s.

So the improvement in oil technology, and the need to continue to appear low maintenance were perhaps factors in stretching the recommended oil service intervals.

I choose 1000mi for oil change for solo and 800mi for sidecar, and oil pan every half dozen or so oil changes; you're correct the stock steel pan is not straight forward, as even when using the cork pan gasket the steel pan is often deformed by even slight overtightening of the bolts and leaks, and needs to be flattened again to seal well, in that alone the aluminum pans are a plus.
Many also use rare earth magnets in the oil pans, to pull ferrous debris from the oil.

So, we make it up as we go along...
And- one just can't go wrong respecting (hopefully I'm recalling correctly?) Seek's signature line- Oil is cheaper than steel.
Best-
George

Andrew
Posts: 59
Joined: Wed Feb 24, 2021 5:38 pm
Location: England

Re: Sump plate removal intervals?

Post by Andrew »

Thank you George for a very comprehensive and informative reply to my question . I still use straight 40 engine oil which does not have or very little detergent in it , I have thought of 20/50 oil multigrade but I'm unsure . Once again thanks for the reply I shall use my own judgement on this issue re-sump plate removal/clean . Regards Andrew

Seek
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Re: Sump plate removal intervals?

Post by Seek »

Flx48 wrote:
Sat Mar 25, 2023 4:13 pm
And- one just can't go wrong respecting (hopefully I'm recalling correctly?) Seek's signature line- Oil is cheaper than steel.
Best-
George
I can't take the credits :lol: But I like it. Similar to: "Use oil, change often"

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