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Low oil pressure - im looking for clues

harris5950
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Joined: Tue Nov 16, 2021 7:43 am
Location: Mobile, Alabama

Re: Low oil pressure - im looking for clues

Post by harris5950 »

Good for you for sticking with a problem. Problems like this have made many old bikes end up on Craigslist or end their lives forever.

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srankin
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Location: Spencerport, NY USA
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Re: Low oil pressure - im looking for clues

Post by srankin »

Reading your solution is interesting and your conclusions make perfect sense. I can't pull the pump apart on my two bikes but I "think" the o rings I installed were both red? Sorry, I can't say for certain. As to getting the part from a BMW dealer, sadly, mistakes happen. LOL, I just bought needles and jets for a pair of carbs I am rebuilding and ordered the wrong ones because I didn't take a few extra seconds to check numbers. Not saying you ordered the wrong part but perhaps the guy who sold it to you looked up the wrong part or, the shop has the wrong part under the right number?

When You are cranking the bike over even before it starts running, the oil pressure light should go out. The starter with a good battery is fully capable of cranking things over to build up the minimum necessary pressure. In fact any time I change y oil filter, I crank the bike until the light goes out before actually starting the bike and running it.

Thanks for documenting your work and sharing it, it is something to file away for future troubleshooting. St.
Owner of a 84, R80RT and 78, R100RS

P-Funk
Posts: 15
Joined: Wed Nov 17, 2021 2:20 pm
Location: baltimore suburbs

Re: Low oil pressure - im looking for clues

Post by P-Funk »

The oil light in the dash was not lit because I have the gauge installed where the switch should be. So, no signal there.
I have to replace the switch, but in the meantime, the actual gauge value is certainly more informative than the low pressure warning. I'd rather see an actual metric reading than just a low warning, right?

I'm not sure how I feel about the dealer O-ring mix up, I assume it happens, but, I find fault in myself for not knowing the importance of the proper gasket thickness.

I got the moto out of my basement after posting the recent update. It idled well enough for me to mount the steed and drive it through my yard, and around the house to the garage. I glanced and saw the pressure gauge reach 115psi with revs between 2-3k, which makes me think about the over pressure valve and spring, and at what point does that mechanism comes into play. I was happy to see those numbers at all.

I have plenty of other details to chase after, but i am chuffed with the feeling of resolution on this issue.

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srankin
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Re: Low oil pressure - im looking for clues

Post by srankin »

I don't see any reason to be feeling bad about the o ring mix up. You purchased a part from a dealer and expected to get the correct part. I for one don't measure the thickness of gaskets or o-rings each time I replace them, I count on the right part as listed in the microfiche or on the word of the parts department person.

Of course you are correct, the light is only an indicator, much better to have the actual numbers at hand.

LOL when I bought my first new bike, I asked my dealer at the time about putting an oil pressure gauge on instead of the clock. His response was, by the time you see the loss of pressure on the gauge, there is a good chance damage is done. The idiot light works faster and just as well. A clock on the other hand will keep you from being late to places you have to be like meeting the wife for lunch. I have found his words to be very true. Luckily I have never had a major failure of oil pressure but, I have had minor issues with the damned oil filter rings and the light flickers telling me something is wrong.
Enjoy the ride. St/
Owner of a 84, R80RT and 78, R100RS

P-Funk
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Location: baltimore suburbs

Re: Low oil pressure - im looking for clues

Post by P-Funk »

It occurred to me that this topic needed to be updated after what I learned yesterday.

I re-visited the dealership where I bought all of my parts and explained my oil pressure saga to the parts department rep. We reviewed all of my orders over the last year, and part numbers. When I finished, he asked me to wait while he went to fetch the proper oil plate o-ring to ensure that the part numbers matched. When he did return, he had in his hands 2 o-rings- the normal and known to be good pink o ring that should be used- AND - a thicker black o ring that was identical to the unit that was sold to me in January of 2021. He looked up and me and said: These two o rings are in parts bins that are right next to each other, and, it appears as though you were sold the wrong O ring.
WRONG O RING!?!

The thicker black O-ring was certainly the problem, and it was certainly sold to me by accident, and, not knowing otherwise, I installed it.

Now I am on to determining if there was any damage to the motor because of the low oil pressure situation. I was advised of a few areas to look at and determine by the actual, and friendly, mechanic at the dealership.

porter

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srankin
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Re: Low oil pressure - im looking for clues

Post by srankin »

Well, Porter, it is nice to know your parts guy is good enough to admit his mistake and thanks for investigating to find this out.
In all honesty, I wouldn't worry about damage to the engine from this experience. You never really lost oil flow or total pressure, it was low. You didn't put a ton of miles on or run the heck out of it either.

I would ride the heck out of it and if it starts to burn oil, or act strange, then I would tear it apart. Keep an eye out in the oil filter for metal bits or more than normal dirt. If a lot of stuff shows up in the filter, maybe then a tear down would be in order.

That is my take on it, others may suggest something else. I have seen airheads subjected to worse abuse and still they run. St.
Owner of a 84, R80RT and 78, R100RS

LesCriess
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Re: Low oil pressure - im looking for clues

Post by LesCriess »

I'm new to BMW bikes & Airheads; but I've wrenched on a lot of bikes. This has been a fascinating read and a lot of info on good, logical investigation. Well done & thanx!!
SW Washington Coast, another half mile West & you're wet!
'73 R75/5, SWB, '76 'Wing, '49 Willys truck

P-Funk
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Location: baltimore suburbs

Re: Low oil pressure - im looking for clues

Post by P-Funk »

Im adding the following, for the folks like the one above this post, who might learn something from my bad experiences.

The shop's mechanic suggested the following, after listening to my saga:
-drain the oil into a clean pan - look for bronze dust, that might point to connecting rod wear, although he did not highly suspect that those had been damaged.
- take out the oil filter and cut off the metal ends, unfurl that, and inspect it for any metal debris- needle bearing dust, anything really. Because this oil was only slightly used (10 miles), it should show up.
- do the following again after some miles have been put on, just to ensure the search for wear.

lastly - take off the valve covers - inspect there for needle bearings - as they might have been spat out by the rocker arm.

If I really want to go the extra mile - remove the valve covers AND the cylinder heads, pushing out the wrist pins but leaving the pistons in the bores, allowing a viewpoint whereby the nikasil lining of the cylinders can be inspected for any scoring, wear, due to the potential lack of lubrication. And, while there, grabbing a hold of the con-rod and ensuring that there is little to no play in their connection.

I mentioned the large bearing on the nose of the engine and the timing chain area - he shrugged and said meh.

I bought the oil and another filter, and minor bits, and was charged $47. No offer of compensation for the agreed upon mistake. I got hopes and prayers, and a slight mention of apology. This issue caused me some significant frustration, along with alot of time, and some money for replacement parts, a huge hassle in the end. It still burns me now, and, this is why it is not over for me. At least not yet.

jnclem
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Re: Low oil pressure - im looking for clues

Post by jnclem »

I’m back, and still having low oil pressure issues. Replacing the canister definitely helped, but the oil pressure is still not what it should be. I now have the front cover and timing chest off again to replace the Oil Pressure Relief valve. Unfortunately, when you back the housing for that valve out, it runs into a stud in the case before you can remove it. I haven’t seen anyone else mention this, but there is no way to get that relief valve out without removing that stud.

I spent an hour or so trying to remove it using heat, penetrating oil, etc, with two, and then three, nuts threaded onto the stud, but it won't budge. I’m going to ruin the threads or break the stud if I keep this up. So, for anyone who has done this job, did you have to remove the stud to get that relief valve out? If so, how did you manage it?

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schrader7032
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Re: Low oil pressure - im looking for clues

Post by schrader7032 »

I checked my /7 repair manual from BMW thinking it might have something, but I don't see anything about the oil pressure relieve valve. Typically, the repair manual is for the BMW-trained mechanic where the "typical" or "usual" stuff was covered in tech school.

I see you posted on the MOA forum. That's good. Hopefully someone like Anton Largiader will see it and offer some advice. :!:
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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