Author Topic: More BSA oil pressure problems. A real puzzle  (Read 5443 times)

Offline alanp

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Re: More BSA oil pressure problems. A real puzzle
« Reply #30 on: 26.07. 2013 09:07 »
alanp - was your engine giving full pressure when cold before cleaning the sludge out?  Or where the pressures low consistently?  This is what baffles me as its fine until it gets hot then the pressure dissappers

Yes, I had full pressure when cold.
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Offline alanp

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Re: More BSA oil pressure problems. A real puzzle
« Reply #31 on: 26.07. 2013 09:17 »
HI

Alan, where did all that sludge come from ???
I now remember something similar happening on a Triumph  brought to me some years ago

Jeremy,
A collapsing oil pipe when it gets hot on the suction side is worth a thought????



I used to change oil every year or so and use an inline filter so felt smug about things but didn't remove the oil tank to clear out the bottom of the tank.........also I used a multigrade for a while and then changed back to mono which may have influenced the sludge/gunge formation.

Bear in mind I also changed the oil feed pipe at the same time, i.e. more than one change, so can't be sure which change did the trick, the tank clean out or the pipe. I didn't care really since I got the result I wanted. Suggest both are tried especially as they don't require any more engine parts stripped out which I'm sure Jeremy is fed up with right now.
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Online muskrat

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Re: More BSA oil pressure problems. A real puzzle
« Reply #32 on: 26.07. 2013 10:36 »
Your only on page 2 of your problem Jeremy. Andy just got his problem sorted at page 4.
That's a great idea John. It would best be done with a hot motor and in low/no pressure mode.
I can see Jeremy having a 50 weight shower.
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Offline Jeremy

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Re: More BSA oil pressure problems. A real puzzle
« Reply #33 on: 26.07. 2013 21:25 »
A 50 weight shower - nasty :-)

Offline Jeremy

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Re: More BSA oil pressure problems. A real puzzle
« Reply #34 on: 26.07. 2013 21:26 »
It will be a few days before I can have another go at this.  I will report back tho

Offline Jeremy

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Re: More BSA oil pressure problems. A real puzzle
« Reply #35 on: 20.08. 2013 08:21 »
Well another day spent on this with no change.  PRV was definitely sealed into the crankcases. ( o ring, thick washer, o ring and the prv was slightly proud)  still lost pressure when hot   

I will try the suction side of the system next.  any more suggestions?

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Re: More BSA oil pressure problems. A real puzzle
« Reply #36 on: 20.08. 2013 10:29 »
I had a low oil pressure scare a few weeks ago. Started her up and had 50Lb for about 10 miles. It started to drop slowly to about 30Lb so I headed home. By then she was struggling to make 10Lb and zero at idle.
Turned out to be the oil pump screws (I don't use studs) had loosened 1/4 turn each. Re tightened them with loctite this time. Problem solved.
I don't think your problem will have anything to do with the scavenge side if that's what you mean by suction. Have you tried a heavier oil, say 40/70 ?
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Offline alanp

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Re: More BSA oil pressure problems. A real puzzle
« Reply #37 on: 20.08. 2013 13:52 »
Musky, I'm sure he means the suction side of the pump from the oil tank not the scavenge.
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Offline Jeremy

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Re: More BSA oil pressure problems. A real puzzle
« Reply #38 on: 20.08. 2013 14:51 »
Indeed - I mean the oil lines from tank to pump.

Teh pump has been replaced (several times as I have 3 to choose from) along with its gasket with no change in symptoms.  I could check tightness again I guess

It ran perfectly on multigrade before so should now.

Offline Retired Fireman

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Re: More BSA oil pressure problems. A real puzzle
« Reply #39 on: 21.08. 2013 00:43 »
My ten cents worth: *smiley4*
You stated that you have an A65 oil pump body fitted, is it the late cast iron higher capacity type or are your pumps all mazak earlier type. From memory the late pumps had "O" ring sealing the shaft inside the pump to stop oil transfering between the feed and scavange gears inside the pump if the pump body is worn in the shaft area, is the oil leaking between the 2 chambers when hot. Yes I know you have changed the pump with no result but if the late type pump has the "O" ring missing in all of your pumps that might be your problem.
Now this problem has just happened and you say that you have not changed anything prior to the low oil pressure when hot problem rearing it's head, a couple of bad things that could cause this, one has been mentioned worn big ends, or maybe the sludge plug leaking or if later big journal crank the centre sludge trap flywheel bolt that is drilled into the crank's oil chamber loose or leaking. Muski mentioned the outer part of the combo needle roller bearing being loose and not sealing the old oil hole in the in the timing side case might be the inner ring of the bearing  loose on the shaft journal and not sealing the old oil hole in the crank. Has the outer timing cover an alloy block welded inside it to hold the oil chamber and seal for the crank is this cracked somewhere or is a weld leaking when hot. I would look very closely at the PRV thread as they have been known to leak between the inner thread into the oil relief chamber then bleed off pressure, SRM's PRV as mentioned has the first part of the thread made oversize to "bed into" the female thread in the cases, the instructions they give say that you must back and forth it into the case and there is a torque mentioned that the PRV should give as it initially screws into the cases to form a tight thread. The leak is somewhere keep looking!