Author Topic: oil flow  (Read 2336 times)

Offline RichardL

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Re: oil flow
« Reply #15 on: 24.08. 2017 04:57 »
I'm in Channel Islands (where the cost of living is twice that of UK - average cost of a 3 bed house here is £500k)

So, either off the coast of France or California, and either sounds great. I'm more familiar with those off of California.

I once had oil flow problems due to a spider's egg sac left in my in-flow nipple while the bike was apart for rebuild.

Richard L.

Online KiwiGF

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Re: oil flow
« Reply #16 on: 24.08. 2017 08:40 »
Just my 2 cents, the standard pump can generate pressures in the region of 60psi probably much higher, and as far as I know the pumps return pressure can equal the flow pressure.

In practice there is very little restriction in the return circuit so the return pressure never gets anywhere near what the pump is capable of.

The pumps probably operate almost in "constant volume" mode due to their gear type design, so a restriction just increases the pressure, without much drop off in volume pumped. That's a theory, I've little to back that up!

The flow pressure should reach the pressure return valve limit (60psi?) when the oil is cold, but once its hot the pressure may drop to worryingly low levels on tickover, and even when cruising quite fast the PRV does not operate, well that's what some have said on this forum.

Given the above I am wondering if the oil is either returning to the tank via a leak in the pipe inside the tank? Or maybe too much oil is going through the rocker feed? (Easily checked by blocking it off temporarily). Having said that, the return volume to the tank must be at least be equaling the flow volume as otherwise the tank would run dry.

Another possibility would be lack of oil supply to the pump, it is largely gravity fed, so even a small restriction in that part of the flow circuit eg a collapsed pipe, or blocked gauze filter, could cause a problem.
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts

Offline duTch

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Re: oil flow
« Reply #17 on: 24.08. 2017 09:17 »

 I had the notion that the scavenge gears are wider than the feed gears, which enables the scavenge side to pump volume faster; (obviously to avoid congestion)
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline BSA_54A10

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Re: oil flow
« Reply #18 on: 24.08. 2017 10:34 »

 I had the notion that the scavenge gears are wider than the feed gears, which enables the scavenge side to pump volume faster; (obviously to avoid congestion)
It is but as it has the same working clearences it is capable of pumping to the same pressure.
However a pump can not generate pressure if there is nothing to hold the pressure at the outlet.
The usual reason for low oil pressure is not the pump but the whopping big gap between the bush & the crank.
Bike Beesa
Trevor

Offline coater87

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Re: oil flow
« Reply #19 on: 24.08. 2017 11:21 »
 Thats why I still believe he needs to set up a container he can watch the oil being pumped into the motor through.

 If oil is not going into the motor, its not coming out either.

 If the scavenge side is screwed up, he is going to have a sump full.

 But either way, its time to figure out whats going on before something really bad happens.

 It could be like mentioned already, it could be as simple as the feed side pipe could be collapsing down under suction. *dunno*

 Lee
Central Wisconsin in the U.S.

Offline RDfella

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Re: oil flow
« Reply #20 on: 24.08. 2017 11:44 »
Thanks to everyone for taking the trouble to wrap your minds about my problem.
To start with kiwgf:- the possibility of return to tank leaking inside tank is interesting. I had the back off the tank to repair it and am pretty certain the pipe is OK, but I will check that. If the flow to rockers was excessive, surely it would eventually wet sump? There is a good flow from tank to pump and both hoses to tank are new.

Coater87:- I agree that this needs to be sorted before the engine gets damaged. Both flow / return pipes have new hoses and flow to pump (at point where pump mounts) is fine. This seems to point to the pump itself, but inspection showed it to be in good condition – as was another pump I tried with similar results. Arrrgh! Maybe I should have scrapped it after all and used the frame to mount my new engine! Will try to post a picture of that when I get time.

P.S. – forgot about the US channel islands – rather like the old Jersey and New Jersey. I’m in the ones near France. 
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Offline duTch

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Re: oil flow
« Reply #21 on: 24.08. 2017 12:56 »

 So is all very interestigk...unless I missed it, what kinda revs are you doing to achieve little return ?

 Took a look on Gogle Earth and holy dooley- to do a decent days ride, you'd have to do every bit of road on whatever Island you're on, otherwise you'll be going past the same pub every 10 minutes *beer* *beer* *beer* *eek*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline RDfella

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Re: oil flow
« Reply #22 on: 24.08. 2017 17:33 »
DuTch - from a fast tickover to a 'good blip'. Given the flow rate I daren't run it too high for fear of picking up a bearing. Most of my other bikes are all ball or roller brg, so flow is less important (even though they have several times the flow as this A10!)
You're right about 'decent rides'. Have to travel to France or UK for that.

Following a suggestion I've checked the return pipe - as there's no flow to the pump from the return (which there would be wewre the pipe leaking below the oil level) I'm satisfied that's OK. Pulled the pump off - again - this morning to look at the gasket, as someone suggested. Holes line up reasonably well but could benefit from being larger, so I made a new gasket (of same thickness material so as not to distort pump given the 3rd mounting point). Will run the engine this evening to see if there's any improvement. I'm getting really pi**ed off with this so if it doesn't improve not sure what I'll do. Too late to scrap the bike as a lot of work has been done restoring the cycle bits and the engine I originally intended putting in won't fit without major surgery, so it's too late for that as well.
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Offline RDfella

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Re: oil flow
« Reply #23 on: 24.08. 2017 18:05 »
Grateful to everyone trying to help me. As mentioned in my previous post I realised the return pipe wasn't leaking in the tank - and thereby telling me lies - because if it had been oil would flow back to the pump and be evident when the latter was removed.
Checked the pump / crankcase gasket whilst the pump was of (yet again) and found the holes lined up reasonably well - but could have been better and larger. So made myself a new gasket and tried the engine again this evening. Substantial flow back to tank at last.
Round of applause to julianS who suggested (as did others I think) that the gasket might be at fault. Whilst the line-up wasn't dire, nevertheless it must have exacerbated the imperfect alignment of pump / crankcase holes.
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Offline RichardL

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Re: oil flow
« Reply #24 on: 24.08. 2017 19:00 »
Yay!

Offline RDfella

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Re: oil flow
« Reply #25 on: 24.08. 2017 19:29 »
I mentioned in my previous posts that I bought the G Flash originally just for its frame to house an engine I was building. Pic attached. It has Yamaha XT cyld heads, but the rest is mine - except the A10 gearbox (plunger type).
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Online Greybeard

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Re: oil flow
« Reply #26 on: 24.08. 2017 20:22 »
I mentioned in my previous posts that I bought the G Flash originally just for its frame to house an engine I was building. Pic attached. It has Yamaha XT cyld heads, but the rest is mine - except the A10 gearbox (plunger type).

 *eek*

In that case I'm sorry I patronised you earlier about BSA oil flow; you clearly do know a thing or two!
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Offline RDfella

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Re: oil flow
« Reply #27 on: 24.08. 2017 21:59 »
Nothing to be sorry about. No-one is above learning and remember it was you guys that sorted my problem. I was stuck and wouldn't have considered the gasket until someone suggested it.
Attached an earlier creation of about 25 yrs ago. M21 frame, modified B21 heads and barrels, rest my own.
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.