Better oil pumps?

Hobot · Dec 15, 2013

Ugh did Norton really short change us on its Commando oil pump?
Do our cranks really get enough oil pressure w/o the pump making any excess to show on gauge?
Commoz had to make his pump bigger because he drilled to cam lobes, but other wise with only factory fed items, why do we seek more oil pumping?
Really? Any oil pressure or flow amounts beyond just enough to spare is waste of fuel heating oil drag. Most oil starved surfaces are the cam/lifters and they only get spray and some drip down, so would just bigger pump help them? Are there reports of rod shells oil starving on racers? Really what is the actual need/reason to seek bigger pump?
Did Commando ever win endurance contests before out time?

Hobot · Dec 16, 2013

Still hope to be educated on what down side a trigger happy operator might risk with factory oil pump? [w/o drilled cam or oil jets to supply}

Matt Spencer · Dec 16, 2013

look Familiar ?

NORTON SINGLES OIL PUMP 50/18/16H/ES2 MODELS GSH - http://www.ebay.co.uk/itm/NORTON-SINGLE ... 1206732323

Itd start to get awkward , but machineing out the cover & feed , would get a bit of room for something in there . :?

Rohan · Dec 16, 2013

Matt, WHY are we exploring Norton single cylinder oil pumps ??

They have smaller feed AND scavenge gears.
A roller bearing big end just needs a trickle of oil flowed through it.
And are made as a reverse image of the twin cylinder pumps so they can't be accidentaly substituted for the twin cylinder pumps.
ie they don't fit, if you try and bolt them in...

Matt Spencer said:
look Familiar ?

acotrel · Dec 17, 2013

Towner said:
wet sumping is no indicator for bad pump performance. Gear type pumps are usually reliable and have good performance.

I do hope you are right. My bike always wet sumps which makes me feel the oil pressure might be too low when the motor is running.. I'm used to a 63mm stroke Triumph crank with chromed big ends, and Cooper MIni copper lead big end shells. The button stayed out for ages after the motor had stopped. I suspect enough pressure is needed to float the shells of the journals. I don't think an oil pressure gauge is the answer, I'm hardly even game enough to look at the tacho when I'm riding the bike hard , and that is a must. If I started trying to read an oil pressure gauge, I'd end up in the boon docks. By the time I noticed low pressure the big bang would have occurred. I suppose I could look at the gauge as I was slowing down, however it might be a bit too late ? Until now I''ve just run on faith that the pump is delivering enough.
I will have a look at the manual about resurfacing the pump - that is a good clue - hadn't remembered that.

Hobot · Dec 17, 2013

Alan speaks the truth for those running harsh enough oil pressure matters the most with things zooming in and pilot too focused to do anything but next survival action going where you are looking - as no one really can shut down before something dramatic alerts ya w/o any intrutments at'll. Take my own, piston let go, rod let go, big nuts let go, rings gone away to take seam sealing with it. Still hardly anyone me included is that bezerk in public so the more needles and dials and feedback the more one merges with the blacksmithing going on under you. Coomando has won endurance contests and we time to time get 100,000 mile bottom end survival tales, so did Norton really cheat us or gave us just enough to get by ok.

JimC · Dec 17, 2013

Not having an engine failure from lack of lubrication does not mean you have good oil pressure. Without a gauge you are looking at a go/no go situation. You may be very close to a catastrophic failure, but you have no indication without a gauge. I guess wait until she goes Bang suits some. I think having a oil pressure gauge and/or warning light is a good thing.

acotrel · Dec 17, 2013

Yes, a warning light next to the tacho seems very attractive. Where is the pressure take-off point for the switch ? Ever since I started with the 850 engine, I've always expected a big blow-up. It is not my own good work which has stopped it from happening.

concours · Dec 17, 2013

JimC said:
Nor having an engine failure from lack of lubrication does not mean you have good oil pressure. Without a gauge you are looking at a go/no go situation. You may be very close to a catastrophic failure, but you have no indication without a gauge. I guess wait until she goes Bang suits some. I think having a oil pressure gauge and/or warning light is a good thing.

+1

As mentioned by hobot, watching a gage is not good practice in the heat of the battle... BUT, it's a great tool to view norms, patterns, changes. Cold start, idle, high speed cruise, hot idle... so, if any of these changes, a red flag to look for more clues or reassurance. Being able to make the decision to shut it down BEFORE catastrophic failure is an option I like.

Hobot · Dec 17, 2013

Oh Goody this thread has decayed into more dials bells and lights, Not whitstanding going too fast to pay attention, by far watching the needles move with various delays after throttle changes is gear head educational entertaining. After a while you can pretty well predict what's going on w/o looking. There is too much variation in adequate Commando PSI to make much decision from but run thicker on thinner oil and fret on ride when its going to surprise you or not.

Here's some NOC scope of conversations I could only lurk in on back then
http://www.nortonownersclub.org/support ... l-pressure

Old Brit's with '72-'73 specific oil pressure failure d/t wet sump only when on cam rpm.
http://www.oldbritts.com/n_c_case.html

Norton Service Notes cover Norton's seasoned sage advice, forgetaboutit... hunt for it.
http://www.billymegawatt.com/uploads/6/ ... _notes.pdf

Rohan · Dec 17, 2013

Lets not forget here that only a dozen years or so before Nortons came out with their version of twin cylinder dommie engine, engines DIDN'T HAVE pressurised oiling systems - the oil was just dribbled or splashed into the main and big end bearings, and the lube took care of itself.

Things like T-Model Fords worked like this, and they sold how many millions of them.
Other engines of that era had quite respectable performances.
Oil pressure ain't everything - but it helps....

pierodn · Apr 4, 2014

What needs the pressure relief valve?
A bad working what can do?
Ciao.
Piero

kommando · Apr 4, 2014

Code:

What needs the pressure relief valve?

Without the pressure relief valve the crank seal in the timing cover can be inverted by excessive pressure, you are left then with no pressure :shock: .

Matt Spencer · Apr 4, 2014

A frozen oil pressure relief valve , in a automobile engine , can blow the oil filter apart . repeatedly . untill freed .

Unlikely to stick open , but when hot the oil would have a esy escape & pressure reduced ( perhaps considerably ) at bearings .

Its there to stop overpressureing and blowing the gaskets adjacent oilways .

Bernhard · Apr 8, 2014

One of the things you should check is that you do not have a hole / leak in your oil pump return pipe in the tank, if you have you will get wet sumping via the savage gears.

acotrel · Apr 8, 2014

kommando said:
I would never try it but on Triumphs if the seal goes in the timing cover as long as the oil flow floods the crank inlet then the centripetal force at the big ends will drag the oil through the crank and there will be some pressure at the big ends, but the revs have to be right so at tick over I doubt it will work as the oil will not flood the crank inlet and the pressure will be marginal at other revs.

So the statement just about passes the BS test but only just.

That comment makes me feel much better. I think I will do a calculation of the pressure centripetal force gives at the big end if my oil seal fails. I believe Triumphs usually run at about 80 PSI to stop the shells picking up on the journals. My big bang theory of the Norton 850 motor is looming larger in my mind.

JimC · Apr 8, 2014

Bernhard said:
One of the things you should check is that you do not have a hole / leak in your oil pump return pipe in the tank, if you have you will get wet sumping via the savage gears.

I may be missing something here, but don't all oil return lines have a hole in them at the tank?

nortonspeed · Apr 8, 2014

JimC said:
Bernhard said:

One of the things you should check is that you do not have a hole / leak in your oil pump return pipe in the tank, if you have you will get wet sumping via the savage gears.

Click to expand...

I may be missing something here, but don't all oil return lines have a hole in them at the tank?

Of course Bernhard is referring to a hole/leak in the oil return pipe below the oil level 8)

JimC · Apr 8, 2014

nortonspeed said:
JimC said:

Bernhard said:

One of the things you should check is that you do not have a hole / leak in your oil pump return pipe in the tank, if you have you will get wet sumping via the savage gears.

Click to expand...

I may be missing something here, but don't all oil return lines have a hole in them at the tank?

Click to expand...

Of course Bernhard is referring to a hole/leak in the oil return pipe below the oil level 8)[/quote

I see. I don't have an oil tank to look at, but from the drawing wouldn't the oil level have to be extremely high?

L.A.B. · Apr 8, 2014

Bernhard said:
One of the things you should check is that you do not have a hole / leak in your oil pump return pipe in the tank, if you have you will get wet sumping via the savage gears.

Only if it happens to be a pre-71 (Early Fastback/R) oil tank, or "central oil tank" model (750S, '70 Roadster).

For a '71-on oil tank model, the return pipe enters at about the normal oil level.

Better oil pumps?

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