Valve Guide lubrication (rate) 5

[477stephen]

Hi there
Has anyone else noticed the decline of the "internet"?

Cant seem to find any information on it these days

I have an older engine Single cylinder British bike. I have a high rate of valve guide wear. Due to inadequate oil supply ( 25cc at 3000 rpm ON a good day ) so I needed to know what would be an acceptable oil flow the only reference I can find says about "Normal values lie in a range of from 0.007 to 0.1 cm 3 /10 h" ( 3 x 10^-6 cm~3/secomd?)
Does anyone have any information on Valve guide lubrication rates?

I really appreciate any help you can provide.

Stephen

 

[3DDave]

Just double the amount. If that doesn't work, double it again. When a cloud of blue smoke trails you then you will have added almost enough. I'd just add a hamster water bottle filled with oil so it taps the ball bearing at the end of the feed tube at mid push.

 

[477stephen]

Just double the amount. If that doesn't work, double it again. When a cloud of blue smoke trails you then you will have added almost enough. I'd just add a hamster water bottle filled with oil so it taps the ball bearing at the end of the feed tube at mid push.


Hahahahaa its almost to that point !

I have emailed a few manufacturers , have a list of books that I will try and get and I know the precise terminology I have to use in search engines

As its a brit single , you know its probably quicker to drop the rocker cover drill a hole in the rocker block ( aimed at valve guide) and watch mirror for a very clouds of blue smoke and or a very angry young Swedish girl

in an Ideal world however I would like to think twice, cut once

I will report back if I get any information

Kind regards Stephen

 

[waross]

I hope that you have cleaned all of the sludge and carbon from the old oil passages.
It wont take much restriction to significantly limit the oil flow on a low pressure system.
If you want more oil on the valve stems, try slightly damaging the oil seals on the valve stems.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[XR250]

Well, I'm an Amsoil dealer so my answer is that the 10W-40 Motorcycle oil will solve all problems
And I disagree about the CR250. And I sold the XR250 as I prefer riding my mountain bike.

 

[TugboatEng]

My local Honda dealership used to build the XR650R's that were used to race the Baja 1000. They did not have good things to say about Kibbelwhite valves. In fact I had them repair a cylinder head that had KW valves that were severely recessed. The OEM Honda valves were far superior.

 

[mfgenggear]

I planning to get an ebike, mild trail riding. Miss cruising the desert at winter, not summer.
First time I slept on on the desert floor like a nut. Yamaha Enduro 175 Yamaha 250
Don't re.ember the model.

 

[gruntguru]

I don't disagree with the earlier knurling suggestion.
If done correctly the loss of surface area could be minimised.
Circumferential grooving would minimise oil-loss.
The grooves would provide reservoirs for oil.
A few grooves spaced at slightly less than the valve lift would ensure the entire stem would pass through an oil reservoir at some point in the cycle.

je suis charlie

 

[MintJulep]

This paper might be useful to you.

Optical Ways to Improve the Tribology of Valve Guides

https://www.sae.org/publications/technical-papers/content/2005-01-0586/

 

[Tmoose]

Does the new valve stem have plating of some kind ?

Can the valve guides be identified as iron or some flavor of bronze ?

I'm sorry if I missed if both intake and exhaust valves are not fairing well.

Modern Chevrolet LS engines have remarkably low wear rates.
I don't know if their materials would be as successful when air cooled.

I'm sorry if I missed it when you identified what brand etc oil you are using.
Some of the almost magical claims for synthetic oils are based in fact.

The late great Smokey Yunick maintained that valve guides honed to size wore MUCH better than reamed or bored guides. I believe him.
Again water cooled not air cooled, but severe operating conditions to be sure.

 

[mfgenggear]

Old school bronze valve guides.
The new synthetic multi viscosity
Fine weight is for new tight tolerance e components in the engine.
Old classic engines were not as close tolerance components so needed higher weight and viscosity. It's not uncommon
To run 40 weight oil.
One trys to run synthetic oil in these engines it will ruin it.

 

[gruntguru]

Heavier weight synthetics are available and will not ruin the engine. Quite the opposite.
(Although compatability can be an issue with old seal materials. Another issue is with badly worn and carbonised engines where synthetic solvency can cause issues.)

je suis charlie

 

[mfgenggear]

I don't agree, I stay with old fashion sae 30 weight or 40 weight. Or sae 10w_30 wieght.thank you

 

[gruntguru]

Your post doesn't explain your aversion to synthetics. You can buy synthetic oil in any of the three weights you mention.

Is there a reason that synthetic will "ruin" an engine other than selecting the wrong viscosity?

je suis charlie

 

[477stephen]

Hi all update time

I spent some time looking at the lubrication system on the old girl. Threw, it at a CFD ( OpenFOAM ) software and as I originally thought

the guides simply are not getting enough ( read any) oil. also the guide is boundary then mixed ,,just touches full film .."in theory" before descending back into that maddening crowd )

Those with a nervous disposition, you might want to turn away now;

@3000 rpm coming out of the rocker block and "Supposedly" heading over to the valve guide ( it hasn't the momentum so just pools slightly then heads back down the pushrod tunnel) u have 1/2 a teaspoon of oil of laminar flow ( Rey 180 ) at about 1/4 psi ( basically bugger all)

ON top of that, build quality

the feed to the big end is through a quill feed, IF you tighten or use a different fibre washer you effectively block the oil supply which in turn reduces the supply to the valve guide

AND on top of That the clearances, and build quality of the oil pump(s) "assumes" the ports all line up.. yeah right

So went through, opened up feeds, chamfered faces, used a larger return pump and reduced the spring pressure ( the oil pump lifts off its face to allow some kind of bypass )

( reducing the spring pressure allows a larger pump to be used as the worm drive is fragile ( I did all I could do and STILL its a bit "stiff" to turn should be thumb pressure "ish" )

I wont know the "outcome " of all this until I install new guides and seats which I will do over the winter ( the old girl is going to get a respray, new rings and valve guides and seats and ONE day an up graded alternator and rewired with better connectors

I did get replies from manufacturers"
This isn’t information that we have for our valve guides, so unfortunately we have no input to share on the matter." ( YIKES you fellas MAKE valve guides ! )

I have new guides in stock unfortunately I don't know what "type of bronze they are ,, but attention will be paid to clearances

oh and as for "seals " the enfield doesn't have any ,,there is a cork quill feed seal and 2 or 3 fibre washers Ill throw Mobil sae 10 50 diesel synthetic in there next time these things are not "high tech " but do have "needs"

Stephen

 

[TugboatEng]

The valve stops twice per revolution of the camshaft. There will always be boundary lubrication during these stops regardless of the volume of oil supplied. This is where the wear occurs. Modern engines last longer due to better material selection, not more lubrication.

Have you even identified the valve stem and guide materials?

 

[477stephen]

The valve stops twice per revolution of the camshaft. There will always be boundary lubrication during these stops regardless of the volume of oil supplied. This is where the wear occurs. Modern engines last longer due to better material selection, not more lubrication.

Have you even identified the valve stem and guide materials?


Sorry for being blunt

but have you even read the original question or the thread,

I don't even know how to reply to this

please don't reply if you have nothing of substance to add

Sorry

Stephen

 

[TugboatEng]

Different materials are going to require different amounts of lubrication. It's important to identify the materials beyond simply stainless steel or bronze.

 

[477stephen]

Different materials are going to require different amounts of lubrication. It's important to identify the materials beyond simply stainless steel or bronze.

sir
with the greatest of respect

Can you read the opening post as its wording may show Ive been to the SKF bearing material section

I have a choice of Sintered vast Iron Al Bronce and Mag Bronze ALL have high rates of wear

an there ain't a ton of loading in a sliding bearing valve guide

So we check the lubrication

and wot a surprise ,,,,it ain't getting any

and as I said boundary , lucky to get mixed and looking at the wear maybe full flow for 2.5th of not a lot


So I required some text m formula or a number to validate ( which was given and I have found)

Changes were made

Thank you for your input

 

[mfgenggear]

Op
Read some valve guides are cast iron which are not compatible withh stainless steel valves. Stainless steel require magnesium bronze valve guides. Steel valves can use both cast iron or magnesium bronze.

 

[TugboatEng]

I see no mention of the valve stem material.