HEEELLLPP how much oil does me valve guide need

[Brian d marge]

you are not going to believe this, but a simple problem has turned in a " bigger problem"


I have an old Royal Enfield Rocker ( yup the same one STILL going) feed pump has seen better days, output at 3000 RPM about 50cc and remember that goes through the rocker blocks, So I want to determine " How much oil me valve guides needed" a simple ( sliding) bearing calculation ...i reach for machineys handbook nothing I google ,,,, ( im not joking) nothing every other engineering book I have ,,,nothing NOTHING on axil sliding bearings, Valve guides, I found a possible contender, Q( flow ) for Thrust bearings but then we need a pressure ,,, Enfield , pressure ? not in the same sentence , enfields are a quantity flow

anyone OUT THERE in the internet land an Engineer, maybe not a machinist , someone who can crunch numbers on valve guides or has a book on Guide , slipper bearing design or just how much oil does the damn thing need 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?) How much oil does the exhaust valve need to have full roughness coverage mid stroke

I thought it would have been a simple question stupid me thought google could help



Thanks in advance Stephen

[Grumph]

Like you, I've never seen a figure. But a lot depends on materials. Iron or bronze ? Is the valve a stainless replacement ?

In these old aircooleds polishing the valve stem does help as often it's not as well finished as it should be.

I've had acceptable life from a phosphor bronze guide and polished stainless valve. Iron guides not so much.

Always wanted to try a guide made from the modern sintered iron/bronze mix used in most modern motors
but never been able to source the materials. That stuff is hard and seems to need very little lube.

[Brian d marge]

Like you, I've never seen a figure. But a lot depends on materials. Iron or bronze ? Is the valve a stainless replacement ?

In these old aircooleds polishing the valve stem does help as often it's not as well finished as it should be.

I've had acceptable life from a phosphor bronze guide and polished stainless valve. Iron guides not so much.

Always wanted to try a guide made from the modern sintered iron/bronze mix used in most modern motors
but never been able to source the materials. That stuff is hard and seems to need very little lube.

I know ! I thought it would be a "simple " job

I made the mistake of posting on an " engineers forum" https://www.eng-tips.com/viewthread.cfm?qid=522339 ( engineers my arse )

I have some info of valve guide design if you are interested

I mean its just a simple sliding bearing of plane motion EVEN the Egyptians used the damn things! I could model it as a thrust bearing , but then I would need a pressure ..... Enfields and pressure are rarely used in the same sentence

I might try valve guide manufactures and see what turns up


Stephen

[Grumph]

Rocker geometry was mentioned on that forum . Which reminded me that I was asked to have a look at the ex Bob Harris 350 valve gear.

To use better springs needed longer valves which meant spacing the rockers up.....
As you'd imagine the geometry was wellfucked.
I made some recommendations which seem to have helped so I'm told.

I'd think it may be worth going back to basics and getting the rocker @90degrees to the valve at mid lift.

If you don't want to run stem seals chamfering the top of the guide to a sharp edge works almost as well.

[pete376403]

The worst valve guide wear I have ever seen was an XJ6 Jaguar, DOHC with buckets pushing straight down on the valves. Seals were dead hard so nothing stoping the oil going down the stems

[Grumph]

The worst valve guide wear I have ever seen was an XJ6 Jaguar, DOHC with buckets pushing straight down on the valves. Seals were dead hard so nothing stoping the oil going down the stems

The more common problem with Jags is lack of use. Parked up the valves stick/corrode to the iron guides.
Those stuck open get smacked by the piston and bent.

Speaking as the past owner of two Mk2's

[Brian d marge]

Rocker geometry was mentioned on that forum . Which reminded me that I was asked to have a look at the ex Bob Harris 350 valve gear.

To use better springs needed longer valves which meant spacing the rockers up.....
As you'd imagine the geometry was wellfucked.
I made some recommendations which seem to have helped so I'm told.

I'd think it may be worth going back to basics and getting the rocker @90degrees to the valve at mid lift.

If you don't want to run stem seals chamfering the top of the guide to a sharp edge works almost as well.

Strangely my geometry is kida ok ( for an enfield ) the rocker tip wear is 3 mm and central My race bike has seals but m daily driver hasnt

Its suppy or lack of is the problem

but u cant just install a larger pump as it kills the oil drive gear ( ask me how I know) You have to open up All the passages to the rocker block

[husaberg]

I am no engineer

[Grumph]

I've had a few race bikes from the Cust era through the workshop.
A Velo,Triumph and Rudge. All had supplementary oil feeds direct in to the exposed guides.

Given the dusty conditions I suppose it was worth doing.

[husaberg]

I've had a few race bikes from the Cust era through the workshop.
A Velo,Triumph and Rudge. All had supplementary oil feeds direct in to the exposed guides.

Given the dusty conditions I suppose it was worth doing.

Pretty sure Burt's Indian was either oil can or greased nippled for the rockers
I know he used AJS rockers.
Okay grease nipples.
to be fair though he only had splash and hand pump lubrication to the big end until the mid sixties if not later...



I did find this.
https://forums.aaca.org/topic/118565...-valve-adjust/
https://www.smokstak.com/forum/threa...-engine.88359/

As modern engine have seals I would say modern ones only get lubed from the fuel.
They rely on decent and matching materials.
that said in a Ohc engine there is sht tons of oil in the head where as in a OHV they tend to rely on mist for the rockers etc.

this would be in keeping with the era
https://www.aliexpress.com/item/1005...UaAl2LEALw_wcB

or a steatlh set up with a two stroke autolube
KTM have a electric pump on the eTPI bikes

but this is even cooler

[Brian d marge]

Im thinking along these lines

or a simple drilling in the rocker-block to aim an oil stream at the guide

After I address the oil pump

[husaberg]

https://www.ebay.com/itm/166782220617
https://forum.classicmotorworks.com/...?topic=24157.0

Results are in : 28 psi at idle...1100 rpm's....... 65 psi on the nose at 2500 rpm's..... 70 psi and still going at 3000 rpms ! WhoOoff that's some good oil pressure. That's enough to keep your lifter's pumped and float the bearings !

[F5 Dave]

What's a ' Valve Guide?
I guess my van has them. Under the seat then. Well, passenger seat.

[Brian d marge]

https://www.ebay.com/itm/166782220617
https://forum.classicmotorworks.com/...?topic=24157.0

yup them those new EFI engines same "design " just "done properly "

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)

which seems to be supported by the above video except he got more dead dinosaurs floating around than I ( bastrd hahaha) 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 upgraded 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" As you can see fk all magnitude is a quantity game here

Stephen

[Brian d marge]

What's a ' Valve Guide?
I guess my van has them. Under the seat then. Well, passenger seat.

Im struggling here