Stuart No 4 Steam Passages

[Alan Worland 1Participant @alanworland1]

I started to clean up the cylinder on the No 4 today and noticed that the steam ports on the valve cheat face are slightly out of square.

Not a major problem I thought till I put a vernier across the width of the opening and found it was slightly over 1/8 so if I put a cutter in the slots to square them up they will get larger than the specified 1/8 wide!

They would probably end up at 0.15 – 0.16 wide

My question is would this be a problem and should I compensate for this in the slide valve?

[Alan Worland 1Participant @alanworland1]

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Cast in ports are seldom quite right so to avoid a lot of extra work I suggest that you leave them as they are . If you start altering one thing in a a valve/valvegear set up you will end up altering everything and a usually only for small advantage in the end . 

[Alan Worland 1Participant @alanworland1]

Surely a ‘wonky’ steam passage will result in strange timing? and more importantly – not a very good exhaust!

[Ramon WilsonParticipant @ramonwilson3]

Alan, do you have enough metal to cut out a pocket say 2-3mm deep and lay in an insert (another use for JB Weld too)

You can either pre mill the ports before fitting or do so after. Let the whole lot set a good day or so before taking a skim across to clean up.

 

JB Weld will certainly stand up to steam in that application – it did in my Twin Victoria for many years, on  steam, without a hitch and of course if you only run on air then it wont matter at all. The out line of the insert/pocket  can be such that it sits just under the inside lines of the steam chest which in itself will provide security.

 

Hope thats of help – Ramon

[Alan Worland 1Participant @alanworland1]

Now thats an idea!

I was thinking more along the lines of modifying the slide valve to accomodate the new dimensions of the steam ports?

Talking of JB Weld, I picked up one the other day but found it is ‘Kwik’ which has about 4 minutes working life, cures in 30 mins, and is only any good to 150 C – its going back in the morning!

[John OlsenParticipant @johnolsen79199]

Hi Alan, I would suggest just tweaking the valve a little to match the ports. The cavity on the inside should just span the inside edges of the two outside ports. The outside should be the same as the overall dimension across the ports, plus the lap, which you should be able to work out from the specs. So you can match the valve to the ports as they are, which will give an angled end, or you can ease the ports a little to be square, then match the valve to that. I would do the latter.

 

regards

John

[JasonBModerator @jasonb]

If you do end up going for a new valve port face then have a look at the link I posted in this thread which shows one being done

 

J

[Ramon WilsonParticipant @ramonwilson3]

Yes I should have warned you about that Alan, the rapid version has nowhere near the temperature tolerance – the standard type is definitely what’s required.

 

John, by fitting a plate like this when this sort of situation arises the ports, as well as their position on the port face and the slide valve can be made exactly to print without compromise .  The product certainly stands up to ‘dry steam’ though what degree of superheated steam it would tolerate remains to be ascertained.

 

Perhaps I should add this Alan  – once its in you’ll have to mill it should you want to get it out again

 

Ramon

 

Edited By Ramon Wilson on 16/01/2011 19:25:48

[Alan Worland 1Participant @alanworland1]

Thanks for your help and advice!

I think I shall aim for producing a revised slide valve to suit the ‘to be machined ports’, then if it all goes wrong – I can let a bit in!

Nothing like a plan!

[V8EngParticipant @v8eng]

I have looked at the JB Weld website but am not clear as to which product  is being referred to as standard here.

 

Can somebody tell me?

 

Thank you.

[JasonBModerator @jasonb]

This one you can get it on e-bay for about a fiver

 

Jason

[V8EngParticipant @v8eng]

Jason.

Thanks the link certainly made it clear, I will get some it sounds useful stuff.

 

Originally I had done a search and been guided to their uk site, which did not seem to mention a standard product.

[TerrydParticipant @terryd72465]

Alan,

 

would it not also be possible to solder in a plate after cutting out the pocket using soft solder such as 60/40 (electrical solder) with a melting point of around 190degrees C.  Just preflux with a good plumbers flux. wrap a small serpent of fine solder wire below the plate infill, and heat gently until solder emerges from the seams.  Newer lead free solders also have even higher working temperatures but are not necessarily eutectic and are a bit more difficult to work with, but others are.

 

Soft solder is very underestimated and underused these days given modern adhesives, but it has advantages and has been proven to be able to last for centuries.  Not sure about the lasting qualities of resins and other polymeric adhesives.  I’m not up to date with developments in the Auto industry now, but does anyone know if radiators are still soldered in the traditional way or can the newer resins be used to bond the parts as they have such high pressures and temps to work with?

 

You obviously make your own choices but look at all the alternatives and their consequences.

 

Best regards

 

Terry

Edited By Terryd on 16/01/2011 22:44:59

[CHRIS WOODS 1Participant @chriswoods1]

Just leave it alone it’ll work just fine – mine did.  Why create problems for yourself?

[Alan Worland 1Participant @alanworland1]

Terry

Thanks for that, although machining out a pocket for new timing ports will be my last resort.

I have never tried soldering CI having always considered it ‘too black’ with carbon.

Re radiators – cant say I have seen a proper radiator for a long while, they are all plastic and aluminium these days and ‘crimped’ together with gaskets in!

Not like my old Morris Minor! where you have some hope of repairing it!

 

Alan

[TerrydParticipant @terryd72465]

Hi Alan,

 

I’ve never tried it either but it is possible that modern more active fluxes could allow the ‘wetting’ process to start and after that it’s a doddle.  My new workshop is coming along nicely and I think that I’ll test the process when it is finished. 

 

As others have said it may just be better to leave your steam chest ‘as is’ and accept the errors.  But it’s fun philosophising about the possibilities and the debate may help others in different circumstances and different problems.

 

Best regards.

 

Terry

Edited By Terryd on 17/01/2011 14:27:16

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