Reconditioning a Stuart Simplex

[redhouseluv]

This will be my 3rd Stuart restoration project, but this ones a keeper........ it's bruised, it's battered and in need of love and attention, however, I may not be able to do it justice atm without workshop facilities........let's see

I never realised how small one of these simplex engines was until it arrived; very cute. It turns over smoothly and I can feel sucking and blowing which is a good sign, but clearly has several issues which need to be addressed

The engine was mounted in order to power a boat, hence the angle. I took it off the base to understand what is out of alignment; just about everything is the answer! 

1. Valve chest cover is larger than valve chest
2. Valve chest top slopes downward from cylinder
3. Valve chest sides taper inwards towards valve chest cover
4. Cylinder base cover/mount looks like someone has gone crazy with a file
5. Eccentric has no bolts appearing from the bottom
6. Small hole in the cylinder base cover/mount
7. Solder between the cylinder and valve chest underneath
7. The inlet valve has been soldered in an 'interesting' way to the valve chest cover

I don't want to replace/correct everything which isn't right - it'll end up being a different engine, so I'm thinking of:

- Making a new valve chest cover which fits the valve chest (maybe a problem as the studs probably go all the way back into the cylinder)
- Maybe a new valve chest if the holes are too misaligned
- Maybe having the inlet coming through the side or top of the valve chest
- Replacing the cylinder bolts with studs/nuts
- Tidying up the Cylinder base cover/mount
- Bolts/studs for the eccentric
- Lagging around the cylinder
- Strip down, cleanup and repaint

Also, is there anyone out there who knows about these little engines:

- Why is it called a Simplex? When I Googled it I got back Simplex Locomotives? What's the connection, if any?
- I'm not sure what sort of lubricator is on it, but I kinda like it 
- From what I have read and from the type of crosshead guide this is an earlier model?
- If this came only as a kit or complete what has happened to the poor thing over the last 100 years!
- Slim chance, given the point above, has anyone got a diagram/ drawing?

[Jasonb]

Looks like quite a bit has been soldered together in an attempt to seal uneven surfaces and also the problem of holes coming out the side of the valve chest. May even be due to stripped out threads so it can't be screwed together.

Chest cover looks a different colour so possibly replaced with brass at some time, the boss being soldered on suggests the person did not have  a lathe and just soldered on what they had.

It is an early version without the trunk guide but not sure if the round rod came before or after the flat guide. Not seen one with the mounting lugs on the sole plate, they all seem to have holes passing right through

I looked at a lot when I built my replica but was not able to find a drawing, I'll did out some photos with sizes on them.

[redhouseluv]

Thanks Jason, most appreciated.

I think you're right about the valve chest and I'm now thinking about undertaking a more comprehensive rebuild when I have my workshop back. I think the solder between the valve chest and cylinder has been place there as the stud has come through at the incorrect angle into the cylinder ....... I will check when dismantling

I have been told the AJ Reeves Trojan engine designed by Edgar Westbury is a close relation (see picture). I've done a quick measure up and think I could use the steam chest and cover from this engine and machine it to size. I will have to either fill the existing holes in the cylinder or make some new ones in a different position

[Zephyrin]

A pretty little engine,
on the second picture, the steam chest looks to be too small in height, and alas the top of the cylinder has been filed to cope, this sloping side would require to be amended either by adding metal or resurfacing the top of the cylinder if the top of the piston allows.

I hope that putting all the parts apart will not be too difficult owing to the bruised screw slots, and the soft solder in many places.

And the tap on the steam chest cover should not be after the oiler, but before.

 

[redhouseluv]

I agree with your assessment and the tap is definitley in the wrong place.

Regarding the sloping of the cylinder, the adding metal option is my current thinking. I would first make and fit a new steam chest and cover, the gap could then be seen and filled accordingly.

Its difficult to work out what to do and what to leave when restoring an engine of this age. I want to make it look good, function correctly, but without creating a 'Frankenstein' engine? 

[Jasonb]

lot of work to make a good one like these.

Probably a job saved until you have the workshop up and running again a smaking new parts and repairing old threads etc is not really  a kitchen table job.

Don't forget it is likely to have Whitworth threads and not BA due to it's age.

[Bruno Mueller]

My Trojan with slip excentre.

[redhouseluv]

All the engines posted above look amazing, and yes, I will need a workshop for even the basic restoration

Started strip down today and this has definitely been built on a kitchen table and by the looks of things using kitchen utensils 

I am no expert, but having built a few engines now, I can tell when something is not right and this is like opening Pandora's box - look at the pictures

Additionally:

No gaskets
No packing in any of the glands
Stirpped threads
The eccentric strap is too big
Conrod holes look all over the show
Solder all over the place
Base plate hacked with a file and not symmetrical
And my personal, the cylinder ports 

Its a strange one, as I really don't know where I want to get to with this engine. I think I want to the get the obvious visual things sorted out and I want the engine to have the basics to function correctly, but do I want to machine every component again .........not really. I might as well start from scratch and get it right?

[crueby]

You may be right, just take measurements, fixing them, and make a new one from bar stock if thats in your wheelhouse. Put this one back together for a comparison next to it!

[redhouseluv]

And here are the offending parts in their full glory; the valve chest and cylinder after being separated by use of a blowtorch. I managed to get some studs out and others snapped in situ, but that was going to happen.

My current thinking is to fill in the holes and then:

1. Make a new valve chest & cover but use 4 x smaller studs and nuts (8BA) so the nuts don't extend past the cover as before

OR deviating from the original

2. Make a new valve chest & cover but use 8 x smaller studs and nuts (8BA) (see black dots on cylinder)

The only reason for option 2 is there is a stud snapped off in one of the cylinder holes and I've never had much success tapping into JB Weld

Smaller studs would also allow me to move the position of the holes inward............ anyway lot's to think about, but I don't want to end up with 'Triggers broom'!

For those unfamiliar with the term, its from an 80's British sitcom and a scene where 'Trigger claims that he's had his road sweeper's broom for 20 years. But then he adds that the broom has had 17 new heads and 14 new handles' '

'How is it still the same broom' comes the reply'

 


P.S. Jason I think may be correct about the threads, however, it may just be luck, but 6BA fits perfect into the cylinder?

[Mike R]

I personally like option 2 as I'm not a purist and wouldn't know that its not original to the design, I think it would look more "scale" with 8 studs.
It is also going to be easier to repair as you say.

[Jasonb]

I think 8 fixings is overkill for such a small engine, scale does not really come into it as these are 1:1 engines designed for powering pond boats not an attempt to replicate a larger prototype.

One option to keep it looking more original and avoid the old holes would be to use 4 fixings for chest to cylinder placed slightly down and up from what is there now but use CSK screws to retain the chest to the cylinder. Then also tap the 4 corners of the chest for studs to take the cover. That way you are tapping into virgin metal in the cylinder but from the outside it will look like the studs are in the right position.

If you do want to make  a replica at least you have something to measure and they are not too hard to make.

[Zephyrin]

wow, this cylinder is in poor condition...
for me, I'll drill the screw holes, and press in a bronze rod soft soldered,  then after a pass under the milling machine to get a nice surface, I'll add a layer of bronze to the top of the cylinder, tin soldered too; then resurface the top of the cylinder and the distribution face.
steam ports need attention too, and this will lead to a new steam valve adapted to the new ports sizes. Yes, it is close to "le couteau de Jeannot", whose either handle or blade are sometimes changed, but always remains Jeannot's Knife.

a new steam chest with thicker sides must be done too with 4 fixing bolts.

[redhouseluv]

I like the idea of retaining the look and at the same time ensuring the cylinder is retained solidly - thank you for all your ideas, this why this forum is great!

@Zephyrin - I like the fact that there's an equivalent to 'Triggers Broom'!


Look what just arrived in the post - a valve chest and cover for Trojan; after a quick glance, I think they'll work out okay ...... hopefully

[redhouseluv]

Started cylinder repair:

- Filled in old stud holes
- Built up sloping edge so its now level with top of cylinder
- Filled in where studs had broken through edge of cylinder

[redhouseluv]

I have altered the base to look more like the original by:

- Removing the lugs
- Drilling 3 holes in the locations where the base is usually mounted
- Soldering 3 washers over the holes to produce 'risers'
- Filling in the uneven edges with JB Weld
- Some primer and top coats

1st 2 steps were done with a Dremel with a disc cutter and finished off with a grinding attachment. Also had fun by blistering the kitchen work surface with a blowtorch (VERY loud band!) Lucky I was forgiven as we are having a new kitchen put in 

[redhouseluv]

First adventure with a router attachment for a Dremel

Hmmm......a bit rickety and feels like it could break, however, the results haven't been too bad so far.............

[redhouseluv]

I have got as far as I can go without the use of some bigger machinery; still left to do:

- new 1/4" diameter columns
- new valve chest
- new valve chest cover
- drill new holes in cylinder
- lick of paint

Can't wait to see how this finally looks and runs ...........be right back!

[redhouseluv]

It's been 10 months since I packed up my workshop and I'm finally back in action and trying to remember all that I had learnt in the previous year!

I'm continuing with this very old Stuart Simplex, trying to make it look and work how it should. I have machined the new valve chest and cover using castings from a Reeves Trojan. I'm using the design provided by Jason all those months ago and so far so good. Just need to make the four CSK holes in the chest and attach it to the old cylinder via some new holes.

Good to be back!!

[redhouseluv]

Made progress today and the cylinder is now attached to the valve chest; nearly messed up one of the holes by using the clearance size instead of the tapping size bit, just managed to recover it - phew

Annoying, that the casting has a blow hole in it and destiny determined it would be the visible side up ....... of course. Will try and fill it using epoxy and brass powder which has kinda work before

[redhouseluv]

Help needed please!

 
I'm struggling with the thread size and type for valve rod gland. The nearest thread gauge I can get to fit is a UNC/UNF is 24 (see pic) although not certain its a good fit. None of the Whitworth or Metric gauges fit

The diameter is 0.233 - 0.234

I'm not good with threads, and given the age of this engine, what else could this be? I need to tap a new hole for the valve rod gland

Thanks

[Jasonb]

0BA is 25.4 tpi and OD is 0.236. If you have a metric gauge try 1.0mm pitch against it

If you are going to make a new gland then I would go with something finer 32 or 40tpi and maybe 7/32"

[redhouseluv]

Thanks, I'll try the 0BA on a piece of scrap and test the original gland. If it doesn't fit I'll make a new gland and tap a new hole to same size

[redhouseluv]

0BA works a treat, thanks ....... I just need to order a 0 BA bottom tap 

[redhouseluv]

I made some new columns today, which I think look more akin to the originals than the strange thin tapered ones it arrived with

[redhouseluv]

I worked on the cylinder lagging today, but this time made a template before hacking into the actual aluminium sheet and messing it up!

I was looking for a suitable template material when I came across Titanium Thin Plate Sheet Foil on the Amazon and thought I'd give it a go; it's really good and really cheap, £6.99 for a roll which will last me forever!

Result was good, just need some domed BA bolts to fix the newly cut lagging to the cylinder

[crueby]

Interesting looking material! Any difficulties or tricks needed when drilling and cutting it?  Which thickness did you get?

[redhouseluv]

I got the 0.1mm thickness

I marked it using blueing and a scribe, cut it using a pair of good scissors and then started the holes with spot drill. Its sharp BTW, watch your fingers on the cut edges!

[redhouseluv]

The template worked very well as can be seen from the photos - I will definitely be doing that again when trying to fit lagging to a cylinder.

All parts are now ready for assembly; I took this apart in Feb so should be fun trying to get it back together! Luckily I took lots of pics and made some notes which I'm trying to decipher........

[redhouseluv]

Timing trouble

I've been messing around with the timing for hours and can't get the engine to run; seems close but no cigar! The engine turns over silky smooth when not under power then tightens up on TDC and BDC with the air.

I know the cylinder ports are rubbish, basically 4 holes (see pic), but was nervous about drilling them out in case I damaged something. Should I bite the bullet and make some proper inlet and exhaust slots or is there something else I can do re. getting the timing right?

What size should the slide valve and recess be in relation to the ports?

https://youtube.com/shorts/e3C1ofwbBTk?feature=share

[crueby]

Ouch - those ports are a nasty!  They will open/close when the edges of the valve slider reaches the widest part of the opening, which is probably way off, explaining why it locks up since its likely sending air to both ends of the cylinder at once.


One thing you could do would be to make a thin valve plate with proper openings, but it requires sealing the plate to the port face thats there without leaking between the ports. Could be sealed with some gasket goop, if the plate was as large as the entire face so the studs on the steam chest help squeeze it down.


Other way would be to see if you can remake the slider to take into account the wide openings where the holes are in the slots. All depends what the diameter of the holes are, spacings, and what the eccentric travel is.

[redhouseluv]

It's working!!!!

It wasn't the timing exactly, it was the amount of the port which is exposed either end of the stroke; a couple of turns on the valve rod and she burst into life! 

https://youtube.com/shorts/mFfufzx2hNA?feature=share

[redhouseluv]

Ouch - those ports are a nasty!  They will open/close when the edges of the valve slider reaches the widest part of the opening, which is probably way off, explaining why it locks up since its likely sending air to both ends of the cylinder at once.

I think that was the problem and adjusting the valve rod must have corrected that, somehow??

[crueby]

Wonderful!! 

[Admiral_dk]

Congratulations - you got a Runner and a fine looking one too 

Per   

[Michael S.]

A great success.  I congratulate.
The wooden base also looks very nice.

Michael

[Jasonb]

Good to see it back to life.

[redhouseluv]

Thank you all your kind comments; they mean a great deal and are very encouraging ......... now onto a new project!!!