|Larry Granger||11/04/2021 19:50:37|
|1 forum posts|
Back in 2000 I purchased a Winson kit for a Pug 0-4-0 as a project for retirement. Now that I have retried and have commenced building, I find that I cannot set the valve events. I have followed the instruction religiously but find that the valves do not open enough to clear the ports in the cylinder block. Has anyone else come across this problem and in so can they offer some advice please.
During the build so far I have come across a number of problems with the quality of the parts for example an eccentric that 'wobbled' from side to side because the hole for the axle hadn't been drilled at right angles to the eccentric blank. Is it possible that the dimples in the axles for the grub screw that locate the eccentrics have not been drilled in the right place relative to the driving wheels ?
|Neil Wyatt||11/04/2021 23:58:40|
18585 forum posts
Welcome to the forum.
I think it's fair to say the Winson kits of that era have something of a reputation for needing fettling to achieve good running.
Someone with experience of this kit should be along soon.
|Paul Kemp||12/04/2021 00:36:56|
|626 forum posts|
Are you saying the valve won't expose the whole port or that it doesn't expose the port at all? If the former as long as the port is uncovered about 50% and the port openings are almost equal at both ends of the stroke it should run. If the port is not being exposed at all then you have a problem. I did do some work on a Winson Pug but only after someone else got it running so didn't have any involvement with the valve gear. I did however have a Ruston Procter TE kit that was pretty awful in the valve events department, the crankshaft had flats milled on it to locate the eccentrics and they were way off! So I wouldn't automatically trust the dimples in the axles are in the right places! If you use masking tape to pencil marks on one of the drivers each side and mark against some reference point fixed or clamped to the frames the front and back dead centre of the piston you can then see when the valves are opening and closing relative to piston movement and make any required adjustments to eccentric position if they are wrong. It's pretty simple albeit a bit of a fiddle but takes a little bit of getting your head round what is actually happening versus what should happen!
|Clive Foster||12/04/2021 09:17:32|
|2675 forum posts|
Prepare yourself for some quality computer time!
Plenty of ways to get valve gear wrong so its risky to assume that eccentric position is the only error.
Far better to sit down and measure valve movement so it can be plotted against eccentric rotation so you know whats going on. I'd be inclined to add little pictures of what the valve position looks like and how it relates to the ports at various positions too. Best to check what effects varying the cut off has too.
A boat load of boring work but, once done, you can check it against the books and/or a simulation program before coming back onto the forum armed with relevant questions hard rooted in reality. Hopefully by then you will also have some idea of what you might try to fix it so it will be much easier to follow expert guidance.
"Yep that should work well enough but while you are at it its just as easy to do .... which will turn out better overall." type advice is much easier to follow than painting by numbers in a conceptual vacuum.
Given the known variabilities of Winson kits it would be unwise to assume that a fellow suffers advice "I fixed mine by .... " is directly applicable to yours without thoroughly checking.
That said "I fixed mine by .... . Which wasn't too hard really once I'd figured it out." is a very encouraging sentiment when you fear you've ended up with an (expensive) un-fixable lemon. Even if you end up doing something different.
Best of luck.
|duncan webster||12/04/2021 22:01:08|
3178 forum posts
First thing I'd do is get a copy of Don Ashton's book on Stephenson's. I had one once but I lent it to someone and I've forgotten who. Start with Don Ashton Website
Then you need a good mirror on a stick so you can see what is going on with eth valve chest covers removed
The issue is complicated by the use of loco links, chap in our club worked out what angular relationship should be and pinned them together. This made setting them on the axle a lot easier
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