Haworth valve setting and Johnson Bar

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JohnR
Posts: 59
Joined: Wed Feb 19, 2003 8:08 pm
Location: Northern Ohio USA

Haworth valve setting and Johnson Bar

Post by JohnR »

I have set my valve timing have got the engine running on air on my stand.
Both forward and reverse are good.
I need to set the Johnson bar in neutral position and establish the position of the
slide block with regards to neutral.
I assume at neutral the valve linkage is in the exact middle of the slide block
and I would adjust the length of the connecting rod from the Johnson bar to match
this.
I followed Bill Perry's method to do the initial timining.
By the way this is for a Sweet William style engine.

Thank you

JohnR
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Bill Shields
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Re: Haworth valve setting and Johnson Bar

Post by Bill Shields »

Is there a question here?

seems like you have it under control...
Too many things going on to bother listing them.
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Benjamin Maggi
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Location: Albany, NY

Re: Haworth valve setting and Johnson Bar

Post by Benjamin Maggi »

John,

As it turns out, last month I timed my Sweet William chassis too. Actually, two friends did it for me and I basically watched befuddled.

viewtopic.php?p=464137#p464137
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
David Powell
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Location: Pickering Ontario Canada.

Re: Haworth valve setting and Johnson Bar

Post by David Powell »

Hackworth valve gear is a poor choice. It will" Work" but engines with it will not reach the full potential of running smoothly and powerfully in both directions at varying cutoffs. If one tries to get the best performance possible( By adjusting eccentric or return crank position and rod lengths) in one direction running in the other direction will be very poor Regards David Powell.
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Benjamin Maggi
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Re: Haworth valve setting and Johnson Bar

Post by Benjamin Maggi »

I am quite content with not reaching the full potential running in reverse at various cut-offs. Running well in forward is perfectly acceptable to me.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
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Bill Shields
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Re: Haworth valve setting and Johnson Bar

Post by Bill Shields »

Also be aware that valve events are changed by the vertical position of the drive axle as opposed to 'design position'.

Southern valve gear has a similar problem.

Things like how much water do you have on board can affect valve events
.
I have seen variations of the model with the back axle fixed vertically to handle this situation.

Does not seem to keep them from running like crazy though
Too many things going on to bother listing them.
Pontiacguy1
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Location: Tennessee, USA

Re: Haworth valve setting and Johnson Bar

Post by Pontiacguy1 »

valve events are changed by the vertical position of the drive axle
That's why the main axle in most of these locomotives isn't sprung, it has a piece of rubber, hard plastic, or something over the axle box so that it has very little vertical movement. At least that's what I've seen that has been done on several locomotives that I have witnessed running using the hackworth gear. They all ran fine. They bobbed and danced a little bit going down the track, but I don't remember any derailment issues with them, even on rough track. And they were pulling several cars and some passengers and having a good time doing it.

Yes, Hackworth gear isn't a perfect gear, and it has some flaws. Not everyone cares about that. It will run your locomotive well, and hopefully you'll have a lot of fun. It's main benefit is the abject simplicity of the design with relatively few parts to have to make. Yes, wear of the blocks can be a long-term issue too. Again, simplicity is the major benefit. Everything in life is a trade-off.
skyloop440
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Re: Haworth valve setting and Johnson Bar

Post by skyloop440 »

I think Pontiacguy1 hit the nail on the head here. The Wendy I'm building has hard rubber in the journal boxes on the rear axle to stop movement. The key to this hobby should be to have some fun and enjoy what you have built. There is nothing wrong with rivet counting if that's your thing but. I have built Walschaert, Stevens and Baker valve gear, Hackworth sounded pretty good to me.
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