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Bash valve longevity?

Posted by ChuckW 
Re: Bash valve longevity?
May 01, 2010 06:37PM
Hi Chuck,

The current engine uses poppet valves and lifters, if identical to the unit in Tom Kimmel's shop

Regards,

Ken
Re: Bash valve longevity?
May 07, 2010 12:00AM
1. I have no answer on White Cliffs. Perhaps we need a new topic for bash valves.
2. After 40 hours under load, I saw about 0.0005 wear on the pin and valve with thin 3/8" disks and pins of stellite. It is key to use a number of small valves instead on few big ones. Just calculate the valve opening with small lift, the loads on the valve and pin, and Bob's your uncle.
3. Balls can likewise avoid excessive load and brinelling if they are exceedingly small, but they are fiddly compared to chinese hats or disks.
4. Opening the valve with a pin and having a spring hold it open as the piston recedes for longer cutoff is pretty obvious. Having the spring position change by rotating a sleeve and to change the comression distance is what I did on the engine I sold R. A. Gibbs about 1967. Dashpots, magnets, pawls, lots of messy designs could be used. It could not run on high superheat, but ripped benches and boards up when checking torque in Pleasant Garden. Gibbs bought it solely because when run on air, the exhaust temperature was considerably higher than the inlet temperature and he did not understand why.
5. If anyone can tell me how to actually control a variable opening non contact bash valve, I will be pleased to listen attentively.

Karl Petersen
Re: Bash valve longevity?
May 07, 2010 03:52PM
Pete Barrett did three designs for the VW flat four steam conversion. The first iteration had three ball bearing bash valves in a row. The second is what I have in my collection. It is poppet valves in line with the cylinder. After a valve keeper broke and the engine swallowed a valve, making all kinds of noise and black smoke, Pete did his third design, with the poppet valves cross-wise with the cylinder head so they could not be swallowed. The advantage of bash valves is short cutoff with is very difficult to do with a conventional cam and poppet valve because of acceleration issues. Tom Kimmel
Re: Bash valve longevity?
August 22, 2011 11:42AM
This is an old thread but I wanted to thank everyone for their patience and for being such a great source of solid information...
I've continued learning and experimenting with bash valves and a limited record with a few details and videos can be found at my web site for anyone else headed down that road.

Some bash valve steam experiments-

Chuck



Edited 1 time(s). Last edit at 08/22/2011 11:51AM by ChuckW.
Re: Bash valve longevity?
August 22, 2011 11:16PM
Hey ChuckW, thanks for the link to your site. I enjoyed the videos. The 2 cyl compressor looks like it runs very well.
Re: Bash valve longevity?
August 23, 2011 06:51PM
Your welcome... there isn't much there for the experienced but perhaps it could save the newbie a few hours. I'll keep it updated as progress is made.
Any comments or suggestions based on what you see there are very much welcome.
Chuck



Edited 1 time(s). Last edit at 08/23/2011 10:19PM by ChuckW.
HLS
Re: Bash valve longevity?
August 24, 2011 08:56AM
Hi Chuck
A steel ball will never survive Use a silicon nitride ball you can get it out of a Mc Master Carr catalog.
Good luck
Harry
Re: Bash valve longevity?
August 24, 2011 05:39PM
Hi Harry,
I have the silicon nitride ball and a tungsten carbide seat to go with it... do you suppose the tungsten carbide will chip? Have you tried such a combination?
Chuck
Re: Bash valve longevity?
August 24, 2011 07:23PM
Hui Chuck,

316 SS would be a good seat against the Si3N4. It will conform and form a nice seat. The 2 hardened ceramics against each other wouldn't be my choice until someone else gave a green light.

Keith
Re: Bash valve longevity?
October 09, 2013 02:51PM
The White Cliffs thermal solar project report that was previously only available for sale now appears to be downloadable.

“By far the major part of the project time, effort, and other resources was required to establish the steam engine (especially its simple valve mechanism) and water/oil treatment systems as robust, reliable working units. The solar array, collectors, electrical and electronic control and energy generation and storage systems posed relatively few problems in design, development, checking out and establishing continuous reliable operation.”
Pg 32

[www.energy.nsw.gov.au]

Chuckw
Re: Bash valve longevity?
October 10, 2013 06:37AM
Hi ChuckW,

Interesting read. Looks like 1000-3000 hrs life for the bash valve. Maintenance interval inspect every 1000 hrs. Sad the project wasn't expanded/refined and got converted to photovoltaic in 1996. Darn photovoltaic put out 40kw vs the 25 of the thermal system. Says the plant is now decommissioned as of 2004.

Keith

P.S. That document is a monster and pretty hard to navigate. Too bad it wasn't OCR'd. I looked on the net for a better copy without success. Thanks for posting the link.



Edited 1 time(s). Last edit at 10/10/2013 06:47AM by kdc2.
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