Brian builds a Corliss

[brian Rupnow]

The two hours of "running in" is over , and after cleaning up all the lubricating oil, the engine turns as smooth as silk. Something has gone awry with my Solidworks, and I seem to have lost the capability to print gaskets off at 1:1 scale. This is a fairly big deal, as this engine has a lot of gaskets. I don't even have a drafting board and machine to hand draw the gaskets right now, so tomorrow I will try doing a re-install to see if that clears up the problem.

[brian Rupnow]

This morning I put a saw cut in the rear (non-linkage) end of the four valves, and scratched an "x" on the side which corresponds with the cut away section at the center of each valve. I messed around for what seemed like a very long time with the linkages and the main "wobble plate" which pivots on the center of the cylinder, to get them freed up and operating while I turned the flywheel. I have been studying Arnolds build thread on Model Engine Machinist, and Captain Jerry posted a set of directions for timing this engine (Reply #305) that reads as follows:#1--Set crank to horizontal, either at tdc or bdc.--Yep, I understand that. #2-Set eccentric 90 degrees to crank (Hi point up)--Yep, understand that too. #3-set main wobble plate on side of cylinder to vertical--Got that too. The last direction reads "Adjust each valve so the valve edge is at the edge of it's respective port", and I don't understand that. Can someone please do quick a quick sketch of the four valves in this condition showing me what position each cut away section of each valve will be?---thanks, --Brian

[aostling]

. . . The last direction reads "Adjust each valve so the valve edge is at the edge of it's respective port", and I don't understand that. Can someone please do quick a quick sketch of the four valves in this condition showing me what position each cut away section of each valve will be?---thanks, --Brian

Are these not cylindrical rotary valves, turning in a cylindrical bore? If so, I'd guess you would adjust the valve so that its edge is just at the angle when it will open (i.e. uncover the port).

[brian Rupnow]

Well, no good news to report. I never did get my cad system to print 1:1 templates to make gaskets. A friend with the same system as I have will print 1:1 templates for me this week. I have not been able to get the engine to run in it's current state with no gaskets, too many air leaks. I didn't have a correct size o-ring for the piston, but for the moment have stretched a 1" o-ring over my 1 1/8" piston----this is never a good idea, but sometimes you just work with what you've got. I have dismantled the cylinder and cross-head assembly from the base and flywheel and when I get gaskets made I will adjust the valves until moving the wobble-plate from side to side make the piston and rod travel back and forth. I may remove the packing gland as well until I get things sorted. Reassembly of all parts is not a big deal----takes about 15 minutes. Our snow is almost gone from the front and back yard and one more day above freezing should get rid of the last of it. Yesterday the biggest fox I have seen in my life walked down the side of our lot. We've been here 22 years now, and have seen almost every kind of Ontario animal in our yard except for a bear and a moose.---And yes, aostling, they are and you are correct.

[brian Rupnow]

Oh!!!--Be still, my racing heart!!!--it works. Not the engine itself yet, but with a full compliment of necessary gaskets, I can make the piston move back and forth in the cylinder by moving that front wobble plate back and forth. Oh Joy!!!

[brian Rupnow]

It's a great day in Barrie!!! My Corliss engine ran today for it's very first time. I have a lot of adjustments and tweaks to do before this engine is running as good as some I have seen on the internet, but it makes my heart sing to see the engine setting there huffing away. I am very, very pleased with this and a big thank you to all the folks on the forum who offered advice or help while the project was being machined and put together. I still have cosmetic work to do, and a base to be built, but this first milestone is met and I can't get the smile off my face.---Brian

https://www.youtube.com/watch?v=NCl0flMy2iA

[DrMike]

Good for you, Brian, it's a good day indeed!
Tweaking a Corliss steam engine to its potential is a task given to only a few lucky folks, and probably never me... so please, make the best of it.

[olf20]

Great job! It makes me feel just about as good as you feel. I love all the mechanical
motion.
olf20 / Bob

[PStechPaul]

It is indeed a fascinating mechanical contrivance.

Do such engines usually have that "lope" or is that something to be tuned out?

[fjk]

!

(sorry I’m not as eloquent as the others)

[brian Rupnow]

A few things I've discovered along the way--The brass bushings that the valve extensions run thru, on the linkage side, do need o-rings and gaskets. They are reamed to an exact fit on the valve extensions, but if you tighten down the bolts holding them to the cylinder they bind badly and the valves don't want to turn. If you leave them loose so as not to bind the valves, then a lot of air escapes around them. I think that the fix here is to open up the bushing bore by 0.005" or 0.006", and counterbore the side closest to the cylinder to accept a 1/8" i.d. rubber o-ring, to a depth that puts about 20% "squeeze" on the o-rings when the bolts are tightened to prevent air leaks. The brass cover plates on the other side of the cylinder do need gaskets under them. The lever arms which clamp to the valve extensions use a #2-56 bolt to tighten them in place. Great in theory, but they slip--and if you tighten them enough that they don't slip, then it soon strips the thread in one side of the slit that the bolt tightens into.--Learning as I go here, but these are what showed up as I fettled the engine this afternoon. And Paul--It shouldn't have that "lope". I think that can be tuned out.

[haroldmulder]

Great Job Brian nice to see that engine just motoring along.

Harold

[aostling]

. . . I think that the fix here is . . . a 1/8" i.d. rubber o-ring . . .

Would this fix preclude running on steam?

[RB211]

Would this fix preclude running on steam?

A steam engine that actually runs on steam??

[brian Rupnow]

I don't think it would preclude the engine from running on steam.-However, if I planned to run it on steam I would use o-rings made of Viton. That is an o-ring material not affected by heat.---Brian