Author Topic: Chris's Holly Pumping Engine Build  (Read 81066 times)

Online crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1740 on: December 03, 2021, 08:10:49 PM »

Online crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1741 on: December 04, 2021, 06:41:11 PM »
So, yesterday I got the links between the valve cranks on the IP cylinder made

and this morning made up the links from the cranks down to the eccentric followers. Then came lots of working on the timing. With the flats on BOTH sides of the valve rods this time, I did not have the binding issues, but it introduced a different wrinkle. When figuring out the timing, I had made marks on the ends of the rods so I could see the movements and know how much I was advancing/retarding the cranks, but now the starting point was TWO possible places, since there are two corners where a flat can open to the ports. When I first set the timing two of the rods were about 90 degrees out - the valve was opening and closing, but backwards to the timing.   :wallbang:   I was assuming that I could copy the relative positions from the HP cylinder and its crank to the IP cylinder. Which works, as long as the starting point is the same...

Okay, that came out very confusing in words, but that matches how confusing it was on the model!

Bottom line, I got the orientation of the valve rods sorted out by removing the exhaust valve rods, and cycling things through by hand under very low pressure, to sort out the open/close positions of the valves and eccentrics. Then put the exhaust rods back in, got them sorted out by looking through the exhaust port (glad I had not fixed the exhaust piping on that side yet).


And... it started to run!   :pinkelephant: :pinkelephant: :pinkelephant: (hmmm, does Surus get a royalty every time we use that icon? ) 

Quickly grabbed the camera:
As you can see/hear, the timing is still a little off, causing it to speed up/slow down through the cycle - at first glance the exhaust valve on the bottom end is not opening quick enough and it is back-pressuring the piston a little. Probably several things need a tweak, but that can wait till later - going to bask in the fact that it is powering on both cylinders now.
 :whoohoo:    :cartwheel:

Offline RReid

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Re: Chris's Holly Pumping Engine Build
« Reply #1742 on: December 04, 2021, 07:06:21 PM »
Congratulations Chris; that's a really big milestone! You've earned both a beer and a Christmas cookie! :DrinkPint:
Regards,
Ron

Online crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1743 on: December 04, 2021, 07:10:31 PM »
Congratulations Chris; that's a really big milestone! You've earned both a beer and a Christmas cookie! :DrinkPint:
Yum!  Hope I get another when the timing is adjusted...   :Lol:

Offline cnr6400

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Re: Chris's Holly Pumping Engine Build
« Reply #1744 on: December 04, 2021, 07:55:14 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Wow! great looking run on two pots! It may schmooth out on its' own a bit with the third pot pushing. Congratulations! Here's some virtual Navy rum for your egg nog, to go with the cookies ------->

Online Dan Rowe

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Re: Chris's Holly Pumping Engine Build
« Reply #1745 on: December 04, 2021, 09:44:30 PM »
Nice work two down then the big one. This is really exciting to watch.  :popcorn:

Cheers Dan
ShaylocoDan

Offline Admiral_dk

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Re: Chris's Holly Pumping Engine Build
« Reply #1746 on: December 04, 2021, 10:07:45 PM »
Great to see that all your amazing work pays off first time  :praise2:

Online Kim

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Re: Chris's Holly Pumping Engine Build
« Reply #1747 on: December 04, 2021, 10:46:57 PM »
Well done!  Running on 2 cylinders!  That is a big milestone  :cheers:

Kim

Online crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1748 on: December 04, 2021, 10:54:29 PM »
Thanks all! No more timing tweaks yet, doing holiday prep activities. I did look at the plan sheets for the LP cylinder, at first I thought it printed wrong, it looked too short. Just an illusion, its so much wider!


 :cheers:

Offline Craig DeShong

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Re: Chris's Holly Pumping Engine Build
« Reply #1749 on: December 05, 2021, 12:01:15 AM »
Woo Hoo!!! 

Ill drink one with you  :cheers:
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Online crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1750 on: December 05, 2021, 12:10:11 AM »
Woo Hoo!!! 

Ill drink one with you  :cheers:


Uuuurrrpppp!   :DrinkPint:

Offline Roger B

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Re: Chris's Holly Pumping Engine Build
« Reply #1751 on: December 05, 2021, 08:21:02 AM »
Splendid  :praise2:  :praise2:  :wine1:

I do like to watch all the complicated steam engine valve gear moving  :)  :)  :)
Best regards

Roger

Offline Firebird

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Re: Chris's Holly Pumping Engine Build
« Reply #1752 on: December 05, 2021, 09:01:48 AM »
Hi Chris

Superb   :praise2: :cheers:

Cheers

Rich

Offline PJPickard

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Re: Chris's Holly Pumping Engine Build
« Reply #1753 on: December 05, 2021, 12:32:13 PM »
That is really something!

Online crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1754 on: December 05, 2021, 02:53:53 PM »
Thanks guys - this morning I went back to watch it run some more (it is a bit mesmerizing) and did some tweaks on the valves. The exhaust timing turned out to be fine, it was one inlet valve on each cylinder that needed to be turned a few degrees relative to the crank arm that got it running smoother. Also, I think CNR is right about the third cylinder smoothing it out some more when it is online, As it was running I pushed/pulled on the LP crosshead at the appropriate times, and it does even out the surging more, when the other two are near the ends of thier strokes.
So, here is a new video of it running a bit better, it does run slower now, should be even more so when the LP cylinder is made.

After making the video I realized that I had not put the IP exhaust pipe assembly in place yet, have done that now, still runs the same!
So, on to the LP cylinder assembly. The larger 4" faceplate I had ordered is here and waiting to hold the LP parts (the 3" faceplate is the same size as the bore, so that one won't work). I had been thinking of making the top/bottom caps from some thick aluminum bar stock that I have, but I had the idea of taking the cored bronze that the cylinders are made from and putting a plug in the center to make a solid disk. Probably will go that route, I much prefer machining brass and bronze to aluminum (as I am sure you have noticed during this build! ).

The inlet valve on the LP is also a corliss rotary valve, but the exhaust valves are poppets, that will be a new thing for me, have not made any of those before. Should be fun!
Thanks to all those following along.   :cheers: