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Marks Holt 75

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JRR

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Hi Mark
I must apologise for hijacking your thread.As soon as I find out how to remove it I will do so.
Please do not think I did deliberately.Now I know I should have start my own thread.
John
 

teeleevs

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I have been guilty of Hyjacking a thread, for that I am sorry. I am unaware of how to start my own thread for my own Twin Opposed half Scale Onan Engine
 

dnalot

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I must apologise for hijacking your thread
Accepted. I gave your post a like when you posted your photos, I said my piece and then I moved on. Time now for everyone to do the same. No hard feelings.

Mark T
 
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Cogsy

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I have started a new thread for Johns' Holt and cleaned this one up a bit. Please continue your story Mark - I've been following along and really looking forward to the completion.
 

dnalot

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With this post my build of the Holt 75 is all but completed. The reason I say “all but” two of the spark plug wire with boot I ordered are on back order. Anyway I have made all of the parts for the distributor from the last page of the drawings by George Brinell.

The mount for the distributor can be rotated to adjust the timing while the engine is running. I rather like that. I am using a CDI ignition system with a hall sensor. The magnet for the hall sensor is located at the bottom of the distributor mount. A steel disk with 4 holes is attached to the shaft that drives the distributor. As the disk turns it exposes the magnet to the hall sensor through the hole in the disk triggering a spark. The base for the distributor cap is screwed onto the distributor base. It will rotate with the base when timing is adjusted. The rotor is secured to the shaft that drives the distributor. After adjusting the hall sensor to fire number one cylinder at 15 degrees BTDC the rotor was positioned on the shaft pointing at the number one cylinders terminal on the distributor cap.

While I wait for the spark plug wire I will probably start building a base for the engine and a box to carry it in. When the the parts arrive it will be time to see if it will start. Then take some pictures and make a video.

Mark T

Hall Sensor.jpg


Sensor and timing disk.jpg


Rotor.jpg


timing disk.jpg


Cap and rotor.jpg


Completed.jpg
 

gbritnell

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Hi Mark,
I'm glad everything is back on track. As usual the parts look great. I didn't get any responses to the rain cap I posted but I'm assuming you saw it.
gbritnell
 

Richard Hed

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With this post my build of the Holt 75 is all but completed. The reason I say “all but” two of the spark plug wire with boot I ordered are on back order. Anyway I have made all of the parts for the distributor from the last page of the drawings by George Brinell.

The mount for the distributor can be rotated to adjust the timing while the engine is running. I rather like that. I am using a CDI ignition system with a hall sensor. The magnet for the hall sensor is located at the bottom of the distributor mount. A steel disk with 4 holes is attached to the shaft that drives the distributor. As the disk turns it exposes the magnet to the hall sensor through the hole in the disk triggering a spark. The base for the distributor cap is screwed onto the distributor base. It will rotate with the base when timing is adjusted. The rotor is secured to the shaft that drives the distributor. After adjusting the hall sensor to fire number one cylinder at 15 degrees BTDC the rotor was positioned on the shaft pointing at the number one cylinders terminal on the distributor cap.

While I wait for the spark plug wire I will probably start building a base for the engine and a box to carry it in. When the the parts arrive it will be time to see if it will start. Then take some pictures and make a video.

Mark T

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Will you have this running in December? I might like to see it in person.
 

dnalot

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Looking good Mark, shoot me an email at rsholl@copper.net with your shipping address. I found a pair of boot/wire assemblies to send you.
Roy Sholl
Thanks Roy. Check your email.

So while I await the plug wire I will be making the parts for the rain stop for the exhaust manifold.

This thread has had over 40,000 views, most of them are probably me but it looks like someone is watching. Thanks to everyone watching and a big thankyou to those that left a comment or two.

Mark T
 

dnalot

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So where am I at on this project. With the Thanksgiving Holiday behind me I went back to work on the Holt. Still no spark plug wires with Boot so I robed some wire off another engine and using alligator clips to hold on to Plug. Put some fuel in the tank, switched on the power and turned it over. She fired right up and then quit. Did this a number of times with lots of smoke to show for it. And a water leak on a manifold and oil leaking from the front shaft seal. Also had problems keeping the big flywheel tight to the shaft. To fix that I upped the set screw a size and added a second one. After fixing the water leak I tried to start the engine again with the same result. I rechecked my settings over and over, tried a different CDI system and still no glory. After taking to many days farting around I finally started looking at the hall switch. What I found is it worked at low RPM but not at high RPM. I have an assortment of hall switches of different makers. Some are smaller than others and it was one of those I had used. So I changed out the hall switch with the bigger one and tried again. She fires right up now and runs but the oil leak is making a big mess. I must have forgotten to install the o-ring to leak this much. I ran a tank of fuel through the motor and the smoke has nearly stopped. Compression has tripled so I think the rings have seated well and the valves are doing their job. Before I work on tuning the motor I need to strip the engine down on the front end to address the oil leak.

Mark T
 

gbritnell

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Hi Mark,
I'm glad to hear that you have it running satisfactorily. My engine doesn't have oil seals as I built it from the original drawings. When I redesigned it I added the O rings because I would get a little weeping from the crankshaft so thought it would be better with a seal. I'm guessing that it's the O ring. Also my engine has a points setup which was more complicated to make so that's why I designed the Hall setup. I use a variety of Hall sensors on my different engines and don't really seem to have issues with any of them.
 

dnalot

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I'm guessing that it's the O ring.
I have no oil escaping from the rear shaft seal so I probably forgot to install the o-ring in the front. Its not a lot of oil but it runs along the shaft to the front flywheel and gets flung out making a mess of my work bench. I'm on my way out to the shop now to see what I can do about it. I will take some completed photos once its cleaned up and reassembled. And will post a vid when it is tuned up. This has been a great project and I hate seeing it end.

While I am bringing this build to a close I am making plans to start building "Bernay's steam engine" from the plans provided by "Jorgensen Steam" that I found posted on this forum. Its an unusual design with lots of interesting moving parts. The photo below is from Free CAD Designs, Files & 3D Models | The GrabCAD Community Library . This is a nice sight offering cad drawings and there are other photos of this engine posted.

Mark T

original.jpg
 

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