Marks Holt 75

[gbritnell]

Hi Mark,
I'm really anxious to see your engine completed! Your work has been outstanding! Of the drawing sets I've sold your's will be the first completed that I know of. As I sold the drawings I would get feedback about a missing dimension or feature that needed a little more explanation so the drawings were always in a state of updating. I'm very happy that you had good success using them. I have never had trouble with my one-way bearing setup but I like what you have done with yours. With your permission I could add your design idea to the drawing set.
gbritnell

 

[dnalot]

I have never had trouble with my one-way bearing setup but I like what you have done with yours. With your permission I could add your design idea to the drawing set.

Go for it George. Another small item to fix on your drawings is a set screw for the distributor mount. While we are on the subject I have a question about the timing disk. The drawing calls out steel as the material. I am wondering if steel being magnetic is not the best choice in breaking the magnets field of flux. I plan to use aluminum.

I am plodding along on the last few parts that need to be made rather slowly. My wife is about to retire and she has me busy re configuring her work (hobby) room. I will be posting again in a week or so showing the the distributor system. After that a little pickup work before I try and start it. This is my second IC engine, my first being the Snow Engine. I never got the Snow to run well so I am being meticulous about getting everything just so on this engine. I would cross my fingers but arthritis makes that impossible.

Mark T

 

[gbritnell]

Hi Mark,
The disc should be made from steel. Here's why. When I got involved with Hall trigger ignitions the first disc I made was of brass. When I spun the distributor I got no spark. In my mind I thought that with the brass being non magnetic it should work just fine to block the flux from the magnet, it turns out that it was just the opposite, it needed the steel to absorb the magnetism so that when the timing window opened up it would fire the Hall transistor. I don't know the physics behind it I just know it works. Is there a reason why you wouldn't want to make it from steel?

 

[dnalot]

Is there a reason why you wouldn't want to make it from steel?

No, just over thinking the situation. Steel it is then. Is there a reason for the squared holes? would slots work as well?

Mark

 

[Canyonman]

Dude!!! That's Awesome!! Ken

 

[gbritnell]

Wow! Lovely job on your engine! I can't wait to hear it running. I like what you did with the manifolds.
Mark,
The idea behind the square timing slot was that it would possibly produce a sharper cut-off to the Hall. It might work just fine with round holes but I have never tried it. I have made 6 distributor type engines and have used the square slots in all of them.
gbritnell

 

[ajoeiam]

Hi George
I finished the Holt 75 yesterday.Many thanks for a fine design although I did make a few changes as you will no doubt spot.After I fixed an air leak in the intake manifold it started straight away and ran well , responded well to the governor and had a lovely exaust sound.
Thanks also to Mark for the one way start mechanism.
Attached are some photos and I will attempt to do a video of it running soon .John

Very nice!!!!!!!

 

[gbritnell]

Tol JRR, Mark and any others that purchased the drawings for the Holt. I just made a drawing of the rain cap that I have on my exhaust. It adds a little bling when it's running slow. The drawing is attached.
gbritnell

 

[Steamchick]

A real museum showpiece! Excellent! Well done sir.
K2

 

[teeleevs]

Wow a beautiful job, so pleased when it springs to life.

 

[dnalot]

It has been a little over a year sense I started a build log on the Holt 75. I put a lot of effort into this log and I almost made it to the end before my thread was hijacked. Another member posted photos of his completed engine at the eleventh hour, I feel it would now be anti-climatic to post photos of my engine on this thread. When completed and running I will post photos and a video on a new thread under the “completed projects” category.

Mark T

 

[kuhncw]

Mark, I really hate to see your completed engine separated from your meticulous build thread.
Can the moderators move the other member's posts and comments to a separate thread?

Chuck

 

[gbritnell]

Hi Mark,
Don't take it personal. I don't think there was any malice in his posting he was just enthusiastic about presenting his work. I understand your feelings after all the work and documentation you have done. I for one can't wait to see it completed and running.
On another note, I replaced the rain cap drawing with another. I missed a dimension so I added it to the new drawing.
gbritnell

 

[rpf]

Please carry on, Mark, it is hugely inspirational! even my 10 year old nephew thinks it is a very cool looking engine and is keeping track!!

 

[Robert Ritchie]

Mark I've enjoyed your build from the start, I was shocked when I read a post from a fellow project worker on your same project thread. How does this forum allow such a low level deed by an individual who new exactly what he was doing. I'm requesting an response from the leader of this machinist site, Mark deserves an answer, he has put forth hours of effort towards his engine build only to be out down by by an hijacked thread in which this forum has allowed!

 

[Rdean33422]

I have stopped posting in my thread as well for the very same reason as Mark did.
There seems to be a lot of that sort of thing going on here.

Ray

 

[JRR]

I am astonished at the response I have had to my Holt 75 post. I didn’t realise I would tread on anyone’s toes.I just built it and posted as I have done before.
John

 

[gbritnell]

Hi John,
Everyone has their own personal feelings about things. I have been on model engineering forums for many years and some posters welcome contributions to their threads while others don't. Mark feels very personal about his thread so to rectify the issue I would just take down your posting and start your own thread. I have been following this thread from the onset and would like to see it continue but also would like to see your"s too.
This is a great group which very seldom has any issues, that's why I contribute. Let's keep it civil gentlemen. I'm sure the issue can be resolved amicably.
gbritnell

 

[kuhncw]

I agree with George. This should be easy to resolve. I enjoy both threads and hope they continue.

Chuck

 

[JRR]

Hello George'
I have no idea how to take my posting down. As you can see computing is not a natural with me I really did not realise I had intruded on Mark's site. I thought it was just a general posting. When this is sorted I will begin a new thread.
John