Holt tractor engine

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gbritnell

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Gentlemen,
It seems like there is some interest in building the Holt tractor engine. The question has come up about Coles demise and the subsequent loss of castings and drawings. Discussion has come up about copyright infringement on selling copies of the drawings and to the point of selling one's legally purchased prints.
When I took an interest in the Holt engine quite a few years back from seeing several versions at old engine shows I spoke to the builders about the engine and found out what they liked and didn't. The biggest issue was the way the crankcase had to be machined for the main bearings. It required some reasonably accurate filing, mounting the main bearings then line boring them. This meant that the main bearings once mounted had no real way of relocating should they need to be removed or replaced. Other issues were with the quality of some of the castings.
With this in mind I purchased a set of drawing from Coles (the original business in California) along with the large flywheel, intake and exhaust manifolds. I then started making drawings to build my Holt from bar stock.
Since completing and running my engine for many years I have discovered things that I would have designed differently from the original drawings. With these thoughts in mind and seemingly some interest in the engine I have started making drawings based on my scratch built version.
The engine will have a split crankcase making it easier to machine. It will have O-ring seals on both ends of the crankshaft. The ignition will be triggered by a Hall transistor setup. The plumbing will be a little larger to provide better cooling.
All the parts will have some detail to them (bosses and shapes) but will be able to be made without the extra work to create a running engine. The majority of the parts will be made from aluminum with 1144 steel for the cranshaft, W-1 drill rod for the camshaft, and 932 bronze for bearings.
The drawings will be done in Autocad in 8-1/2 x 11 format. (Approximately A4 size) and will include drawings for a water pump, radiator, plumbing, fan and brackets.
I have the crankcase drawings complete and hope to have the remaining drawings finished by at least late summer. (August-September)
So for those of you who would like to build a Holt, hang in there for awhile.
gbritnell
 

aka9950202

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I would like to built on of those engines someday soon. The question i have is can it be made using a Seig 7x10 lathe? I do have a small mill as well.

Could i produce my own casings insread of hogging out bar stock.

Cheers ,
Andrew in Melbourne
 

gbritnell

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HI Andrew,
The crankshaft would be a little over the capacity of a 7 x 10 but I certainly can't judge what some people are capable of.
gbritnell
 

dnalot

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I will be ordering a set for sure. I am reserving next Winter for the project.

Mark T
 

CFLBob

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This could be a big revision to my plans for the next year!

Sign me up for updates so that I know when they're available.


Bob
 

kadora

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Hello gbritnell
Could you please send detail picture of Holt engine water pump?
Thank you
 

CFLBob

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George, I meant to ask you a question.

One of the reasons I got the idea to build the Holt 75 was from seeing one at Cabin Fever back in 2015. In fact, I took a video and a photo, which doesn't show it very well.

I can track down that your POTM for the engine was before this. My question is if this is yours?


Inline-4.jpg


That would be a remarkable "it's a small world story".


Bob
 

gbritnell

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Yes, that's my engine.
gbritnell
 

gbritnell

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As an update to this thread I have finished the drawings for my engine. I say my engine because of the many changes and modifications that have been done to the original. Bad weather in this part of the country, and other things, allowed me more time at the computer.
Please contact me at: gbritnell@yahoo.com for further information.
Thank you,
gbritnell
 

dnalot

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Hi

I purchased a set of drawings from George a week ago. They are nicely done and I am looking forward to getting started on the project this fall. I think there are going to be a lot of little Holt's before long.

Mark
 

dnalot

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Hi

I have my fingers crossed that Aonemarine will be casting intake and exhaust manifolds.

Mark
 

aonemarine

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Hi

I have my fingers crossed that Aonemarine will be casting intake and exhaust manifolds.

Mark
Something told me that those would be the most wanted castings, and likely the hardest ones to cast. Ill have to grab a set of drawings from George just to verify the measurements to the originals before getting started.
I probably wont be able to get started on them until September due to my current work load though.....
 

JRR

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G’ Day George
I am also interested in purchasing a set of drawings for the Holt. Please add my name to the “gunner buy” list.
Regards
John
Bannockburn Vic Australia
 
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