Holt 75 Model Engine

This is a fully working model of a 4 cylinder Holt 75 petrol engine. These were used around 1915, mainly in the USA, to power tracked military and earth moving vehicles. The original had a capacity of 22.9 litres and produced 75 horsepower at 550 rpm.
The model has a 1” bore x 1 ¼” stroke to give a capacity of 64cc. It will idle about 700rpm and go up to 4000rpm, but being a fairly long stroke it better suited to lower speeds.
It was built to a design by George Britnell and was constructed entirely from stock materials using manually controlled machines over a 9 month period.
It runs on petrol and has a distributor for spark ignition. Lubrication is by splash and it is cooled using a pump and a computer radiator.

[@skysurferuk]

You've every reason to be proud, sir! A wonderful creation. 👍

[@MrBoehol]

I love the sound.Just like a full scale Holt engine. Very nice work. Thanks for sharing.

[@ManualdoMotorStirling]

Congratulations on your engine perfection!
I found it very well manufactured, I can imagine the difficulties for a good operation.

[@michaelstratton6059]

Thanks. The distributor was a problem as the voltage needed to produce a spark does not scale well!

[@rogueart7706]

I’m jealous. That is really cool.

[@alireza.beyranvand]

VERY NICE WORK ...U IS GREAT

[@igorsilvademorais7967]

Very good,

[@mechrizz1235]

Nyz work bro

[@darrenfawcett9912]

Well done Michael, runs nice and slow

[@michaelstratton6059]

Thanks, having two flywheels helps

[@DragonPlauge2806]

Very nice engine bet it took ages to make wish I had the skill to make one

[@WhatDadIsUpTo]

Wow! You did good. What's the displacement in "?

[@michaelstratton6059]

The displacement is 64 cubic centimeters (cc) or 3.9 cu in

[@shelbylangston1270]

Do y0ou wish to sell this model?

[@michaelstratton6059]

No thanks, it took too long to make.