# (video) my design 4 cylinder OHV engine



## gbritnell (Sep 10, 2008)

Gentlemen, I finally got around to running my 4 cylinder so I set up the camera and took a short video clip. I didn't put it in my original thread because I figured most everyone had been there and might not go again. 
gbritnell
[ame]http://www.youtube.com/watch?v=yYKUlcy-g1w[/ame]


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## kustomkb (Sep 10, 2008)

What a beauty! love the size and sound. Great job, Thanks for the video.


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## ksouers (Sep 10, 2008)

Now that is freakin cool!!  :bow:


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## Bernd (Sep 10, 2008)

Very nice gbritnell. Nice sounding too. 

Question for you. How long could that engine run at say 75% throttle. I'd like to build something like that someday and install it in a swamp boat or airboat. 

Regards,
Bernd


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## gbritnell (Sep 10, 2008)

Thank you gentlemen for the comments. Bernd, If I was going to use something like this for an airboat I would change the cylinder design to aircooled. Why go to all the trouble of a radiator and plumbing when using the airflow would simplify everything. As far as how long it would run at 75% throttle, the only answer I could give would be until parts start to wear out. I have about 3 hours running time on this engine. That doesn't sound like much but when you start it and run it for 4 or 5, 1 minute spurts at model engine shows it takes quite awhile to get 3 hours out of it. I have torn it down once in that time to check wear and the only thing that needed adjustment were the big ends of the connecting rods. I made them out of bronze so I just remove the caps and take a small amount off of them till I get my clearance back, reassemble and fire it up. 
gbritnell


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## Bernd (Sep 10, 2008)

Well yes, an air cooled engine would make more sense, but I like the thought of having a liquid cooled engine. You wouldn't need a radiator since you could use the water the boat sits in. You would just need a pump. 

My main concern was how hot an engine like that would get if run for 20 to 30 minutes continuously at 3/4 throttle or even full throttle. Although I don't think one would do that since your going to throttle up and down as you drive around.

Thanks. It was just some random thoughts I had and since you have built one I thought I'd ask for some first hand experience.

Regards,
Bernd


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## Bogstandard (Sep 10, 2008)

Bernd,

In the early days of radio control model boats, multi and single cylinder four stroke petrol engines were the most used type (glo-plugs didn't come along until later).

Almost any of the old plans for that type of engine would produce a reliable and long lasting power plant. Getting the castings nowadays is the problem, but nothing is insurmountable, and remember, they were made with machinery and materials that to us would be classed as rather basic.

John


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## lathe nut (Sep 10, 2008)

That's not a motor that is a work of art and something that a lot of people would only build in there dreams, I am so impressed with that, that would a life dream to build one like that, you are to good, thanks for the show of you fine work, Lathe Nut


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## rake60 (Sep 12, 2008)

Gorgeous! :bow:

Rick


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## gbritnell (Sep 12, 2008)

Thanks once again everyone. I got started in model engine making many years ago. It started with some Stuart 10v's, water pumps and assorted other miniatures. After a number of years of steam engines I got into gas, mainly some of Paul Breisch's hit and miss engines. Around that time the first NAMES show was taking place in Ann Arbor, Michigan. I didn't get to the first one but made it to the second one and this introduced me to what others were doing with "scratch" building. I designed this engine as a simple inline overhead valve engine. As with any engine, scratch or from castings, there's the machining but more than that is all the tinkering and modifying to get the darn thing to perform well and this one has had it's share of both. At one time as the rings were seating in and the compression came up I had to make a head spacer to get the compression down a bit and now I find that I might have to do it again. The reason I say that is because I would like it to idle a little bit slower but with the high compression, and small flywheel, what you see in the video is about as slow as it will go. It is mean sounding though!
gbritnell


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## DICKEYBIRD (Sep 12, 2008)

VERY nice! Sounds like a little Offy. Luv' that "cammy" idle. Brings back memories of my old 1275 cc Spridget with aluminum flywheel, 11:1 pistons and Huffaker cam. ;D

That little beauty would be awesome in an r/c scale model 60's era midget.

Have you run it in the dark to look at the exhaust colors?


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## Brass_Machine (Sep 13, 2008)

:bow: :bow: :bow:

Wow! I love the sound of that little engine. Very very nice. Job well done sir!

Eric


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## the engineer (Sep 18, 2008)

many thanks for that video it takes a lot of work to get them to run like that you should be very proud of that little gem


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## wareagle (Sep 19, 2008)

That is an awesome looking and running little four banger! Great sound, too! 

*the engineer*, Welcome to the forum. Glad you joined!


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## carbide_burner (Sep 19, 2008)

:bow: (speechless) :bow:


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## Metal Mickey (Sep 20, 2008)

Well I think thats brilliant not only on the quality of engineering but also for your design. Something you must be very proud off. Whats next? :bow:


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## Florian (Sep 20, 2008)

Hey Gbritnell

Really nice engine!
Do you also have some pictures of the individual components? 

Florian


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## itowbig (Sep 20, 2008)

ksouers  said:
			
		

> Now that is freakin cool!! :bow:



i second that. way cool :bow:


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## MadKad (Oct 1, 2008)

wow you made that, every little part even the carb?

is it even water cooled?


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## gbritnell (Oct 1, 2008)

I designed and made all the parts for this engine. It is water cooled, at least the block is. The block is aluminum with the jacket area machined out and then a head plate is pressed onto the iron liners. It has a small water pump on the front to circulate the water. 
gbritnell


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## MadKad (Oct 2, 2008)

WOW that is nice, I would love to make something like this my self.

it looks really good, how long did it take to make?


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## gbritnell (Oct 2, 2008)

Hi Karl, I can't really say how long it took. Some of the time was spent on designing and along the way a little bit of redesign. At the time I built it I didn't know as much about miniature multi-cylinder engine building as I do now so if I were to built the same engine again the time would definitely be far less. If I had to take a guess I would say at least around 350-400 hours. 
gbritnell


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## MadKad (Oct 2, 2008)

Thanks gbritnell

I am really interested in building something like this my self, the only thing that gets me thinking is how to work out how long the valves stay open etc. Would you have any tips?

thanks for your time on these questions also,

Karl.


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## JonnyD (Oct 16, 2008)

Absolutely gorgeous piece of engineering and execution.
I love the sound that it makes.


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## gbritnell (Oct 16, 2008)

Hi Karl, valve timing is generally figured on how the engine is to perform. By this I mean, a high reving engine will have different timing and opening specs than an engine that's going to produce power and torque at lower rpm's. In general the intake will open at 10 BTC and close at 10 ABC and the exhaust will open at 10 BBC and close at 10 ATC. These are relatively mild timing events. 
gbritnell


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