Model Engine Maker

Engines => From Plans => Topic started by: flopearedmule on July 02, 2018, 10:51:58 PM

Title: Over Crank Engine
Post by: flopearedmule on July 02, 2018, 10:51:58 PM

Hey guys
My dad is building this engine drawn by Julius.   He's trying to get it running, but it won't.
Has anyone else built this engine?  If so, did you run into problems with the D-Vave and the cam throw??
On my picture, I pencil in what the numbers are on the parts, and i put in red what i think they should be.
Can someone check my numbers please?  As it is right now the holes in the port block from end to end is 40mm.  The Valve overall is 36mm
Seems to me the Valve should be at least 40mm or the steam would be trying to push on both sides of the piston.  Also, I think maybe the throw in the cam should be 16.5mm (offset in the cam should be half of that...8.25)???
What do you guys think?? I was going to post in the part with the Prints, but i got a big warning to make sure I want to do that.  Thanks

Title: Re: Over Crank Engine
Post by: sbwhart on July 03, 2018, 06:58:12 AM

Hi

Jules based his drawing on my design, I had no problems getting my engine to run if you PM me with your email address I'll send you my drawings.

This is my engine running

https://www.youtube.com/watch?v=FBEsz7imfh8

Stew

Title: Re: Over Crank Engine
Post by: Jasonb on July 03, 2018, 07:29:38 AM

Julius has drawn the slot for the nut the wrong way round   :facepalm: the longer 39mm dimension should be compared to the 40mm of the ports.

Also the valve on Julius drawing is still 1mm short, Stew's drawing has the block larger than the slots by  1.1mm and given that his original was half the size of Julius version you should have a valve of about 43.2mm

Title: Re: Over Crank Engine
Post by: flopearedmule on July 03, 2018, 01:41:43 PM

Thanks guys,
I think the throw of the cam should be 16.5 also.  I guess it would probably work if it was a bit more.
I was comparing the numbers on the over crank prints to the engine I built this last winter (conventry)
The throw of the cam (on the Coventry) matches the center of the ports exactly. The valve is a bit longer than the total across the ports.  1mm is what I will go with.
I will let Dad know and he can get this beast running.  He also scaled it down to half size. 

Title: Re: Over Crank Engine
Post by: Jasonb on July 03, 2018, 04:17:07 PM

Stew's would double up to 17.2 throw as it was 8.6 or 4.3 offset on his original.