# Atkinson engine



## gg89220 (Feb 20, 2021)

hello
start of construction by the crankcase


----------



## johnmcc69 (Feb 22, 2021)

Looks like you're off to a great start! Nice looking parts!

 John


----------



## gg89220 (Feb 23, 2021)

hello
the regulator, the connecting rods, the crankshaft


----------



## dsage (Feb 24, 2021)

Which plans are you building from?


----------



## gg89220 (Feb 24, 2021)

hello
found on this forum 





__





						ATTKINSON 2021 - Google Drive
					






					drive.google.com


----------



## dsage (Feb 24, 2021)

Should be interesting. It might actually work. I have a friend with one built from these plans that works. It looks like you are well on your way. I'll be watching with anticipation.

Thanks for posting.


----------



## stragenmitsuko (Feb 25, 2021)

will be folowing along


----------



## gg89220 (Feb 27, 2021)

hello
connecting rods, flywheel, axles and bushings


----------



## dsage (Feb 27, 2021)

Moving right along. Nice work. Also a pretty unique flywheel.
Thanks


----------



## gg89220 (Mar 5, 2021)

hello
intake, carburetor, exhaust and tank


----------



## dsage (Mar 5, 2021)

This is getting interesting. Nice work. 
Is that a common bolt you are using as a valve?? I see a philips head on it.


----------



## gg89220 (Mar 11, 2021)

hello
cylinder and pistons to finish 


dsage said:


> I see a philips head on it.


yes


----------



## dsage (Mar 11, 2021)

Very nice.
Have you changed anything from the drawings?
I hope you can make a video. I'm anxious to see it run.
Very cool.
You work fast.
Thanks


----------



## gg89220 (Mar 15, 2021)

hello
painting and final assembly 


dsage said:


> Have you changed anything from the drawings?


no


----------



## dsage (Mar 15, 2021)

AND........ (is a video forthcoming ?)

You did a nice job making it look antique with the color scheme etc.
Nice.
Thanks


----------



## Steamchick (Mar 16, 2021)

An excellent job! - Well done Sir.
How about a few nice little brass oil-pots on the crank main bearings and other strategic locations? I always like to see lots... and especially when someone makes a central feed to the big-end of the crank, so you see a small diameter brass tube from the end of the crank-pin to a collector that is at shaft centre, with a separate oil pot and feed pipe to drip into the collector. Odd little details can personalise a model and entertain us lesser mortals.
But well done!
K2


----------



## bluejets (Mar 16, 2021)

Looks like the flywheel has been cracked on the mounting at the grub screw....bit heavy handed tightening..??
Might have to make a steel ring for there to keep it together.
Photo 3 .....#14

Now the big question, does it run..?


----------



## gg89220 (Mar 17, 2021)

yes it is running, soon the video


----------



## Steamchick (Mar 17, 2021)

gg: Maybe a single drop of Loctite screw-lock will ensure it doesn't move on the shaft anyway?
Personally, I would remove and silver solder the flywheel, IF it needs to be repaired.  Then carefully ream the hole back to size. (The Cast Iron may shrink very slightly with heating, or it may not be significant to affect the sliding clearance onto the shaft? (N.B. Cast iron exhaust manifolds can shrink 1 to 3% in their lifetime - but after many heating cycles... - Maybe the carbon is burnt-out by heating? Can a material scientist explain please? A curious material! - I once bronze brazed the skirt on an engine cylinder with a short (1") crack in it. Afterwards the skirt was thou or 3 smaller than the rest of the bore. - The piston was a good fit in the top 3/4 (above the base flange of the cylinder), but tight for the last 1/2" or so, A judicious application of emery where the engineer's blue indicated made a good fit, but a house moved forced the sale before I got that bike built and running, so I don't know if the repair worked...).
K2


----------



## gg89220 (Mar 18, 2021)

hello
engine video


----------



## Gordon (Mar 18, 2021)

Great work. At least you have proven that it can run.


----------



## propclock (Mar 18, 2021)

Fantastic you are a true owner of a Unicorn as far as I have read, like the guy that routinely actually uses his Quorn to sharpen an end mill. 
Congratulations ! what is all the liquid in the center?  I think as an outside observer
the CDI ignition helps as mentioned by Grim in another Atkinson post and a large flywheel. 
The proof is in the running,  again congratulations.


----------



## dsage (Mar 18, 2021)

Wow. Fantastic. And it runs with such authority too !!
Looks like you have wonderful compression. What process do you follow to make your rings. Many have been discussed on HMEM.
I think I might abandon my Gingery version (that I considerably modified) and start over.
        So, to be clear, you didn't change anything from the original drawings presented on HMEM earlier. I don't want to go down a dead end again.
Thanks much.
 A couple of words would be appreciated.


----------



## dsage (Mar 18, 2021)

propclock said:


> Fantastic you are a true owner of a Unicorn as far as I have read, like the guy that routinely actually uses his Quorn to sharpen an end mill.
> Congratulations ! what is all the liquid in the center?  I think as an outside observer
> the CDI ignition helps as mentioned by Grim in another Atkinson post and a large flywheel.
> The proof is in the running,  again congratulations.


Propcock the water is for cooling. There is a passage from the hopper to surround the cylinder. The Gingery uses this method as well.


----------



## gg89220 (Mar 18, 2021)

I bought the segments, it doesn't have too much compression I threaded the valve stems easier to find the right spring flexibility the ignition point is precise


----------



## stragenmitsuko (Mar 18, 2021)

A fine runner 

Félicitations ! 

You dindn't use the governor as gar as I can see ?


----------



## dsage (Mar 18, 2021)

gg89220 said:


> I bought the segments, it doesn't have too much compression I threaded the valve stems easier to find the right spring flexibility the ignition point is precise


Segments??
I assume you mean the rings? Good idea.
Excellent idea for adjusting the springs.
Thanks


----------



## johnmcc69 (Mar 19, 2021)

Outstanding! Congratulations!
 They DO run!

 John


----------



## coulsea (Mar 20, 2021)

Very nice engine. I need to live to 110 years old because my to do list keeps getting longer.


----------



## dsage (Mar 21, 2021)

johnmcc69 said:


> Outstanding! Congratulations!
> They DO run!
> 
> John


They??
Well. I had little doubt (if made properly) the Pendegrast designed engine would run. It's the Gingery version that has problems.


----------



## Steamchick (Mar 22, 2021)

gg. I think you have made an excellent model of this engine and justly deserve the Model of the Month for this one. A true bit of craftsmanship to make such a sweet running engine, of a relatively difficult design. (Looks easy, but  so many comments about difficulty of making them run suggests you have "the knack").
K2


----------



## dsage (Mar 22, 2021)

gg. Would you be so kind as to check the positions of your pistons when they are fully to the left in the cylinder with respect to the spark plug hole. I have redrawn the drawings and run an animation and this is what I get. The spark plug hole seems to be partially block by the piston. I'm just trying to confirm this is correct. 
Thanks


----------



## gg89220 (Mar 22, 2021)

hello
it passes a Ø 6 mm drill


----------



## dsage (Mar 22, 2021)

Excellent. Thank you very much. I'll consider it normal and continue. That's good. I don't have to go looking for errors in my re-draw.
Thanks Again.


----------



## Aerostar55 (Mar 22, 2021)

dsage said:


> Which plans are you building from?


There’s a book by Vincent Gingery step by step building an Atkinson engine


----------



## dsage (Mar 22, 2021)

Yes. A book to be avoided at all costs. See various other threads on the Atkinson engine.


----------



## Dave Perreault (Mar 23, 2021)

Nice... Glad to see people are still interested in this James Atkinson engine!

This is my Atkinson Differential engine that I designed and built.


----------



## Steamchick (Mar 23, 2021)

Hi Dave, are you selling paper plans? (I.E. Not CAD)?
Ta,
K2


----------



## dsage (Mar 23, 2021)

If you've been following along the plans are already posted back in message #5 and elsewhere in another thread. I'm just re-drawing those plans to be sure I understand them.


----------



## Dave Perreault (Mar 23, 2021)

Steamchick said:


> Hi Dave, are you selling paper plans? (I.E. Not CAD)?
> Ta,
> K2


I have plans and casting kit that I sell....
I have one casting kit left ....


----------



## Steamchick (Mar 23, 2021)

dsage said:


> ... the plans are already posted back in message #5 and elsewhere in another thread. I'm just re-drawing those plans to be sure I understand them.


Got it. I just wasn't sure if these are the same as Dave P's plans? - I had an idea his Mini A had an extra valve - or something different - and had been de-bugged already.
K2


----------



## Steamchick (Mar 23, 2021)

Dave Perreault said:


> I have plans and casting kit that I sell....


Maybe you can let me know how I can order a set of plans for your Mini-A? Do they e-mail for me to print, or do you post from Freemont?
Ta,
K2


----------



## Dave Perreault (Mar 23, 2021)

Just to clarify.....
I have designed and made several Atkinson cycle engines....
The video I posted above is my 10" flywheel casting kit. Aluminum castings and prints.

All my Mini engines at made from bar stock.
Plans only.

If you do a search on youtube for 
"Dave Perreault Atkinson engine casting kits" you can view all that I have made and them running on my YouTube channel
Regards Dave


----------

