Kerzel hit&miss by Mike

[Naiveambition]

Hey all fellow modelers. Finally picked a new project so this is my choice. I picked this engine for a few reasons. First being its I.C. I looked strongly at the knucklehead by draw tech, Edwards radial five, and Ron colonna' offy four cylinder. And decided these were above my pay grade and when done I want a running model. So felt Kerzel was a good start into ic and its related systems.
Second is I can use this as a ongoing lesson with fusion 360. My thinking here is to stick with one project and work thru it rather than multi projects in the learning forum. And maybe this will clear up some difficulties.

I'm now on my third part. When working on the con rod I ran across a ?. Hoping former Kerzel builders can help me out. In the pic for the crank hole there is a . 376 inside dia. Then .437 dia. What would this represent ? a chamfer maybe,? or is it also showing the bushing. Elsewhere in the drawings is the bushing detail so wandering why it would be included in this drawing.
Sorry guys I tried to post the pic but can't get it done. Keep hitting the pic Icon but nothing happens so let's throw that ? In there and I can post the pic tommorow

 

[kvom]

The dotted line seems to indicate that it's the width of the shaft before the start of the curved portion.

 

[Naiveambition]

After studying the drawing more, I think it would have to be a bushing, bearing. The inside dia matches the dia of crank pin, then a split bronze bushing , with .437 being the con rod dia. I wouldn't think the design calls for a steel to steel engagement which would make sense for the extra feature. Even more so having a chamfer would eliminate the sharp edge of rod for oiling retention and galling.
I've read thru most of Brian Rupnows Kerzel thread and with his I believe he used a alum. Con rod which would enforce the bearing need.
I will also need to check all measurements for fit, Caught one with the crankshaft bearing. Outside dia. of crank bearing journals is..438 and inside dia of bearing is .437. Obviously just reversed when making plans which is understandable considering the amount of work laying out the plans.

 

[jimsshop1]

After studying the drawing more, I think it would have to be a bushing, bearing. The inside dia matches the dia of crank pin, then a split bronze bushing , with .437 being the con rod dia. I wouldn't think the design calls for a steel to steel engagement which would make sense for the extra feature. Even more so having a chamfer would eliminate the sharp edge of rod for oiling retention and galling.
I've read thru most of Brian Rupnows Kerzel thread and with his I believe he used a alum. Con rod which would enforce the bearing need.
I will also need to check all measurements for fit, Caught one with the crankshaft bearing. Outside dia. of crank bearing journals is..438 and inside dia of bearing is .437. Obviously just reversed when making plans which is understandable considering the amount of work laying out the plans.

I have built the Kerzel from Brian's plans and it is a fine running engine. Yes it is a aluminum connecting rod with a split bronze bushing. Have fun building it!

Jim in Pa

 

[Naiveambition]

Ahh some light at the end of my tunnel. Been working away on Kerzel drawings and here is where I'm at. So far I don't have any red flags so am happy about that. I do need to figure out which joints will make the model move correctly. My crank is ok for motion but after that I am lost on the other correct movements.

 

[Naiveambition]

Trying to draw up the head for the Kerzel tonite, and need some modeler wisdom. 2 issues hoping to resolve

In the drawing for the valve cage holes (lines a& b) how do I know the angle distance between the holes --- 360/ by 3?
I see the radius of .219 for the hole layout but not a measurement for the moon shaped one.

And working on valve layout. If my understanding is correct the valve seats are placed in the bottom of head vs the cage itself. I'm guessing the 45' seat is correct? Hoping someone can guide me thru what the "areas in port" section means, cuz this is all new ground for me

 

[kvom]

The three holes look evenly spaced.

 

[Naiveambition]

Ok engine completely modeled in fusion 360. Wow that is a major achievement for me wasn't able to figure joint motion that would work in some cases like cam bobbin an pushrod.
But I am now ready to start machining, but the more look at it , I'm thinking heavily of going double scale. My guess is it should end around the size of 1/3 scale, with 7 inch flywheels. I like the more realistic, or lower revving sound of the larger models. In my hometown the steam thresher reunion would display all sorts of past farm equip. And hit and miss is veery prevalent there. Met a fellow that prided himself on getting the most revolutions before the hit , but when it did it sounded like a shotgun going off. I don't think I ever not jumped when it hit So got used to the sound and is what I'm shooting for plus the added size for constructions sake. (Small tapping not my forte)
Anyways , if I do upsize can I just double the model except for some needlessly thick parts. I'm more concerned with the technical parts like the cam, stroke, piston clearance, etc.

 

[Naiveambition]

Finally around to cutting metal for this build. It is amazing how much more $ wise this motor is vs original size. Looking bout 400$ give or take. Dont know if this is the tariffs talking or what, but every peice seems in the 80$ range.
I stressed over this mounting in every possible way for various reasons faceplate, line boring , milling, etc. and wasn't till I remembered the offset cut in the rear. This gave me just enough holding room to feel safe. Overhang is definitely cumbersome, but with slow feed and rpm is working out so far
Starting out with a 3x5x5 block of 6061. Here Im boring in stages, to keep my tool flex under control till the last few cuts, then will max out the overhang of my boring bar. May make a one time use big bar to finish size. This was the end of nite 1, with low rpm the cuts take forever so multi nights will be on order.

 

[Naiveambition]

After too much trial and error I have made it to this point. I am finding a lot my tools are to small or too big according to what I need for the upscale. This piece has been particularly tricky with mounting. I started in the 4 jaw then managed a taper somehow, then straightened on the mill. I think the correct way would be line bore.
Then turned the undercut for the water jacket. Some chatter marks for pushing the bore cut. Do you change your cutter style when doing undercuts?
Then onto rotary table after making centering disc for locating the bore. I must say me and my rotary table have a very love/hate relationship. Locating ain't so bad but figuring how to mount is mind numbing lol.
Was able to turn down and thread the face to 1/4 20. Hopefully the scale works out. I haven't made the head yet. And topped it off a little over for finishing later.
With this model I am wanting to improve my level of fit and finish by making different parts at different times rather than fit parts as I go. Trying to teach myself not cheat and force better results. This will be by far the most complicated model I've made. Trying to live on the thought " if I just make the parts to spec then all should be good." We will see.

 

[PCT]

After too much trial and error I have made it to this point. I am finding a lot my tools are to small or too big according to what I need for the upscale. This piece has been particularly tricky with mounting. I started in the 4 jaw then managed a taper somehow, then straightened on the mill. I think the correct way would be line bore.
Then turned the undercut for the water jacket. Some chatter marks for pushing the bore cut. Do you change your cutter style when doing undercuts?
Then onto rotary table after making centering disc for locating the bore. I must say me and my rotary table have a very love/hate relationship. Locating ain't so bad but figuring how to mount is mind numbing lol.
Was able to turn down and thread the face to 1/4 20. Hopefully the scale works out. I haven't made the head yet. And topped it off a little over for finishingView attachment 104564 later.View attachment 104563
With this model I am wanting to improve my level of fit and finish by making different parts at different times rather than fit parts as I go. Trying to teach myself not cheat and force better results. This will be by far the most complicated model I've made. Trying to live on the thought " if I just make the parts to spec then all should be good." We will see.

 

[PCT]

It looks like you have a good start. I completed a Kerzel this year, it was a fun project, but I'm still not able to get it to run for anything longer than a few seconds. I'm sure I will solve that problem though. At first run attempt, I had major problems with the mechanical points as shown on the plans. The problem was that the point gap kept changing, I think due to faulty mounting to the block. I eliminated the mechanical points and went with a Hall effect transistor and transistor ignition module from J.E. Howell
http://www.model-engine-plans.com/partskits/ignitionsystems/index.htm With this setup, I got it to pop and run briefly. So, I think ignition is okay, carb adjustment might be wrong, or maybe not enough compression. I haven't given up, I just need to find time to play with it. Good luck with your engine, there are lots of them out there, some of them posted on YouTube, and they run fine.

 

[GreggA]

After too much trial and error I have made it to this point. I am finding a lot my tools are to small or too big according to what I need for the upscale. This piece has been particularly tricky with mounting. I started in the 4 jaw then managed a taper somehow, then straightened on the mill. I think the correct way would be line bore.
Then turned the undercut for the water jacket. Some chatter marks for pushing the bore cut. Do you change your cutter style when doing undercuts?
Then onto rotary table after making centering disc for locating the bore. I must say me and my rotary table have a very love/hate relationship. Locating ain't so bad but figuring how to mount is mind numbing lol.
Was able to turn down and thread the face to 1/4 20. Hopefully the scale works out. I haven't made the head yet. And topped it off a little over for finishingView attachment 104564 later.View attachment 104563
With this model I am wanting to improve my level of fit and finish by making different parts at different times rather than fit parts as I go. Trying to teach myself not cheat and force better results. This will be by far the most complicated model I've made. Trying to live on the thought " if I just make the parts to spec then all should be good." We will see.

After too much trial and error I have made it to this point. I am finding a lot my tools are to small or too big according to what I need for the upscale. This piece has been particularly tricky with mounting. I started in the 4 jaw then managed a taper somehow, then straightened on the mill. I think the correct way would be line bore.
Then turned the undercut for the water jacket. Some chatter marks for pushing the bore cut. Do you change your cutter style when doing undercuts?
Then onto rotary table after making centering disc for locating the bore. I must say me and my rotary table have a very love/hate relationship. Locating ain't so bad but figuring how to mount is mind numbing lol.
Was able to turn down and thread the face to 1/4 20. Hopefully the scale works out. I haven't made the head yet. And topped it off a little over for finishingView attachment 104564 later.View attachment 104563
With this model I am wanting to improve my level of fit and finish by making different parts at different times rather than fit parts as I go. Trying to teach myself not cheat and force better results. This will be by far the most complicated model I've made. Trying to live on the thought " if I just make the parts to spec then all should be good." We will see.

I had the same thought about making parts to print and all went well. The only part I had to fudge was the regulator arm...That part I found, to be a little fidgity but I was able to make it close to the print and then adjust a little here and there. It came out pretty well in the end.

 

[Naiveambition]

Figured I would update where I'm at. Was able to finish up the block machining except for bottom holes. i want to make a base out of welded steel to resemble economy hit and miss engines, plus 50$ just for the base in alum.

Here's a veiw of the undercut and bore. There's some chatter marks on my undercuts but should be ok. This was a hard part to turn in the lathe with the the off balance, I couldn't get anywhere near the speed needed.
The bore went okish with cutter issues but using carbide in my homemade bar was as good as I can for now. I have a 1.5 lap and flex hone on the way . The white marks you see are from my fingernail so that gives an idea of the roughness
.
The rear view and the cylinder ready my first ever shrink fit. I've read another build log and followed his example for a .003 interference fit. So we'll find out how good I did or not
.
Top view with water tank. I chose square to avoid the undercut . I will make a bolt on top later on.

 

[Naiveambition]

Todays work. Started out cutting my pieces from 1/4 angle iron. Welded up the bottom side This pic is before I fully welded, and I'm ashamed to show that photo,! Need to work on my welding
.
Bottom finishing. There will be another base ring around the bottom for aesthetics .

Fly cutting the top after milling for flat surface. I'm happy with my fly cutter , after all my cutter issues , this one cuts great and leaves a nice finish
.
And the part mostly finished. Need to weld two more peices to cover front and above the radius. This radius was made with a 1 1/2 inch pipe and cut a 90*angle out , welded and cut with a hacksaw . With the sides being angled 8* finding a way to hold the work is a little interesting.
And the shot that I will be staring at tonite, till I figure where to start next. I'm sure I'm like most others that stare or play with their work possibly overexcessivly.

 

[jimsshop1]

Nice job so far! I have built the Kersel model myself and also have a full size 2Hp Economy which I completely restored before I built the Kerzel. This restoration was a great help in understanding just how a hit -miss engine works. It usually starts with 2 or 3 turns of the flywheels. The design and construction of both are very similar. Building on a larger scale should make building some of the smaller parts a lot less fidgety. I'll be following along as I want to build a larger scale engine also.

Jim in Pa

 

[Brian Rupnow]

A very nice size of engine to build is the Odds and Ends hit and miss engine by Philip Duclos. If you want to see a picture of the two models (Odds and ends and Kerzel), look in my Dragsaw thread and there is a 3d cad of the two models side by side.---Brian

 

[jimsshop1]

Stupid search function won't work for me.

 

[Brian Rupnow]

See post #14
https://www.homemodelenginemachinist.com/threads/building-a-model-drag-saw.30432/

 

[jimsshop1]

Hi Brian,

Can you please lead me to Philip's plans for the odds and ends engine?
Search does not work for me. Thank you.

Jim