Briggs & Stratton 6S - A Beginnig

[kustomkb]

That really is a project unto itself. A real fine piece of jewelery you have made. Er, scratch that, jewelry doesn't do anything!

Very nice.

 

[b.lindsey]

Thanks Kevin,
I'm not so sure this sub-assembly will do anything either....yet. I do know it will hold liquid without leaking, but whether the little carb will suck it up out of the tank remains to be seen.

Bill

 

[t.l.a.r. eng]

Outstanding build! I am amazed at the progress and dedication.

Have you considered putting the check valve in the end of the fuel pick-up pipe?
It would have a major affect on the way the engine starts and runs. A small brass foot and tiny stainless ball should work like the original. You could even add the screen like the originals.
I don't remember if the earlier engines used the check valve, but I know the later ones did. It keeps the fuel in close proximity to the main needle valve so the fuel doesn't run [drain back] away from the valve between intake pulses.
Just my .02 and not worth a whole lot more than that.
Gary

 

[b.lindsey]

Gary,
Yes that is something yet to be added to the bottom of the pick-up tube and I agree with you, it should help the performance....now ...any ideas on finding a 1/16" OD SS Ball?? I am not sure when they began adding this but the prototype I am working from does have it. so that would be around 1950-51. Thanks for the observation and suggestion!!

Bill

 

[mklotz]

now ...any ideas on finding a 1/16" OD SS Ball??

Ball-point pen, perhaps?

 

[b.lindsey]

That's a thought Marv. I will try to dig one out, clean it and measure it. I am sure I could buy some from McMaster but only need one so would rather not go that route yet if I don't have too. Thanks!!

Bill

 

[gbritnell]

Hi Bill,
I'm sure I have a .0625 stainless ball in my stash. I'll look and let you know. If I do I'll drop it in the mail for you. Personally I don't think you'll need it. I have never used one on my hit and miss engines and they draw fuel from farther away than yours will.
On another note, having gone through the carburetor maze, I would try a very simple carb that is known to work before using your beautiful replica. The reason being that I have scaled down several carbs from full sized engines and haven't had much luck with them. The physics just doesn't scale down well.
gbritnell

 

[Deanofid]

now ...any ideas on finding a 1/16" OD SS Ball??
Bill

Bill, I have some. They are actually in metric sizes. I have 1.5mm and 1.7mm. So, .059" or .067".
Let me know if you can use either of those and I can send you a couple, or a couple of each.

I keep a few different sizes on hand for various camera repairs. They're used as detent balls.

Dean

 

[b.lindsey]

Thanks for the offer Dean. Taking Marv's advice I took the roller ball out of a ball point pen yesterday (actually 3 of them having lost the first two...geeze they are small) but hung on to one at last. It measures .040" dia and may work...just need to draw up what and how I want to do for the check valve arrangement. If the .040" ball doesn't work I may take you up on your gracious offer. Thanks!!!

Bill

 

[swilliams]

Hi Bill

I've been reading your detailed description on making the rings way back on page 16
http://www.homemodelenginemachinist.com/index.php?topic=6014.225

I think it's really good and plan on doing similar for my engine soon. BTW I'm really impressed with your great build and what you are able to do with your little machines.

Cheers
Steve

 

[b.lindsey]

Thanks Steve, I was certainly pleased with the results as a total newbie making rings. No more than most of these engines run, the lack of heat treating shouldn't be a problem and as I noted back in that post, the fellow that told me about the method now swears by it and has MUCH more experience than I do. I would still make some extras...just in case. Even though I was amazed at their ability to stretch over the OD of the piston, cast iron is still a brittle material.

Bill

 

[swilliams]

Thanks Bill

The tip about making some extra rings is a good one. I think I would have over looked that one if you hadn't brought it up

Steve

 

[b.lindsey]

Minor update...Have started back to work on the crankcase...nothing major but gettiing it gradually down to size. Hope to be able to get some work done over the weekend. In the first two photos, the width was reduced on the oil filler end, just some straightforward milling.

 

[b.lindsey]

The next 3 photos show facing off the flywheel side of the crankcase by .031" leaving a small raised circle where the outer plate will attach. Photo 1 shows using the coax indicator to canter on the mounting hole. Then the rotary table was used to mill away the material on that face with the exception of the mounting flange, hence the circular tooling marks.

 

[zeeprogrammer]

Just managing to peek in the forum once in a while...

Nice stuff Bill. So you went with the blue M&M? I see them a lot on this forum. It tells me all you guys like the reds, greens, and yellows. Not surprising...we all like the shinier ones.

I'm always surprised by the smallness and detail of your work. Very nice.

 

[b.lindsey]

Hey Zee, checking in every so often is about all I have managed too of late. Things have been waaaaaayyyyy to busy at work lately. I just need to get back to doing a little something every day and the ptogress will manage itself. Thanks for checking in though.

Bill

 

[Deanofid]

We all get busy, Bill. Sometimes the projects have to wait. Looks like you made a good bit of progress
on this last bit, though. I liked the part shown next to your print. Gives us a good idea of what's what!

Dean

 

[b.lindsey]

All too true Dean! What with teaching the "Machine Shop Practices" course, co-teaching the two lab sections for the same course, and making sure all the other labs are set up properly...the days go by fast. But I love it all and feel so fortunate to be able to say that. Still...a little more fun time would be nice I do hope however, to get some further whittling on the crankcase done this week, starting today. I am getting antsy now to see the shape of the crankcase emerge from that block of aluminum.

Bill

 

[b.lindsey]

Time for a brief update since its been a couple of weeks. Chip making has slowed considerably for the moment as it became apparent that to go any further on the engine block would reguire completing the design and drawings for the internal components, especially the crankshaft gear and the one piece cam gear/shaft/cams. These too had to be scaled down and being a newcomer to making gears I am slower at this though I must say learning a lot in the process. This all had to be done to figure the center distance between the two gears and therefore the location of the cam shaft in the crankcase, which effects the location of the valves, etc. etc. Anyway I did get a start on the cam shaft this weekend as shown in the below photos. As per the original this is being made from cast iron though the crankshaft gear will likely be steel. Complicating this somewhat (for me at least) is the roughly 25 degree angle that the teeth of the gears are cut on. I am assuming this was done for noise reduction in the prototype but whatever the reason I am going to try to use the same angle in the model. I have the cutters in hand and am working out the set-up for doing this on the Sherline mill. As the two gears are 18 & 36 teeth, the rotary table, mounted on an angle plate I am hoping will suffice as long as I can make it rigid enough. Since the cams are timed to the gear teeth on the cam shaft they will be cut after the gear is cut. I think all the angles have been figured correctly per the prototype but only time will tell. The tappets will be made from drill rod and hardened. At times these details get to be mind boggling!! Hopefully I will have more progress to post in the next few days.

View attachment BS6S.pdf

 

[arnoldb]

Bill, your engine's coming along great :bow:

Regards, Arnold