Briggs & Stratton 6S - A Beginnig

[Deanofid]

Thanks for the assembly pics, Bill. That was a LOT of metal to remove inside the crankcase, and things
are really looking good. I enjoy following this build.

Dean

 

[b.lindsey]

Thanks Ron and Dean. I think all of the "hogging" was done in steps using a 3/8" end mill with a 3/8" shank. As long as the deeper cuts don't exceed the outermost dimensions of the shallower cuts things are fine...the shank may rub a bit but it doesn't hurt anything. They do make long reach end mills but I didn't feel it necessary to buy one for just that purpose. I am almost getting to the point where I have to look back through the thread myself to remember how something was done, especially some of the earlier perts that i haven't touched in a while.

Bill

 

[NickG]

Bill,

Keep doing those "see how it's gonna look" shots, I do that too but there's certainly no worry with yours how it's gonna look! :bow:

Nick

 

[b.lindsey]

Thanks Nick...I will try to keep doing that. Its been raining here all day so it was a good day to stay out in the shop working on finishing up the governor. Photo 1 shows the 3 main pieces after the addition of the 1/8"OD x 1/16" ID tubes to both the bracket and vane. Photo 2 shows the lever arm...1/16" brass threaded 0-80 long enought to pass through the vane tube (photo3). For now the vane will be captured by 2 0-80 nuts, one on either side of the vane (see following post).

 

[b.lindsey]

These last two photos show the governor mechanism attached to the plate and in the two extreme positions of its travel. A couple of issues...one is the narrow pivot tube on the bracket. I am worried about its strength so may go back and add a small piece of brass to act as a gusset. The other is the ability of the two 0-80 hex nuts to hold the vane securely enough to keep it from rotating on the lever arm. Maybe some washers and/or semi-permanent loctite will keep that from happening, if it becomes an issue at all. The worst case would be to just silver solder the vane to the lever arm once its final position relative to the lever arm is determined from the throttle linkage, etc.

One problem is that the vane is a little wide and wants to interfere with the inside face of the shroud but that can be fixed by sanding a little off the width, just enough to provide the needed clearance.

 

[arnoldb]

More great stuff Bill :bow: - You're now really getting to the nitty gritty parts!

;D I always love to check in on your thread!

Kind regards, Arnold

 

[b.lindsey]

Thanks Arnold. I can see the finish line at least. There are still a few challenges ahead but for now finishing this crankcase is the biggest and last major hurdle.

Bill

 

[BillC]

Fantastic project! For some reason I thought an NC mill would be needed for this sort of project but you prove that theory wrong!! This is great work and a very enjoyable building sequence....!!!!

BillC

 

[b.lindsey]

Thanks Bill.

Obviously CNC would be a nice trick on the crankcase and head both, but alas...I only work in the manual mode :big: Even better would be a casting set for this engine, but there is a certain appeal to seeing how much like the original I can make it without the advantages of either castings or CNC. If you really want to be amazed with what can be done manually, check out George's thread (gbritnell) on his transmission and the work he did carving out the housing!!

Bill

 

[b.lindsey]

Got a couple of the minor issues fixed today. First the back wall of the crankcase was machined to its final nominal thickness to see if it was enough to keep the con rod from hitting against is and thankfully it was but by a very narrow margin...probaly on the order of .010-.015" but it should be enougn (shown in photo 1). Second the width of the governor vane was reduced to provide clearance with the inner wall of the shroud. Fortunately this worked out well too and its free as a bird now as shown in photos 2 and 3 and if I can get it to work the very short vid clip.

Edit: the clip file may not open by itself but is playable with Windows Media Player.

View attachment Governor.wmv

 

[b.lindsey]

Didn't have a whole lot of time today but did manage to drill and tap the mounting areas for both the carb/gas tank/air filter assembly, and the muffler. This is the first time I have been able to actually hang the off of the crankcase. A few more trial assembly pics follow. Hopefully more progress tomorrow.

 

[NickG]

Wow, absolutely incredible! :bow:

 

[gbritnell]

With all the pieces together like that it must be driving you nuts to get it finished. I know I can't wait to see the first pop from this engine.
Boy that thing sure looks great.
George

 

[Deanofid]

Seeing the new assembly pics is pretty exciting, Bill. I know you have things to do yet, but it's really something to look at!

 

[b.lindsey]

Thanks Nick, George, and Dean. I wish I had progress to report today but things at work were too budy....students working during Spring break...imagine that!!

Also had a lathe breakdown and had to track down and order the part to fix that problem. I did comandeer as mill for the day but had to actually do some other work on it...drats. Well there is always tomorrow

Dean, there is a good bit to do yet but yes, I am getting excited myself too.

Bill

 

[b.lindsey]

The only thing I got done today was to drill and ream the cross hole for the axel pin for the camshaft. The location of that is critical so I wanted to get it done before losing any of the reference edges needed to locate it. This is shown in photo 1.

This evening on the Sherline I worked on making a pulley for the opposite end of the crankshaft. The procedure worked well but I think I erred in scaling it down from a "C" cross section v-belt when I should have use probably an "A" cross section. I will see how it looks with the crankcase but I think it will be a little large and out of proportion. Worst case if I remake it is I will have a useable spare. The little compounf came in handy for this. Some of the steps are also shown below.

 

[b.lindsey]

I will still broach the keyway tomorrow and then decide how it looks, but for now i'm leaning toward remaking it scaled for the smaller section v-belt.

 

[swilliams]

Having not looked in for a while, I must say how impressive the whole thing is looking. Really nice Bill

Steve

 

[b.lindsey]

Thanks for having a look Steve. I won't get anything done today due to other committments, but I have decided to remake the pulley and should knock that out tomorrow...then back to the crankcase on Monday.

Bill

 

[b.lindsey]

Just a quick update on the pulleys. Both are finished and useable but looking at them both on the crankshaft in relation to the crankcase, I still think the smaller scaled down "A" cross section v-belt version looks more proportional. The hub sizes are the same but the OD's and widths of the "v" parts differ. The larger on is 1.25" OD while the smaller one is 1.00" OD. Both are shown in the photos below.

Bill