Briggs & Stratton 6S - A Beginnig

[BillC]

Oh yes, the fins. That is going to look cool.... :bow:

BillC

 

[b.lindsey]

It should look something like this from the back side

View attachment BS6S Crankcase3 (1).pdf

 

[kustomkb]

Awesome work Bill! It's coming together beautifully.

 

[b.lindsey]

Things are still crazy busy at work with the end of the semester only two weeks away so progress for me has been slow, but I did manage to knock out the little valve cavity cover which will fit onto the back of the crankcase. Its an odd shaped piece and the original was obviously stamped whereas mine had to be fabricated. Its not especially critical and some of the contours and bends may have to be adjusted slightly at assembly but all in all its a reasonable facsimile of the original I think. This was try number two by the way as I wasn't at all happy with the first attempt. The pictures should be pretty self explanatory I think. After milling out the basic shape from 1/8" aluminum sheet the angled surfaces were milled with the help of the Sherline angle plate and vise as shown in photo 1. Photo 2 shows the mounting hole (center) and the smaller hole (left) for any crankcase pressure to escape to the outside via the breather which will be inside the valve cavity. There is a small bent tab along the top edge so a dremel cut off wheel was used to slit that area (photo3) and the vise used to bend the tab back (photo 4).

 

[b.lindsey]

The small exit hood which again was stamped on the original part as can be seen in the last photo had to be fabricated from a small round of aluminum, bored out and then cut at the same angle as the face of the cover (photo 1). This took some sanding/filing to bring it down to a proper sized "fingernail" as shown in photo 2 sitting atop an M&M. Finally I attached it to the cover with some JB weld and will leave it to sit overnight to cure. Then I will bead blast the whole thing again. The last photo shows the model part next to the full size stamping. If not exact, it is close enough I think both from a cosmetic and functional standpoint.

 

[Deanofid]

Looks pretty darn close to me, Bill. When you round the corners an little and with the bead blasting,
it should measure up just fine.
I can see quite a bit of time in that little thing!

Dean

 

[metalmad]

How nice is that
Pete

 

[b.lindsey]

Good point Dean. The corners will be rounded though when I fit it up finally. The raised lip around the valve cavity will need to be rounded also but they will need to be done together to match up. A little careful filing should take care of that detail. Thanks to you and Pete both for checking in.

Bill

 

[b.lindsey]

After curing overnight, the JB Weld seems to have provided a good bond so here are just a few follow up pics of the finished cover (less corner rounding). It does show some of the odd angles and curves though as this is more than just a 2 dimensional cover and for some reason (more likely a mental block on my part), it gave me fits trying to draw it in a front/top/side view format.

 

[joe d]

Bill

I'm running out of superlatives when I look at your work on this.
Very much enjoying following along!

Joe

 

[b.lindsey]

Thanks Joe...I just appreciate your following along. On the other hand, I am sometime at a loss for @$&%* words while doing it, especially when I have a senior moment...lol!!

Bill

 

[arnoldb]

Bill, ;D :bow: Thm:

Kind regards, Arnold

 

[b.lindsey]

A couple of little bits done today as well as some CAD work on the crankcase breather parts. Not a lot but made the stud and nut for the valve cover as shown below. The last picture shows where the cover will fit although until I get more of the top of the crankcase machined it won't fit flush yet. Happy Easter everyone... hope the Easter Bunny finds your shop ;D

 

[b.lindsey]

Things are still going slowly as our seniors are all going full tilt to complete their senior design projects by next Friday for the big EXPO here on campus. After that its exam week and then the Summer so things won't be quite so hectic. In the meantime I have finished the three little pieces needed for the crankcase breather...the spring, body and seal. The body was turned from a small piece of bronze i had (photo 1) and the 3/16" nipple was then cut leaving two fingers which will extend into the hole between the valve chamber and the inside of the crankcase. These appear to be just to keep it aligned over the hole. The three parts are shown in photo 2. The upper end of the spring rests against the lower side of the threaded stud which secures the valve chamber cover on. Photo 3 shows the parts next to the original and photo 4 showns the assembly next to its big sister. I had thought about using gasket material for the seal (the black part in the pictures), but then found a piece of delrin that I used instead. If it ends up getting too hot and sticking or melting, the I can come back and replace it later...maybe by then I can get a little shim stock punch set I have been looking at for a while when it goes on sale next. Thats it for the moment, though I have gotten the 1/8" face width slotting saw needed for making the fins.

 

[BillC]

The M&M adds flavor.... Remember the old days when a set of points had a little capsule with them? I always thought it was pretty nice of those folks to include a pill to calm you nerves while you were replacing your points..... :big: I wonder if anyone really did that?

You're doing some grand stuff here Bill! It's a pretty little engine too. It's ideal too being air cooled with the B&S cooling fan. This is a little jewel.

BillC

 

[b.lindsey]

Thanks Bill. Well in this case, the little orange pill met with a quick demise after i took the pictures, not for nerves, just pure enjoyment :big:

Thanks for checking in.

Bill

 

[Chaffe]

Absolutly amazing, watching every step of this. cant wait to see it run!

 

[b.lindsey]

Thanks Chaffe. Today in a little spare time, I cut out, drilled and bent the Oil Splash Shield that fits just inside the valve cavity under the cover. I am assuming its purpose is to let any excess crankcase pressure out via the small vent in the cover, without letting out any oil that may accumulate in the cavity. Nothing much to show in making it but a couple of pics are included, one next to the full size one and one where it will fit on the crankcase. I had hoped to make it out of some blue tempered spring steel shim stock (.010" thick) but didn't have any handy and wasn't going to pay 8 or 14 dollars for a small piece plus shipping when i only needed a small bit. Opted for some .009" brass shin stock I had on hand.

 

[the engineer]

in the time i have been watching this thread i have been amazed and thrilled to see this little gem evolving many thanks
i have built the three horse version of the later engine(1970 1980) into parallel and 180degree twins
my loving wife un beknowing to me sent a photo to the briggs motorsport depot and later on she presented me with a signed letter from mr fred stratton himself of which i prize dearly
i suggest that you should do the same your work is so impressive i am sure they would respond also
once again many thanks cant wait to see more
regards john

 

[b.lindsey]

Thanks John. I do plan on contacting them once it is up and running if only to make sure there would be no problem in offering the plans for the model since it obviously bears their name and hopefully a striking resemblance to their engine as well. I can well imagine that the letter from Mr. Stratton is certainly one ofo your prized posessions!!! Have you posted pictures of your "twins" previously? Would love to see them.

Regards,
Bill