Briggs & Stratton 6S - A Beginnig

[b.lindsey]

Does anyone know of a good source for small oil seals in quantities of under 10 pieces? Will be needing to seal against a shaft size of 7/16" and an OD in the neighborhood of 5/8". Or would a simple o-ring suffice? The 7/16" shaft size seems to be the problem...the usual sources like McMaster have 1/4", 5/16", 3/8" and then jump up to 1/2"

Bill

 

[1Kenny]

Hi Bill,

Try Aircraft Spruce.

http://www.aircraftspruce.com/search/search.php?query=an6227&searchsubmit=Search&search=1

The part number is AN6227B-9 o-ring 7/16 id and 5/8 od.

Kenny

 

[b.lindsey]

Thanks Kenny. Given that it is just a splash lubrication system, an o-ring may be all thats needed. I had been looking for a lip type seal and found them in 1/4", 5/16", 3/8" and 1/2" but no 7/16"

Bill

 

[rklopp]

An O-ring will not survive long as a high-speed rotating seal unless the squeeze is nil. Otherwise, there's too much frictional heat. I was surprised to find that my Aciera mill uses an O-ring as the seal for the spindle nose. However, there is no radial squeeze on the O-ring, and the spindle is grease lubricated, so the seal has an easy time keeping lube in. Mostly it's to keep dirt out.

 

[kustomkb]

Just got caught up.


Super nice work Bill !!

 

[GailInNM]

NAPA has some 7/16 seals, but most of them are about 7/8 OD.

<http://catalog2.genpt.com/catviewer...29786&Nao=30&Ne=1000000&Ns=P_LongDescription>

They have one that has a shaft size of 0.433 with a smaller OD near 5/8 if you have any flexability in that range.

That being said, I have a simple o-ring seal on an air feed on an CNC lathe that has about 1500 hours on it and it is just starting to leak a little bit now. Minimum compression on the o-ring and 80 psi of lubricated air that it is sealing. It is 5/8 ID but I don't remember how much compression I used. It ran a little bit warm for the first hour or so of operation then settled down. I have never pulled it apart to check it. Nominal RPM that I run at is 3200.

Gail in NM

 

[b.lindsey]

Thanks rklopp,Kustom, and Gail. There is some design flexibility in this area but I am leaning to the o-ring idea at the moment with minimal pressure on the shaft. There will be a drain hole between the outer end of the bushing and the seal so any oil that comes through the bushing should drain back into the crankcase. There also appears to be a vent from the crankcase to the inside of the valve pushrod enclosure to minimize any pressure buildup inside the crankcase (see photo). I have also noted on the cover for this area that there is a small slit venting this chamber to the outside. Hmmmm...the plot thickens as they say.

Bill

 

[Deanofid]

Bill, I looked around for seals but didn't find them in 7/16 x 5/8". If you can fudge a little,
this place has metric in 12 x 16 mm, (about .472" x .630"). You'd have to make your crankshaft dia a little larger, but the OD is very close. Don't know how many you have to buy from them:
http://www.epm.com/pg23.htm

If that metric size will do, SKF also shows them, and NAPA sells SKF seals. You could buy just one!

SKF also makes 7/16 x 11/16". Just a 1/16" larger on the OD than you are asking about. Can you make the seal bore that much larger? They are a stock SKF p.n. Oh, 1/8" thick.
Check out this page. Punch in .438 for the ID and it will give you all the standard p.n.'s for that size shaft.
http://www2.chicago-rawhide.com/popup_parts_lookup_457010.htm

Dean

 

[Jared]

Beautiful work!

Check this page out out. http://www.applied.com/apps/commerce/catalog/catalog.do?e=2&c=3256

I found one that was pretty darn close. .624" OD, .437" ID x .125" wide.

 

[rake60]

That is the crankcase breather in your photo Bill.
It is just a very simple little check valve.

Rick

 

[b.lindsey]

Thanks for the resources Jared amd Dean. Between the two sites I think I can find something that will work.

Rick, thanks for the clarification also.

Bill

 

[b.lindsey]

A wee bit of progress on the plate. The larger circle in the center bottom remains to be bored out depending on what i decide on or can find in the way of bushings/bearings/seals. The studs for mounting the breaker/condenser cover (from previous post) and the studs for mounting the coil will be added separately. Even though the coil will not be used I am planning on making a fake one for appearance pusposes only. Thanks for checking in.

 

[arnoldb]

You are cracking along very well on this engine now Bill - great work! :bow:

Regards, Arnold

 

[b.lindsey]

Thanks Arnold....seems like a snail's pace to me, especially compared to some here, but doing what I can, when i can.

Bill

 

[Deanofid]

Wow, you had a lot of milling passes to make on that part, Bill.
You might not think it's going very fast, but every piece you do has a lot
of work in it!

Dean

 

[b.lindsey]

You are right Dean. I wish they didn't show as much but I can liive with it since it will all be hidden anyway. I was anxious to get home and try fitting things together just to make sure there weren't any major screwups. So far so good. Of course I'm still using the RP produced cover for now Here's a few pics of the fitting session. More tomorrow and over the weekend after I do something with that pesky green stuff growing in the yard. :big: Thanks to all who are following along.

Bill

Edit: Not sure why the first pic looks so squatty ??

 

[Deanofid]

Bill, I didn't mean anything bad about the milling lines. I just mean that they showed you had to do a
great deal of cutting to get the piece into shape.

Maybe the 'squatty' shot is just some slight angle of the camera when the pic was made.
Lets just hope that doesn't stick as some kind of nick name!

Dean

 

[b.lindsey]

I knew you didn't mean it in a bad way Dean. Once again the bead blaster kind of evened things out but its hard to fool the camera !! There is some additional work to be done yet on the plate, but i hope to start today on getting the main housing block squared up and flycut to its overall required dimensions.

Bill

 

[b.lindsey]

On the back of the plate there is a thingy that holds the flywheel side bushing and aligns it with the opening in the crankcase. It has two tapered reinforcing ribs and a third one that is not tapered so as to catch the internal oil splash and direct it down through a hole to the ID of the bushing to lubricate it. Other than some basic turning to bring the brass down to size, it was mostly a matter of lots of rotary table work. The bore was left about .010" indersized to be fit to the bushing when it arrives. The oil hole will also wait until the bushing is installed. The bushing will extend slightly beyond the base of this part and insert into the bolster on the plate itself (see previous posts) to maintain alighnemt and this part will be attached to the plate via fasteners. This will no doubt be clearer when the parts can be assembled. Anyway here are a few pictures of this small but critical part.

 

[b.lindsey]

The final two pictures show the tapered ribs and the non-tapered rib which will catch and divert the oil splash. I still have to part it off from thr stock piece of brass. Thanks for checking in !