A relic from the age of iron.

[65ShelbyClone]

Just thought I'd share one of my unusual engines. It's a B&S model 14 built I suspect some time in the '50s. The "14" apparently stands for 14 cubic inches and was a 5hp model. It has a small bore and long stroke and makes tons of torque while doing it smoothly. Nice and docile...of course I had to fix that. :shifty:

Here is a nice restored example of what they look like:

And here is mine:

The magneto is separate from the flywheel, so I made a little aluminum one to replace the 12lb iron stocker. I also took the liberty of milling the head a lot too much, porting the intake side, and back cutting the valves. I found out the hard way with bruised hands that the cam-mounted compression release no longer works.

I have it all torn apart right now so I can do some more porting. This thing has some huge valve guides(5/16" stems) and I need to carve on the part that sticks into the port. It would be cake to fit an oversized titanium intake valve if I was still working in a machine shop.

 

[minidragbike]

Have you measure the stock rod length?
Also how large is the crank journal?

 

[65ShelbyClone]

Yeah, I actually planned on making a billet rod for it, but never got around to doing it.

The rod journal is the standard 1.00". My quick and dirt measurements show a 5.743" center-to-center length. This is just done with calipers and is likely off by up .010" or more.

I was going to make an even longer rod so I could use a really light Tecumseh 4hp mower piston(same bore, but shorter compression height).

EDIT: Oh yeah, a comparison pic between the original flywheel and what is on there now...

 

[minidragbike]

Man that's a long rod in that thing. Making a rod isn't to easy to do, wish you luck.:001_unsure:

 

[RuppParts]

a small block chevy rod length!!!

 

[Yellowhand]

There ya go...fab an insert for the crank journal and use a Chevy rod in it...let's see that one break...

 

[65ShelbyClone]

I'd love to be able to do that, but even the stock rod has a sloped area to clear the cam. I'd also have to bush the pin end for the Briggs's .675 pin. What do Chevies use? It's a .912, right?

I forgot about this other old relic I also have:

It's a Wisconsin of unknown model that came an ancient cement mixer. The whole mixer was damaged in a forest fire that came through here three years ago and it was given to me. All I wanted was the engine. :chinese: It has a chain-drive 6:1 gear reduction and everything but the head is cast iron(read: heavy). I pulled the reducer box off and it appears to have tapered roller bearings on at least the PTO side. It's not worth much and too heavy to be practical with shipping, so I'm not sure what I'll do with it.

 

[minidragbike]

You would never be able to use a Chevy rod. It's just to big on both ends, and way to heavy. And I don't believe ARC makes any rod that long. Your best bet is to go to a junk yard and try to find a small import motor with a long rod setup?

 

[deezildennis]

. It's not worth much and too heavy to be practical with shipping, so I'm not sure what I'll do with it.

I'll take the Tank if its for sale and not dented all to bad.
Pm me if its for sale.

 

[65ShelbyClone]

You would never be able to use a Chevy rod. It's just to big on both ends, and way to heavy. And I don't believe ARC makes any rod that long. Your best bet is to go to a junk yard and try to find a small import motor with a long rod setup?

Yeah, the Chevrolet rod is a 2" crankpin and WAY too wide. Heck, if you put the stock Briggs rod in backward it will hit the cam.

I'll take the Tank if its for sale and not dented all to bad.

It's not dented at all, but I want the tank for the same reason you probably do. :shifty:

 

[Yellowhand]

I guess I should have put LOL or something in the post about using a Chevy rod in that engine...I was just kidding...

But, I've learned to not speak in absolute terms when talking about fabrication and modification...I rarely use words like 'never' and 'impossible', because I hang out with a bunch of old farts with decades of machining and fabrication experience, and a history of turning 4hp engines into 24hp engines and putting them in quarter midget race cars.

These guys have CNC machinery now, so all the weird ideas they used to say were impossible are now just 'financially irresponsible'...they can make just about anything, and make it work remarkably well...it just costs more than they're willing to spend sometimes.

Besides, that engine is just begging to have some new components made for it...look where the spark plug hole is located in the head...

 

[delray]

hey 65ShelbyClone, can you grind and polish the con-rod beam for strengh? also can the rod be treated with something for strengh? I know it may not still work for you,but what are somethings a person can do to make a factory rod stronger?
.......................

 

[65ShelbyClone]

I guess I should have put LOL or something in the post about using a Chevy rod in that engine...I was just kidding...

Besides, that engine is just begging to have some new components made for it...look where the spark plug hole is located in the head...

I knew that, I was just thinking out loud as to why it wasn't practical. :001_smile:

A machined head with a smaller, more efficient chamber would be really cool. As you saw, the stock chamber shape is a nightmare. Maybe one with oversized fins positioned at 90 degrees to the current ones so they would get airflow mounted on a mini or kart.

hey 65ShelbyClone, can you grind and polish the con-rod beam for strengh? also can the rod be treated with something for strengh? I know it may not still work for you,but what are somethings a person can do to make a factory rod stronger?
.......................

I could try, but that would only eliminate roughness-related crack propagation. It wouldn't fix the fact that stock rods are die-cast aluminum.....only about one step up from terrible. I will say this, the rod out of my model 14 looks higher quality than any Briggs rod I've seen manufactured after the '50s. Maybe it's worth polishing....

I did some more measuring and the piston compression height is 1.480" and a bore of 2.615".

 

[Yellowhand]

Just a photo to illustrate how and why some heads lend themselves to modification, and some are a nightmare to modify...

Two stock Tecumseh 4hp flatheads...the one on the left was made in 1983...the one on the right is from 1995.

Notice how much wider the gasket area is on the newer model...the combustion chamber is also reshaped, and the spark plug hole is recessed allowing clearance for enlarging the valve size and lengthening valve opening distance. These design changes allow much easier shaving of the head to increase compression, and the alloy of the newer model is also much denser than the older one.

 

[65ShelbyClone]

That newer head has a pretty neat chamber shape. I'm surprised none of the tractor puller guys like Vogel have tried to copy it. They tend to keep the conventional valve pocket and modify the ramp.

I did some more porting on the 14 just a little while ago. The aim was to knock down the huge valve guide sticking up in the port. I figured some more work on the ports couldn't hurt. I'm happy with how it came out.

Before:

After:

 

[minidragbike]

Looking good.
I would raise the port a little higher for even more flow. But that's just me:shifty:

 

[65ShelbyClone]

That's what I was trying to do, but I was sweating about the port wall thickness. It's not much more than 1/8 to 3/16" under the big side radius.

 

[minidragbike]

This is the area I'm talking about.

The bottom of the port has the better angle towards the valve head. The port looks to taper smaller in the inside then on the port mounting flange.

 

[65ShelbyClone]

Ohhhhhh...okay. I play with cars first(ohv obviously) and small engines second. All the car guys refer to that area as the port floor because it would be flipped over in an ohv application. I just call it the short turn radius as a generality.

Does raising that area appreciably increase flow? I know it would increase the port window, but this old engine actually has a very nice sloping/curved port shape already. It's not the nearly square-edged shape the aluminum flatheads have.

 

[minidragbike]

Yes it helps a ton in flow. What I do is raise the roof of the port, but it must be at a angle. (Not just high) Then I put some epoxy on the floor around the valve guide area. The epoxy will usually direct the flow towards the port opening.

It will look something like it you had a door stop, turned it backwards, and installed it into the port. The flow will be on a better straight incline to the combustion chamber.