new to briggs flatheads/ is this engine worth using?

[chriskbmx]

Hi, my name is Chris. I am a hardcore car guy, mainly of the bmw types(mostly e30's for you car guys), But am lost when it comes to this engine. I want to use it for some kind of fun project, that I can play with to make more power.

Here is my problem, I Know nothing about these flathead briggs, or briggs engines at all to be honest. So I cam here with a few questions, but first here is what I know about the engine.

Model 130292 type 0709-01 code 76101307

13 cubic inches
series 0
horizontal shaft, with another aux shaft off the cam( which is really my main concern)
9 plain bearings
2 rewind starter.

So I am curious about a couple things.

What is going on with the aux shaft that seems to be off the cam? I say seems because I have not ripped it down to check it out yet. Can I still use this on a cart? If not can I get away with another cam and just welding the hole up?

Second question:
Are the plain bearings going to cause me any problems when trying to get as much horsepower out of it? When I mean as much power I mean as much as I can get out of it without spending a ton of money as this is a for fun project. I know that if I want to spin over 5k I need to replace the rod and possibly flywheel.

Third question: cams
I was looking around on youtube and I have watched a few videos where people did there own welding and griding on the cams that looked fairly crude. Can anyone enlighten me to how they get away with them being kind of crude? I am also curious to what cam I should look at getting? more on the goals though later.

fourth question:
is the carb on this thing worth anything? and if not where can I get some good information on go kart induction?

Goals
I am trying to build a fun engine just to see what I can do. I have access to a decent amount of resources and I am very good with anything mechanical.

So id pretty much just like to make the most power I can for as little as I can. Things that I was looking into doing.

Shaving the head .030 or more?
getting heavy duty springs or 2 exhaust springs?
a cam, or make my own grind if I can get some more info.
shave the hump in between the valves.
some kind of induction work
porting
gov removal
flywheel maybe?

What else should I look into doing?

Either way thanks in advance for any help!

 

[OzFab]

Model 130292 type 0709-01 code 76101307

13 cubic inches
series 0
horizontal shaft, with another aux shaft off the cam( which is really my main concern)
9 plain bearings
2 rewind starter.

Ok so, you have a 5hp B&S, one of the most popular small engines of all time; there are racing classes based on that engine.

This one obviously started life on a tiller or similar impliment, hence the aux shaft

What is going on with the aux shaft that seems to be off the cam? Can I still use this on a cart? If not can I get away with another cam and just welding the hole up?

You absolutely can, set up correctly, it can be used to give a kart reverse as it spins at half the speed, in the opposite directoin to the crankshaft.

Second question:
Are the plain bearings going to cause me any problems when trying to get as much horsepower out of it? When I mean as much power I mean as much as I can get out of it without spending a ton of money as this is a for fun project. I know that if I want to spin over 5k I need to replace the rod and possibly flywheel.

Power no, RPM YES! As you would know, you don't need massive RPM to make massive HP. The standard bearings are only rated to around 5krpm, for higher speeds, you'll need high speed bearings...

Third question: cams
I was looking around on youtube and I have watched a few videos where people did there own welding and griding on the cams that looked fairly crude. Can anyone enlighten me to how they get away with them being kind of crude? I am also curious to what cam I should look at getting? more on the goals though later.

You can try but, IMO, that's best left to the pros...

fourth question:
is the carb on this thing worth anything? and if not where can I get some good information on go kart induction?

Yeah, they're not worth much; they're a suction type carb with a small, built in pump; they work great in standard/stock config but, not too great in performance applications.

Best bet is to adapt a mikuni or honda clone carb onto it.

However, in doing that, you will need to set up an external tank as the standard tank is attached under the stock carb...

Goals
I am trying to build a fun engine just to see what I can do. I have access to a decent amount of resources and I am very good with anything mechanical.

Throw enough money at it & it's possible to get 10 times the power out of it (yes, 50hp)

So id pretty much just like to make the most power I can for as little as I can. Things that I was looking into doing.

Shaving the head .030 or more?
getting heavy duty springs or 2 exhaust springs?
a cam, or make my own grind if I can get some more info.
shave the hump in between the valves.
some kind of induction work
porting
gov removal
flywheel maybe?

What else should I look into doing?

There are bucketloads of mods & performance parts for these little killers, the lists are literally endless...

Oh, welcome to the forum

 

[chriskbmx]

So it is deffinitly possible to just remove that cam, use another cam and just cover the hole?

Do you guys have a link to what carbs I should be looking for, I have access to a couple small cc motorcycle engines, but they use cable through the middle carbs(I forget what this is called)

I was also hopping to get an idea of what mods would be best before I went hard.

Is there any high performing bushings out there I can use? or anyway to get more oil to them? I assume that is the killer of the bushings after all?

And I am no pro, but I can weld, and have access to a dial indicatior and degree wheel, so if any of you guys have any articles on kart cams I would much appreciate that.

 

[exenos]

Are you meaning a carb like this?

I know some people have bored the block out to accept sealed bearing. Might be better to look into that if you have access to a machine shop than to try to find some way to get more oil to the bushings in a slash lubed engine.

 

[chriskbmx]

yes exactly what i mean. You unswrew the top cap and the throttle comes out. if that works i have a carb of a pw80 dirtbike that might work well.

Do you have a link to boring the block to accept sealed bearings? Im assuming the same crank will work?

 

[chriskbmx]

There also seems to be excessive endplay on the crank. Anyone know the spec? Also what would cause the endplay, just a bad bearing?

 

[solomon]

End play back and forth or up and down? A carb that size is likely much too large for that engine. As for the head machine it .030-.050 AND cut a fire slot, you really want a good flow on these engines. If you plan on spinning over 5800 rpm throw a billet flywheel on it. Obviously a billet rod and once again, if your going over 5800 rpm you also need a good set of valve springs or you will be floating awayyy, good luck!

 

[solomon]

I believe there is also a DIY on here for deleting the head gasket instead of having the head milled.

 

[chriskbmx]

I will be getting the head machined for free. Can anyone tell me about the fire slot, or have a picture? How far can I rev this motor with the bushings? or is it just as easy as milling the block to fit bearings?

Also what size carb should I be looking for?

 

[solomon]

I would port the intake on your engine and then use calipers and find a carb the same size as the bore... As far as the fireslot I'll see if ican dig up a pic of when icut mine a while back. IIRC the bushing will hold up to 6k or soo. Be sure to run synthetic. What's your budget on this thing?

 

[solomon]

here is someonelses head with a slot cut

 

[solomon]

Oh, and I have an e36 myself

 

[chriskbmx]

E36 can be very cool. So what kind of power am I looking at with this formula.

with the head ill cut the head .030
Maybe a slightly smaller gasket if they make one?
Fire slot
everything nice and polished up, no hotspots here lol
a tuned exhaust
cheater 94ss cam
billet flywheel
2 exhaust springs
billet rod
block welding.

The only thing I am really concerned about is the bushings over the bearings.
Also should I get a different pto cover sense there is an aux shaft coming off the cam, or can I just change the cam, and cut mill that part of the cover and weld it up?

Another question I have, should I go with a stock rod? or can I go with a slightly longer one, and a stock piston to raise compression a bit?

 

[solomon]

I'd expect quite a bump, get dual valve springs not 2 stock exhaust springs because they will float around 5800 rpm. Yes you can stroke it with a longer rod and shorter piston. Wiseco makes them I believe. I personally would grab a different pro cover but if u weld it carefully I'm sure it'll be fine.leave the intake rough don't polish, it'll mix air and file MUCH better

 

[solomon]

*fuel my bad

 

[Poboy kartman]

I'd expect quite a bump, get dual valve springs not 2 stock exhaust springs because they will float around 5800 rpm. Yes you can stroke it with a longer rod and shorter piston. Wiseco makes them I believe. I personally would grab a different pro cover but if u weld it carefully I'm sure it'll be fine.leave the intake rough don't polish, it'll mix air and file MUCH better

I recall another post where it was suggested to port and polish both the intake and exhaust. I didn't say anything because the distance is so short-I didn't think that the fuel/air mixture would have a chance to settle.

In automotive scenarios- a certain amount of controlled turbulence is beneficial- as it keeps the A/F mixture homogeneous. .......but it has a long trip....not sure about the little guys. ..........

 

[solomon]

I've always been taught on small engines to leave the finish rough on the intake. To each there own I guess. Maybe someone else will chime in

 

[solomon]

Po'boy cartman can u please post where you got this info, I really feel it should always be a bit rough on the intake

 

[itsid]

If I may ask...
what's that with the constant double posting solomon?
You're here for long enough to know the edit button I guess

Now back to our regular program... (aka topic)

'sid

 

[OzFab]

It is better to leave the intake dull & the exhaust shiny...

As far as porting goes, the main part on this particular block is the sharp edge on the ports, where they change direction...