Briggs & Stratton, the way it should be

[Roger S]

There are some aftermarket performance parts out there for briggs and other engines. I worked my 18hp over. A milder version of what Whipper has in the "YellowJacket". If someone has a link to his 50hp video I'd like to see it.

[whipper-ag]

50hp Briggs

hey roger
There is a link to a video clip of my 50 hp Attex. If you go to the Attex Springer thread & view the pic dated 7-18-07, it's a picture of me lifting the tire up & down. Now if you click on the photobucket @ the top of the picture, it will take you to my photobucket album. Click on view album & look @ any videos I have posted. Look @ the Speedworld videos. Check them all out, they're pretty cool . Do you know Al Hodges?

[Mike]

Roger, that sounds awesome. Thanks for posting that video. What kind of mods did you do to it and what kind of exhaust are you running?

[mightymaxIV]

That Briggs sounds absolutly awsome! What did you do to it? Does it give the machine any more top end?

[hydromike]

It think I've watched Roger's videos the most out of most videos on the net. I can't get over how cool it sounds. I imagine the giant straight pipe coming out adds to the effect considerably.

Both Roger's and Whipper's (to a somewhat greater extent) make my dinky 26 EFI Kohler seem like child's-play. I wish I could do a bunch of the same mods, but with the computer controlling the whole thing, it'd end up getting tricky. I don't know if the learning algorithm in the ECU could accomodate compression changes, bigger cams, rockers, etc.

I don't know if the Kohler Twins have as much of a performance following. Perhaps it's time to build a big Briggs?

~m

[Roger S]

Found the videos Whipper! They're completely Awesome! Everyone needs to look them up.

I called Al Hodge last Fall when I was getting educated about what was available for the briggs v twin. Found some other sources and a shop that could grind a cam less wild than Al's for my slow trail use.

Timothy Schotanus and Matt Oxender built/bought engines years ago. Matt bought some kind of screaming stroker engine from Al and installed it in a customers maxII, also had a complete engine from Al in his Bigfoot. Tim has a very clean and healthy maxIV with a modified 23hp block he built.

The above video, I had a header and 7 ft straight exhaust pipe. That's why it sounds like a trumpet. The stock exhaust killed 1/2 the performance gains I got, and I hadn't had time to figure out how to fit a decent header and muffler in the limited space the argo has under the hood.

You can get different engine output depending on what you build. Tim retained a stock cam and I assume he has gobs of low and mid range torque. My 18 block has an extended rpm range and a broader power curve, where a stock engine will level off around the govenor/3600 rpm, mine will pull hard to 5000+. So yeah you can get more top end speed, but the torque is what I use in the boonies. Too much speed and you end up like Whipper, with the tires lacking contact with the planet Easy to see the need for his suspension. And Whipper's is basically a drag strip engine. The Hodge cam is too wild for slow trail riding at 2000 rpm in a 1000+ lb vehicle. Sure sounds sweet, though!

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This is an exerpt from the guy who taught me.. he's a certified briggs master mechanic, and races riding mowers. Had a 40hp out of a 18-20 hp block, which is their class limit:

I have built and raced 3 twins in my racing career. A Vanguard, and intek and my latest a Tecumseh. The Vanguard was my bread and butter. This motor was designed and built to race and be the bread and butter for Briggs as a work horse. Anyone can bolt goodies in and have a 33+ hp motor with no port work. And if took care of it does not break period. It is hands down for the money the most dependable easiest to build motor out there for racing. It revs QUICK and hard and I have turned them 11,500 rpms by accident mind you and it lived. My first motor Mowed 2 years 5 6 days a week non stop except for service. I know it was bought and serviced where I worked. Then I raced it stock with out refreshing it for 2 years finishing 5th in points nationally the second year. Then pulled it apart still not ringing it simply adding cam rods roller rockers and head work I raced it two more years. Then rebuilt it and sold it two years ago. Still running in Florida to this day. And will still run with the best of them. NOW the Tecumseh Thunder twins. The Tecumseh simply put is a brute torque monster. When built right its the best of both worlds the bottom end torque and top end HP. It will pull like a mule from 2000 to 8000 rpm. Well lets say mine will. And yea Bert kringes when I hit 8000. I tend to keep it 6500 to 7200 but 8000 does come around sometimes. While I am a briggs man always will be, I love the Tecumseh twin. While every motor has it own paticulars like this has good bottom and no top or its pretty even all the way across but just not what it needs to be or no bottom and all top end the Tecumseh built right is all of it rolled into one. Again key is heads and its the only motor out there with a dual carb setup. That is worth its weight in gold. And as good as my motor is. Like Bert said we have only begun to scratch the hp potential of these motors. In my opinion the tecumseh is the Hemi of the lawn mower motors. LIKE it or Not. Thats my opinions. And I have built as many of them all as most out there. You never know when you are running against one of my motors. I don't do it for a living nor want to I simply do it because I enjoy doing it. And those in the know know what kinda HP I put out. But thats a different story altether and not one I will get into here. Thats my two cents on the different motors.

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Here's a couple of threads at route 6x6 we talked about briggs performance if you have time to kill:

Route 6x6 Discussion Board: Rev kit - anyone install one?

Route 6x6 Discussion Board: An open discussion on engine performance

[Roger S]

Hydromike, go to heymow.com - Lawn Mower Racing Forum - Index kohler forum and ask what's available for your engine.

Note to all: this is a riding lawn mower racing forum, and they have been trying to clean up their site to get sponsors. IE, stopping all the kids asking unsafe question how to bypass the govenor and drive their mower down the street with straight pipes. I don't talk 6x6 over there any more. It is all in the archives however. They want to keep discussion within the natonal rules. So if you ask, "how can I bolt dual mikuni's on my briggs" a moderator will ask what rule set you are racing under, as only stock appearing intakes and carbs are legal. Professional engine builders are welcome and I've seen some tractor pulling discusson in the kohler forum. So maybe ask, "I have a non mower application horizontal shaft kohler etc. At the very least you should find people or links you could contact outside of the forum for parts and info.

[Roger S]

I guess its' ok to post your album page link, Whipper? If not let me know. That is some sweet stuff.

whipper-ag - Photobucket - Video and Image Hosting

[micmac]

Roger,

Thanks for starting up the engine mod thread. I'm in the final stages of building my exhaust it should be finished today. I'll post some pictures and a full write up when I'm done. Your right about the exhaust being a big issue and a big performance gain! I'm still planning on doing the internal stuff from parts I'll purchase from George H. from E.C. distributors.

One question : I plan on doing the buildup in steps are the head gaskets a one shot deal? I.E, if use the thinner gaskets and then pull the heads off later for more stuff will I need to buy new gaskets?

I dropped the Mikuni idea. George recommend the dual barrel carb and intake from a 20hp vanguard instead. I might do that down the road if I find one cheap

Mike M

[Roger S]

The head gaskets.. usually a one time thing, I have used copper shim gaskets on a harley, they said I could put them in the oven, anneal them and re use. Briggs makes a .040 composition and a .010 shim steel gasket. Both are one use. E.C. has some kind of thin gasket that holds up better under very high compression than the OEM. My understanding is briggs went from the thin to thick gasket at some point/year model. I could guess it was to lower compression for cheap gas.. could be to maintain combustion chamber volume as they bored & stroked the vanguard from 14/16 to 18/20. Maybe they did that with cylinder head chamber size 'cause I think the 14/16 chambers are smaller. Briggs includes both thick and thin in a gasket set. Why not try a small engine shop and see if they have a free set of the thin shims laying around..

You may spend some $ on the little 16 but at least the rods, valve train and exhaust would transfer over to a 18/20 block someday. It'll run good even with the one barrel. The compression, cam, minor port work, fuel, timing, exhaust, valve springs and re jetting really wake the thing up.

Looking forward to a pic of your exhaust.

[whipper-ag]

Roger
I've got a little more than a drag strip motor, When I talked to Al Hodge, I told him what I was putting it in, and what I wanted it to do. I don't know what cam he put in it, But I can idle @ 2000 rpm trail riding all day, no problem, but when I put the hammer down it's bye bye. I've got the best of both worlds. It never over heats or loads up. I'm extremely happy with Al's work. Last time I talked to Al Hodge he was working on a turbo V-twin, have you heard any thing about that? I'm ready for one!

[Roger S]

Havn't heard anything about a turbo twin, Alan, but I don't keep current with him. How does the drivetrain stay together in that Attex? Much less a turbo version That is one haulin' machine, can't stop watching the 'doughnut' video. And the suspension work you're building looks first class.

My comments about his cams.. as far as I know he only had one profile. Matt's Bigfoot had a 18/20 hp block Bandelero engine and it didn't have enough low end to make it up into the power band. Al sent him a stock cam as a replacement. But that was years ago. A 23 has a lot more going for it to start with. Al Hodge has one componenent that all hard core guys need. Billet roller rocker arms. The Vanguard has a few weak components, being built as a stationary workhorse to run all day @ 3600. Replace them, drop in the good stuff and hold on!

[micmac]

Roger,

Well I had spoken to G.H. and he mentioned that the 16 might actually be ok because from what he saw from the videos you sent, he thought that a shorter stroke engine would work well. I'm not sure I understand what he meant by that could you explain? Anyhow I decided to play around with the 16 for the reasons you mentioned above about everything transferring.
Also I assume the engine is lighter than the 20 hp so if PSI on the ground is being considered that would be a plus(I wonder when Fred S. will find this site!).

I will not have the exhaust finished tonight I went to pick up some clamping collars for the RLV silencers I had ordered but they won't be in until tomorrow.

I did dual exhausts with 1' O.D. pipe for 16 " then opened up to 1.25" O.D. for 12 " to exit the machine. I did a preliminary test today and with the silencers it has a nice rumble without being obnoxious. Kind of like a mini Harley! It definitely is a power improvement.

Mike

[Roger S]

Oh you are going pro, with the RLV stuff! If you do take the heads off we'll clean up and blend the ports and valve pockets.

I sent George some Badlands footage so he could see what his student did.. his comment:
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"I am covered up but I did lay down on the sofa and watch it. You guys are insane. Looks like fun. You can hear yours in the background just a ripping away. Dang sure sounds good. Whats your buddies think. I REALLY ENJOYED it myself thanks alot.

George Herrin
BTMRA President
2005/2004 BP National Points Champ
2004 National Driver of the Year
2003 SP National Points Champ
Herrin Mower Sports Racing Team/Fat Boyz Racing


"Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming . . "WOW ---What a Ride!"
-------

Wonder what he'll have to say about Whipper's video

[jpswift1]

I have a lot to learn about 4 stroke Briggs performance engine, but I would like to thank you guys for posting up all this great information. I would love to tweak my 18HP Briggs a little bit in the near future. I might also consider using Vanguards in more of my machines. I have a Briggs flat twin in my Hustler, a Vanguard in the Maxes, and a 440cc two stroke JLO/Rockwell in my Attex racer, so I have a variety of motors, but if I will be a lot of reading about building up these Vanguards.......please forgive me if I ask a lot of questions about this because Im new to the 4 stroke performance world. Thanks!