14 hp Briggs, performance parts or replace?

[Roger S]

If you're mechanically inclined and have more time than $, the vanguard is a fun project. It has so much potential, I was really surprised. A few budget mods would be thin head gaskets and a decent exhaust, richen the mainjets a tad. Set the govenor to 4000. Advance the timing a little. Run 91-93 octane. Could also shave the heads a little. The stock compression is around 8.5. You can also put smaller chamber 14-16 heads on an 18-20 to get the compression up. Beyond that, it's time to liberally start throwing hundred $ bills at it.

[goldhunter_2]

be carefully on the compression we deal with that on the airboats all the time once you go over 8.5 or 9 to 1 they heat up and hard to start until the engine cools off or higher compression you need to run a AV gas . with a little research he could probally also stroke the engine

[Roger S]

If you have hot cranking trouble, it's the stock briggs starter with magnets instead of field coil windings that's the problem, the magnets get heat soaked and lose it.
Briggs makes a real starter and steel ring gear to match. I'm surprised you guys have trouble cranking with a stock cam. Usually replacing the cam and losing the built in compression release is what forces the starter upgrade. I run around 10 to 1 and the guys I know run 11 or higher.

[james8719]

After trying out the stock 14 Briggs, here is what I came up with; the 14 is a good motor and has done what I asked of it. The problem is, when you add more weight( passenger and gear), it just doesn't have enough oomph. I am adding a winch, roll bar, and windshield so I want more HP and torque. I contacted George Herrin and he suggested billet rods, heavier valve springs, stronger spring retainers, a cam and remove the governor. I have the new parts on hand and the engine is getting an upgrade. George said the engine should produce 30 hp.

I couldn't bring myself to spend $1500 on a bigger engine and then drop several hundred more on building it. I will have $500 in the upgrade. I will keep you posted on the results.

[jpswift1]

Hey James, sorry if Im repeating someone's previous post, but you could simply purchase a 16HP Vanguard carb off ebay and get 2 extra ponies for a very low cost on top of it. I bought a very low hours 14HP Vanguard off ebay at a really good price and I upgraded the carb to a 16HP carb right away (since both the 14HP and 16HP are the same 480cc displacement) Im putting it in my green Attex. That machine isnt very heavy so Im hoping it will be powerful enough for what Im looking to do with it. Also, what kind of machine is your 14HP Vanguard in? Let us know how those performance parts work out for you, Im interested to hear about it. You could also try changing the clutch spring in the driven clutch on the T-20 for more usable engine RPM's in the low end. Take a look at that post. Hope this helps.

http://www.6x6world.com/forums/trans...h-springs.html

[Roger S]

I guess we'll see what the "little engine that could" can do

Did you buy the longer rods or the standard length?

Did you talk about head work with George? If not I can line you out on some simple port cleanup and blending. Which head gaskets will you use? I have the 1 barrel carburetor off my 18 that's been rejetted I could sell.

If you end up tuning your clutches, I'd work on the engine clutch, not just the one on the trans. The max is different than the argo, but in general I had to lighten the weights in it to let the engine get up into it's rpm power range. IE, stock the CVT limited rpm to 3600 or so as it "geared up".

This little 14 will just be waking up at 3000, and will turn 6000 without breaking a sweat. In fact George has over revved his vanguards a couple times over 10,000.

Also, the cam, rods, valve train would all fit in an 18 for future endeavors.

PM me if you have any questions.

[james8719]

My machine is a Max II. I went with the standard length rods. The factory head gaskets are the thick ones so I am replacing them with the older style thin gaskets.

I didn't discuss head work with George. My lawnmower mechanic use to build and race jr dragsters with his kids and he is going to replace the parts for me. He said he was going to slick up the ports and brake some edges. He honed the cylinders, and refaced the valves and seats. He is only charging me $100 for all of this.

George told me about turning 10,000 rpm in a Vanguard. He said that I should be able to run 6,000 rpm for extended periods and hit 7,500 without hurting the engine.

I have not considered the torque converter or clutch. What should i do with them?

[Roger S]

You can try the clutches as is. It may have enough power to suit you without "re gearing" them. But the only time you'll see any higher rpm is after the machine has run out and continues on a longer straightaway. And you'd have to get a max clutch guy in here to tell you how to mod the engine clutch, as the weight mechanisms are different than the argo I played with.

Tell your mechanic to leave the D shape in the ports, he sounds competent..

A header and straight through muffer will help, sort of a time consuming ordeal for some of us. Whipper should have it down to a science for the max II, after his recent bout of perfectionism.

[jpswift1]

Im dont know very much about the weights in the drive clutch, but as far as the exhaust goes, take a look at this article published by forum member micmac. He did a really nice job making a dual exhaust set up on his Max IV with this "build it yourself" kit.

http://www.6x6world.com/forums/aatv-...-vanguard.html

[budresiew]

Watch those clutches. You know the Briggs model drive clutch on a Max is only rated for 5000rpm MAX! Ever see a drive clutch come apart at high RPM? I've seen it on my buddies snowmobile when we were running across a field. Not something you want to be around. You need to address the entire engine and clutch system when you're talking more hp and rpm.