18 HP Vanguard Question

[Roger S]

My engine is 10 years old, imagine they're the same, but just a guess. I bought a spare pushrod and rocker to carry on the trail. The rockers have been known to break in race situations, aggressive cams and higher rpms, more so than our milder demands. $300 for roller rockers will buy peace of mind. I have not done that and have thrashed mine hard for 18 months with stock rockers. But I now have the spares under the seat in case something happens on the trail. My #'s are

pushrod 691836

rocker 807323

[fulleraviation]

Thanks Rodger.

RI called me back with engine model and type numbers. Called the B&S dealer and ordered the parts.

Believe it or not according to the parts breakdown the exhaust pushrod is aluminum and the intake is steel. Goes against logic to me, but what the hell. I told the guy I want the part number for the steel.

Guess we will see when it comes in..

Boy I sure would like to have a parts and maintenance manual.

Rut

[Mike]

You should be able to download those manuals directly from Briggs and Stratton here: Operator Manuals, Illustrated Parts Lists & Wiring Diagrams - Briggs & Stratton as long as you know the model number.

[Roger S]

Who knows.. the aluminum in the past were for intakes, mine were and that's all I've heard of, but maybe something changed. The briggs manuals have been wrong before, a diagram showed the wrong install direction of splash oiled connecting rods in the flat opposed twin engines, causing a lot of rebuilds to be put together wrong.

[fulleraviation]

Thanks Mike,

Since I got the model Number 356447 and type 0211, I was able to download the parts manual for free. Page 26 does show that the exhaust pushrod is aluminum. Go figure. It will be changed sooooooon.

Thank you too Rodger for all you help.

Rut

[Roger S]

Lance mentioned "rev kit" in the red spring thread so I got to typing, and put it here.

Here's a refresher on what a rev kit is: Something marketed by performance v twins/al hodge. Stronger pushrods (briggs uses aluminum on one of the pushrods), valve spring retainers, spring shims for the stock springs, and a thinned flywheel key to advance ignition timing. The "rev kit" was designed for one of the vanguard class racers that doesn't allow aftermarket valve springs. It's fine for a stock cam, although pricey, as it minimizes spring pressure on the stock rocker arms and will still keep the valves from floating with a stock cam, like from 4 to 5 grand.

However, if you put a real cam in it, the rev kit is worthless, as the stock springs are not enough near 5 grand and beyond. You may not run over 5 on purpose, but it happens and it's important to set the exhaust valve down gently on it's seat since it's red hot.

You don't need the billet trinket al hodge pushrods when steel vanguard pushrods for a couple $ will run 8,000 rpm and never fail. George at E.C. Distributing will set you up with double springs and retainers for far less $.

Rutledge, running near 5 grand is getting up there for stock rods, not much of a cushion. Your hard cranking may be too much clearance on the exhaust valve lash, as it would degate the function of the steel ball sticking out of the heel of the cam lobe to hold the valve open during cranking. Did you move the piston down the bore a 1/4" past TDC when setting lash? If you don't, you'll be setting lash on that ball, = no compression release.

If that doesn't work, take the starter apart and clean the grooves between the commutator segments and put brushes in it if they're worn crooked. Lube the bushings, too. My starter wouldn't crank mine hot, (cam w/no compression release, long rods), but after going through the starter again and setting lash to .005 ( I had been running more clearance for torque) it has been starting well. Also, the duration of an aftermarket cam will give you a little "compression release" effect. The only real cure for a "never have to think about it again" is a different flywheel w/ring gear and a real starter for $250 ish.

A couple of my friends with frontiers are having sluggish cranking on their 23's. They sound like weak starters/batteries, etc. George says the #1 cause of hard cranking in the vanguards is excessive valve lash. Have to keep in mind the "easy spin" briggs starting is built around an undersized, low amp starter, meant to be cranked by any half charged lawn and garden battery, depending on the exhaust valve being held off it's seat at below cranking rpm by the compression release. The compression release is a work of art, however, very neat design. There is a spring on it that can fail, causing the comp release to not work. It's not common to fail on vanguards, but is on some other briggs engines.

I would also think twice about not using the long rods. A cam will take some static compression ratio away. If you drove my 18 I think it'd convince you. It is long rod/shaved piston and thick gasket. You can boost pump gas with a lead additive, just carry a quart of it with you instead of hauling AV gas around. You'll never make any power at 8 to 1 compression without going to a bigger engine or forced induction. Well, that's my opinion, not fact. Run the idea by George. To get carried away here, you could do the long rod/shaved piston/flat top, and put 23 hp heads on it with bigger chambers to lower the compression. Then you'd need a different intake manifold.. which would come with a 2 barrel George prefers to go the other way, put smaller chamber 16 hp heads on the 18/20 blocks. With a thin gasket and shave the head about .040 He says compression makes torque, and he likes to build the vanguard for torque, rather than rpm. The 23 heads would be an rpm engine with it's ports, but there's no way to get the compression back up.

[fulleraviation]

Roger,

I do have the EC Dist. double springs and retainers installed. Bought 2 more stock steal pushrods and thin head gaskets. I have checked the valve lash several times with a 1/4 turn past TDC. I have not noticed any difference from TDC to 1/4 past. Have even check with one valve open then checking the other. I will check some more.

I actually think my starter might be hurting. Good point on this. I can recall several times hitting the starter and it just clicks and about the third time it turns. Another project.

Soooo, with the above items installed you would say that I am open for a cam, long rods and shaved pistons now. Right? Not to mention exhaust work.

Hey thanks for the input,
Rutledge

[Roger S]

Yeah, you are ready. The upper part of my post was for other peoples info, not yours.. I'm not so forgetfull that I forgot what you've done so far

I'd add some basic head work, just port blending and radiusing.. you can send them to George if you don't want to do it. You WILL feel the next mods, in a major seat of the pants way

Will need to lighten the weights in the engine clutch just a tad to let it rev; your max clutch is different than my argo so I don't have the details.

[fulleraviation]

Just got done riding again to get some numbers to post on another thread. I am happy right now with the power that my 18hp engine is making and putting to the ground. What I would like is my current low gearing with more top speed.

I thought that running more rpm's was the way to obtain the extra speed that I wanted, but found that at 4500rpm I only go 2 mph faster than at 4000rpm. I also thought about taller tires, but that leads to other issues. Right now my top speed is about 22 mph with 3psi in the super terra grips. I am sure I would be faster with 9psi on the road. To bad we couldn't adjust tire psi on the fly.

Any ideas are welcomed

Rutledge

[George]

Is there anyone on the site who can take a measurement off either a 16 or 18 hp Vanguard?

I need the distance between the screws that hold the pull-start recoil assembly to the engine. I need the distance between a catty corner pair. I believe that there are only 4 screws so either pair would be fine.

Thanks.