Briggs & Stratton World Formula
In 2003 Briggs & Stratton Motorsport division introduced the world formula racing engine to meet the rules as set out by the CIK.The World Formula Briggs & Stratton racing engine is built of the successful Animal platform with a redesigned cylinder head, larger lift camshaft & valve springs, different intake manifold design, larger carburettor, electric & pull start, billet conrod, larger clutch & rpm limited pvl ignition.The world formula was designed with low engine maintenance in mind & an affordable race engine package. Every World Formula Engine is assembled by hand in the Briggs & Stratton Motorsports Milwaukee Factory by highly skilled & trained technicians.
BRIGGS & STRATTON ANIMAL OR BRIGGS & STRATTON WORLD FORMULA
Very often people think that bigger is better and the Briggs & Stratton World Formula has got to be better than the Briggs & Stratton Animal. Depending on the type of racing you are doing both engines have there place. The World Formula is a race engine that needs to make the revs to produce torque and horsepower. For this reason the standard clutch setting of the Titan clutch supplied with the Briggs & Stratton World Formula is set at a high rpm engagement speed. Below are some comparisons of both the Animal & World Formula engines.
The World Formula runs a higher lift camshaft with more duration and produces its torque higher in the rev range, the valve size is larger in a World Formula cylinder head than an Animal cylinder head and the intake port is also bigger on a world formula. The Intake port of a World Formula is a different shape to the intake port of an Animal. The carburettor on a Briggs & Stratton World Formula uses a PZ26 Walbro, the carburettor on a Briggs & Stratton Animal is a PZ22 Walbro.
The number after the PZ?? refers to the bore size of the carburetor, larger the number larger the boreBRIGGS & STRATTON PVL IGNITION COLORS & RPM LIMITS
PVL ignition limited to 7100 RPM on a World Formula PVL module is red
The Blue PVL ignition module is RPM limited to 12000 RPM on Animal
The Local 206 uses a Green 6100 RPM limited PVL module
Junior PVL & Junior carb slide available for Animal Rev limited to 4100 RPM & uses the Black PVL module
Animal has a squeeze cast conrod, a World Formula has a billet CNC machined conrod. World Formula is supplied with an electric on board starter & recoil starter & requires a 12v battery. Animal is supplied with a recoil starter only, due to the higher camshaft lift the world formula may require valve springs to be replaced compared to an Animal. World Formula uses a cast aluminium curved intake manifoldAnimal uses short pressed steel carb spacer. World Formula is supplied with a header pipe to match the power level of the engine out of the box. In Short both Animal and World Formula Engines are World class thoroughbred race engines and depending on the type of racing you are doing will depend on the the engine you need. The Animal can be modified and parts from the World Formula do interchange with the animal. When the world formula is fitted with the blue 12000 rpm coil the engine will rev harder, the extra strain put on components is far more than at lower RPM so the harder you rev them the shorter the life span of any engine.
Every one has a different opinion on this but this is what we have found.
Dont use oil additive like Teflon based engine treatments as they are designed for mostly water cooled engines with oil pumps. Stick with an oil designed for splash feed air cooled racing engines we have had good results here in Australia with the Redline 4 stroke kart oil and you dont need to add any additives. Never use synthetic oils designed to be used in water cooled 4 stroke engines.These oils are designed to not run at the extreme temperatures that & air cooled engine can run at & also most of the water cooled engines are fitted with a oil pump that pumps oil through the engine & doesn’t rely on the dipper on the conrod to splash feed the oil to the engine.
Briggs and Stratton Racing Engines require around 600ml of oil to fill the engine block, when using an angled engine mount the engine may hold a little more than when running the engine flat.A quick method of checking to see where the oil level is is to remove the oil plug in the side cover of the engine with the rear axle of the kart raised & you will see the oil sitting at the internal thread of the side cover.
NEW ENGINE RUN IN PROCEDURE
When it comes to the first time fire up of a new Briggs & Stratton racing engine this is the procedure we use for the break-in period. Briggs and Stratton World Formula engines are air cooled engines & use a splash feed oiling system.Your World Formula racing engine is hand assembled & uses a Teflon coated skirt on the piston & a special developed cross hatch finish is used on the cylinder bore so with the correct oil the engine is ready to race after a break in period.
Careful preparation & taking the time to learn how to set the float level,carb mixture & idle speed & making sure every thing is tight & secured you have added oil & got the fuel up to the carb & you are ready to bring it to life.Briggs & Stratton racing engines are fitted with a chokes & should be used for cold fire ups. We always loosen the rocker cover bolts slightly, the reason we do this is once the engine fires & you see a tiny drip of oil coming from the rocker cover & cylinder head joint you know that the oil is at the top end of the engine & the valve train is also being lubricated. Shut the engine down tighten the rocker cover bolts & follow the next steps.
RECOMMENDED BRIGGS RACING ENGINE RUN IN PROCEDURE
We fill our new engines with 600ml of Redline 4 stroke karting oil get it started & run the engine for around 10 minutes with no load DO NOT HAVE THE CHAIN CONNECTED TO THE CLUTCH & REAR AXLE WHILE REVING THE ENGINE EVER. Take the engine to around 2000 rpm varing the rpm from above idle to 2000 rpm. You can divide the run in with 3x 3 minute runs , Try not to let the engine idle as it is important with a splash feed engine keeping the revs up above idle will get the oil slinging & splashing over the moving parts, cylinder walls & the engines valve train. If an adjustment needs to be done switch the engine off make the adjustment have a quick look at the oil level through the filler plug the restart & continue the first break in period. After this first stage let the engine sit for 5 minutes for the oil to return from the top end of the engine then while the engine oil is still warm drain the oil. This first drain should remove any material from the cylinder walls or bearing material from the internal rotating assembly of your gokart engine. Refill Your Briggs Racing Engine with Redline 4 stroke go kart oil or the oil you have decided to run, fit and tension the chain restart your engine & get it out on the track and run it around for about 15 minutes vary the engine speed and always keep the revs high enough to keep the clutch engaged. Keep your Briggs World Formula engine below 5000 RPM for this second part of the engine break in. After you have done around 15 minutes of driving time its time for another oil change, let the engine sit for around 5 minutes drain the crank case and refill the engine with another 600ml of oil. Depending on the way the engine is fitted to the kart and the engine mount used we have found some engines can run less than 600 ml. Once your engine is refilled and you have checked over your engine that the exhaust is not leaking & the nip up the nuts on the manifold your Briggs and Stratton World Formula is ready to race.
The Briggs & Stratton World Formula has around 12 horsepower out of the box has a electric on board starter & is a TAG engine
Small Engine Performance offer the full range of AussieSpeed Small Engine Performance Products & Dress up gear for World Formula, Honda GX, Briggs & Stratton Vanguard & Subaru racing engines
Walbro PZ26 World Formula Carb set up & Tuning
Walbro PZ26 Briggs & Stratton World Formula Carb mixture screw position.The mixture screw on the world is located under the fuel bowl on the inlet manifold of the carburettor.
The PZ26 Walbro Carburettor that is fitted to the Briggs & Stratton World Formula engine is a very easy to set up & tune. We advise customers to take the time to set up the float height on the Walbro carb. Small engine performance offer an easy to use float gauge to set & check the float position on World Formula carburettors.
The float tab pictured is the only internal adjustment for setting the float on a World Formula engine. Be careful when bending the tag that you do not bend the actual float it self. The needle valve hangs on the float height tag. Bending the float tag towards the body of the carb raises the float level while bending the tag towards the float bowl lowers the float level
The red pointer is positioned on the needle valve. Be sure when setting the float height that the needle valve is not compressed into its seat. The Float height on the World Formula needs to be set at 14mm or .550 thou of the body of the carburettor where the float bowl attaches to.
The float drop is not critical in the PZ26 Walbro World Formula carb, it is a very good idea that the height tab for the float drop is set that the needle valve is set to low as the needle valve can drop out of the seat.
World Formula Aussiespeed engine dress up kit in wrinkle black available as single components or complete packages