We have to remember that WF was born for a very different concept that unfortunately never took off. Its birth place was Europe, at a time when CIK thought 2 cy engines might be endangered. The concept was for the CLASS to be called WF, and made up of several brands that met the design of that class. This was back when Dan Wilson was still in charge of Motorsports for Briggs and they were the only ones to really jump in, things at CIK change and the deal fell apart. altho engines were used here and in a few other countries, I believe South America was a strong place for them.
We have to remember that Animal, LO and WF are built on the same lines and share many of the same parts, Animal and LO are almost the same engine accept for jetting and ign coils. WF did have some different parts. The rod was billet altho we now use the std Animal rod often even in Road Racing. Performance wise it has a bigger cam and carb and more compression, which give it the potential for more power. The draw back here is part of the org. WF class structure was a min. time between rebuilds concept written into the rules. For that, it was given a relatively low rev limiter, I think it was around 7000. The bigger cam, carb and comp give it the potential to make power much like a WKA limited, however it comes at a higher RPM where it can use those things. The limiter shuts it down before it can take advantage of those things. As with any engine increasing the flow possibilities have a trade off, and low end suffers because of a loss in velocity at lower rpms. Below 6000, it makes slightly less power then a WKA Animal
This was all prior to the Briggs switch to PVL ign and so it was easy to disconnect the rev limiter, at which point it could really use the cam and carb and was a very strong performer, the billet rod let it live at high rpms without problems.
With the limiter intact here at Badger, 6/10s sprint track the WF and Animal turn very close lap times, Animal faster throught the turns and tight stuff, WF had the advantage on the long straight.
As I said before, here BP Animal was here first and became strong so always had the edge as far as popularity. WF was a great engine, but at almost twice the price out of the box, it just didn’t sell
As far as time between rebiulds, like most people we simply let our leak down tester tell us when its time. When valves or rings leak, its time, period. On engines raced on dirt, filters are the main determining factor. Don’t stay on top of your filters both carb and crankcase, you see us much sooner. on anything other then dirt, carbon is the problem, it builds up on valves and seats losing seal, and on piston and head, which when it washes off, gets down between rings and walls.
Regans business consists of 4 brands of 120 engines and alot of LO206 engines in sleds, all of these must run gas as a fuel. Kart engines from here are almost all Alky engines. The differance in carbon build up is very easy to see, and greatly effects rebuild time. Gas is a very dirty fuel and builds carbon, when it builds up on the ex valve, it looses seal, same as it passes by the rings. Alky is very clean, depending on oil choice it builds none to very little carbon, and need rebuilding less often.
Alky Animals usually go 2 seasons and we have 14-18 races at Badger with most people also practicing each Sat.
Honest truth is, if the leakdown test says its not leaking down much, not much sense changing parts that are working well. I never have had an issue with parts fatigue with the later versions of any of the Briggs engines