Well it was a busy start to October with final preparations for the biggest 4 stroke race of the year, the SEK 24 hour held at Sydney Premier Karting Eastern Creek.
As usual a grueling event that we chose to sit out this year but with a field of 21 karts there was barely a team in the field we haven't assisted at some point. At the end the top 4 positions were filled by karts sporting engines that have been through our workshop in the recent past.
We can't take all the credit though. The level of preparation involved in making a quick, consistent and reliable kart comes back to owners who spend countless hours preparing the complete package in the weeks prior to an event of this size. Congratulations to all competitors.
Nothing has changed after the 24 hour with no less than 12 engines in line. We would need a panoramic shot to get them all in.
4SS is heating up in NSW but especially the Sydney area with engines going out in fast succession. This past Saturday night seen 15 karts invade the Wollongong Kart Club twilight meeting, the first time the club had seen entries in this class. A sign that the 4SS Thundersport final will be a big event at Lithgow in November.
The SEK 24 hour presented the opportunity for the first real test of the new Tillotson 225RS engine. After a short test at Wollongong a few weeks back and then an afternoon of research on the dyno, we hit the Sydney venue running and the engine impressed immediately. In fact it's like no other 4 stroke engine we have driven before. While still in the final stages of development and not for retail purchase as yet, this engine package will be something to keep an eye on.
From the moment the engines fires, you know it will impress on track with a genuine 225cc of power, a specially cast aluminium block for Tillotson available in up to 76mm bore, billett rod and flywheel and the high level of engineering which is evident immediately. The block itself has been produced with additional gussets, thicker base and more material overall. This eliminates the risk of cracking blocks due to flex which is common in engines using generic Chinese blocks designed for use in power equipment. Most clone engine suppliers will recommend use of a thick engine plate to reduce torsional twist that can crack blocks or at a minimum create drag on the crankshaft robbing these small engines of power. This engine is a true engineered race engine as the pictures below will show.
The on track performance is where it gets real interesting. For true comparisons we tested on track with a variety of other 4 stroke karts. While on a marginally softer tyre (tested after the event) than those of all other karts on the day the Tillotson kart set the fastest lap of the hour long practice session. More than 1/10th quicker than the fastest twin Honda and over 2 seconds quicker than a single engine Briggs 206. Quiet impressive given the kart was dropped on the track with only a minor adjustment to tyre pressures and no adjustments to high or low mixtures. No doubt there is room for improvement. It should be noted that a Twin engine Briggs Animal TEKA kart was also in the session but no times recorded. Visually faster i can only estimate that when fully sorted, the Tillotson package would find itself somewhere between the twin packages of TEKA and SEK. Given the difference of the twin karts at this venue is about 1 second, the Tillotson package will be impressive right in the middle of the two while running only a single engine.
The engine itself is obviously making it's power quiet conservatively given it is rev limited to only 6500rpm and quiet a soft limiter that still maintains good drive while on the limiter. Other engines on the market claiming to be of similar performance are rev limited to above 7000rpm in order to see increased on track performance.
The HW style Tillotson carb is quiet rich at idle but once sorted still allows easy starting but not designed to idle for extended periods. Not a great problem considering the power at hand, you are not purchasing this engine for a Sunday drive. Such is the atomization of the carb, the inlet manifold actually ices up externally and you could easily mistake it for running on methanol. While on the subject of inlet manifolds, the smart design actually has the carb exiting out rearward rather than over the tyre as we are used to seeing. This obviously eliminates some of the water issues in wet weather but also makes the engine much easier to fit with more engine mount options to keep the cost down.
The engine in its current form is supplied with an RLV muffler, quality large alloy chain guard that incorporates a heat shield and Maxtorque 21 tooth clutch. The estimated price could well be under $2000 with a basic engine mount option which makes it quiet affordable and sensibly priced for such a quality piece.
With about 2.5 hours on the engine now, we should be testing at Picton kart track on Saturday 26th.
Thanks to Mark from EC Carburetors for the use of his photos. EC have worked closely with Tillotson over the years in development of carbs and the new 4 stroke engines.
Special thanks also goes to the Tillotson engineers that have given us the opportunity to test the first engine in Australia. It hasn't disappointed anyone who has had the pleasure to test it.
Be sure to browse the parts store as we are adding more products every week, and remember most of our advertised products are in stock and ready to ship without delay.