Steve Butts has released the details of the engine that did so well in the 2007 LOTRDC series. I have left the explanation in his own style as it ads a certain something.
By reliable I don't mean an engine which was stripped several times between races. Dave's was stripped *ZERO* times through the season.
Dave's engine uses a spec that I came up with after much advice from Dave Andrews (DVA), Dave Walker, Warren at Piper Cams, Steve Smith of Vibration Free and Bernard Scouse.
AFAIK there are only four engines built to the same spec, three in Elises and one in a Caterham.
Dave's engine started life in 2006 as a track day engine making around 233bhp/163lbft - nothing spectacular for a 1.9k but it wasn't running the best exhaust manifold or the ideal cams, but a manifold and cams that Dave got the for the right price s/hand.
Its spec was:
Scholar 1.9 block with Pistal pistons.
Standard K series crank Tungsten inserted for better balance by Steve Smith at Vibration Free.
Complete engine balance By Steve Smith
DVA ported MS1 (VHPD) head with 32.5mm inlet valves and standard 27.3 exhaust valves - *THIS HEAD WAS PORTED 8 YEARS AGO*
Piper 1227 cams
Early EBD manifold using 1.5"->1.75" stepped primaries
EliseParts SCRP and back Box
Emerald ECU
VHPD rodsIt uses a head DVA ported for me in 2000 and I sold to Dave. As part of the sale I offered to build Dave the engine.
It covered 5000 miles mostly trackday and LoT French Frolic miles, and those who drive the French Frolic will know that the driving through France is neither relaxed, slow or casual!!
Dave lent me the engine to use in the 2005 Tuner GP after mine failed in spectacular style - which got 5th overall and the fasted NA car at the event.
When Dave decided to race I said that he should change the rods (as these had failed for me) to Arrow steel, change the cam spec to the one I was using at the time: Piper 2180/1444.
Initial mapping gave 247bhp and 165lbft. Dave Walker then reduced the peak power slightly to 241bhp to allow Dave to run his car lighter and still fit in with the LoT power to weight ratio race regs, as we felt that running a lighter car was better than having marginally more peak power for the last 500rpm of the rev range.
The 247bhp/165lbft are still not as good as DVA has seen in Caterhams but not bad at all considering the head porting is very old and he has improved his head porting in the last 8 years. There is also a restriction present in the 1.5" primaries of the EBD manifold, costing around 5bhp. But as Dave wasn't after anymore peak power the money that could have been spent on the manifold went elsewhere.
Dave's car clearly had the legs on all the other class B cars as was witnessed by those watching the series. Its a shame other issues with his car prevented him from some success, but that's another story. His 2nd on grid at Donnington showed what was possible - shame the cheesium Quaife gearbox let him down in the race!
After a good season and 2000 purely race/test/qualify miles I suggested that Dave should get a power run to see what the engine was making, and if down then start investigating with leak down tests, etc.
With the mapping adjusted to that which gave 247bhp and 165lbft the car made an extremely impressive 246bhp and 170lbft!!!! Clearly it has losened a bit and made better peak torque.
Dave Walker commented that its extremely unusual for a genuine race K series to still be making that much power after a complete race season.
Dave and I stripped the engine yesterday and found nothing untoward. The valves, springs and caps will be replaced as an insurance measure and the bearings inspected for wear and replaced if required. Then it will be slapped back together for another season's motorsport
IMO the reason his engine makes such good power is down purely to the DVAPower head porting and Piper cam specification - and this power is being held back by the exhaust manifold.
IMO the reason the engine was so reliable and also kept its power for the race season was down to Steve Smith of Vibration Free for vastly improving the balance of the crankshaft by adding around 2kg of weight to the counter balances to correctly counter balance the 1.9 rods and pistons. And also the use of a Scholar block which uses thicker liners that are held in place in the block compared to the thinner Rover liners that slide into the block.
Steve Smith explained to me that a standard, VHPD or after market steel K series crank has a 1 tonne bending moment at around 8000rpm as a result of the incorrect counter balance weights - these are suitable for 1.4K rods and pistons which are lighter than 1.8 and 1.9 rods/pistons. This bending moment causes flex and vibration in the block giving rise to loss of power and reliability.
There is one poster on here who claims to be great inventor all things K series, including the crank balance, certain cam profiles etc...I'm sure he will post to try and rubbish my engine building efforts and reasoning behind why I think this engine has been a success. Dave's power runs and lack of failures speak for themselves.
I can testify that Steve Smith (along with an engineering company who did the machining) was the sole person responsible for Dave's and my Tungsten inserted cranks. I can also testify that the cam profiles were designed by Piper (one for 2.0L K series and one for 1.6L K rally engines).
As Simon Thornley would say: Nuff Said
So if you want a reliable K series to make the 240bhp LoT limit and last all season without a strip down then you have all the information you need above.
Be warned that its far from cheap and you need either a Quaife six speed syncro box or a Quiafe Ultraclose ratio 5 Speed to make a package that gives as much torque at the wheels as an NA Honda or Duractec.
There you go - even Simon Erland could follow this recipe.
