'Horace' the speedway 1600 sedan returns to Nowra Speedway Saturday 5th January at 6pm , with Ben Ford at the wheel .
'Horace' has undergone a major rebuild for the 2013 season with details to follow soon......
Horace has been sitting idle at WPVW for nearly 2 years whilst we have concentrated on drag racing , hill-climbs and super-sprints ......
The engine in Horace has been stripped down for a full rebuild in the attempt to gain more power from the 1641 NA engine . Last dyno session it produced 93hp @ the wheels , and I am now looking for 100+hp .
The Scat crankshaft is linished and a new set of alloy Pauter Pro-series conrods are to be used .
2 years ago Ben Ford was at the wheel of Horace when an inlet valve broke while the engine was turning 7000rpm ...... the damage was fairly substantial with a valve going through the piston , massive damage to the combustion chamber & valve seats , and the valve stem came back up the inlet port ( punching a hole through the inlet manifold )
the cause of the broken valve was due to an inlet valve guide coming loose in the head and as it shuffled up & down it wore the hole in the head (where it is located) so badly that the valve was coming down crooked into the seat , which in turn stressed the valve and snapped the head off .......
the bottom end is assembled and a piston is fitted to 1 conrod to check the deckheight .....
the new Pauter conrods look half the size of the piston that is attached to them , I dont think the conrods will be the weak link in this little engine
the cylinder head is welded , machined & new valve seats installed along with new valve guide
porting then starts around the chamber & in the ports
the ports are all cleaned up , the chamber is refaced and the head is ready for final seat cutting
note the spacers used in the chambers.... these heads with 42mm inlet & 38mm exhaust valves were previously used on a speedway midget which was bored for 94mm barrels . I had to have spigot sleeves made to locate the 87mm barrels into the heads for the 1641ml engine
Craig Torrens wrote:Compression must be bloody high with combustion chambers like that !!
yep Craig ..... when we made 93hp@ the wheels the compression was 11.4 , now I have set it to 12.5 👍👍 that should make great power with the right tune .....
reub wrote:Crazy con rods...
May I ask expected redline?
sure reub , you guys should know that I have very few secrets and love to share info with you ( thats why I always seem to get myself in the shit ).......
Horace is geared so that when Ben comes out of a corner the engine is turning 5800rpm and at the end of the short straight approx. 7800rpm 🤪🤪
the spark plug hole is re-drilled and the seats are refaced in the heads . I then lap each valve into its seat and check the valve face & seat face with bearing blue to ensure a perfect sealing surface
I then gap all of the piston rings , installing them into the barrels to check the end gap .
the total seal piston rings are then fitted to the pistons
all of the ring gaps are staggered , the pistons are clamped in the ring compressor and then all of the pistons are installed into the barrels , ready for assembly
valve spring shims are installed , a new set of Bugpak dual springs with chromoly retainers and hardened keepers is used , then the heads are assembled ...... ready for installation and checking piston to valve clearances
after calculating the compression ratio at 12.9:1 , I have decided to install a set of .020" barrel shims to bring the c/r down to 12.5 .
the pistons and barrels are installed with Berg circlips and hi-temp silicon sealant at the base of the barrels
windage pushrod tubes are used to limit the amount of oil that surges to the rocker covers when cornering and sliding sideways . the under-barrel air deflector plates are also installed
