Testing at Forrestburn

List of development issues this year

The Monklands Sporting Car Club (MSCC), my local car club have an early season event called a Car Trial. I used this to test out my winter modifications. The car is still in it's early stages so needs to be proved and what better way than to enter it into a car trial.

1) Gear Change:- After adjusting it correctly, the clutch is definitely fixed, no dragging issues any more. The gear change 1-2nd is clunky no synchro but I suspect that is normal..

2) Battery drain:- This eventually made me give up the last event see: battery-drain-problems. The electronic timer modulator on the water pump is working a treat. I put it in a sealed box now and wired it in permanently (out of sight) it comes on with the ignition now (in case I forget). No overheating problems despite a 80% off 20% ON. The timer box can be removed quickly if necessary. I will order a spare battery however as the frequent stop starting on an event will still drain the battery down. It will last till lunch time then change it over if necessary.

3) Fluid Leaks:- The latest water leak from the engine is now fixed, a friend  helped me remove the side alloy casting, trued it up on the belt sander, made a new gasket and refitted.

4) Choke:-  Fitted new choke cable which makes putting the choke OFF much better as the core is piano wire and it positively returns the mechanism. Putting it ON is the same faf, I would need to design some sort of external leaver accessible when the bonnet is on.

5) Oil Gauge:-  Fixed the oil pressure gauge, it had a leak in the pipe at the gauge end letting in air on switch off.

6) Steering:- Improved the steering range on heft handers by cutting the floor away in the driver foot well.

7) Reduce the clevis pin size on the brake leavers as the are fouling the suspension on full lock

It now drives more like a normal car for the first time. The brakes are even improving in effectiveness due to getting more running but the binding issue has not gone away.

Inside foot well modification

Steering arm more clearance
 

New clevis pins

Still to do

* Fit lights

Here is an Index page for the build

Battery Drain problems

I used a modern core to modify the radiator in height, and as such removed the ability to completely convection cool the engine as the frictional loss in the vanes of the new core is too much. A new honeycomb core was way too expensive for my taste (£400 quoted). Instead I decided retained the modern core and added a 32mm electric pump from CBS instead.  Unfortunately the battery drain is 8 amps and that flattens the motorsport battery in no time unless you are in charging mode 30mph.

If I used a motorbike pump (less drain), due to the reduced bore, it would reduce the convection cooling even further. The CBS pump although very efficient is 80% redundant, it is only required to give a bit of extra circulation now and again.

The answer is simple, modulate the pump power at a ratio of 1:5 where On = 2 seconds and off =  8 seconds. This will reduce the power consumption by 80%. I found a Velleman 555 timer project kit in Maplin that will do the job just fine. However when I connected up the said kit it initially worked fine but on starting the A7 engine the times became random. I added a low dropout LM317T regulator, two resistors and a capacitor. This cured the problem and for good measure I put the whole thing in a waterproof/RFI enclosure. Again for good measure I used some capacitive feed throughs to connect the power.

Velleman project board with regulator

Waterproof/RFI enclosure

Update 4th Aug 21

This problem has been eliminated by the addition of an Alternator. The pump is now permanently connected via a thermostat mounted in the pipe to the top of the raditor.

Here is an Index page for the build