TRUCK MODIFICATIONS MID SEASON

One good thing happened in Germany - I took delivery of my new Detroit 60 series engine, and brought it home with me on my transporter- looking at it in the mirror and hoping it was the key to my success, all the way home!!

As soon as we got back to base the work started to prepare the Truck for a friendly meeting in Ireland, in late August.

Lots of bodywork damage for Roger to mend and the new engine to fit as we had decided to 'go for broke' and fit it into the White and try it out for the rest of the season. I couldn't wait until next year! I wanted to see what it would do now!

The last two weeks of July and the first three weeks in August were intense in the workshop, and on my wallet! Lots of parts on the new engine were different to ours, and had to be swapped, made or modified. The hardest job was the clutch. We ran a 15" twin plate, which used to slip a bit under load. The new engine wanted a 17" clutch or we would have to change the flywheel as well. Big is better - so the hunt started for a 17" clutch.

We could source this size, but only as a single plate, and all our operating mechanism in the bell housing plus slave cylinder would have be replaced before we could cobble it together. So the new pipe I'd just had painstakingly made in Germany had to go as well as a tried and tested adjustable clutch mechanism. I was told the new one would be self adjusting, which worried me, and would take the torque I wanted to run through it, which also worried me, because I didn't know the power or torque or anything about this new engine, only that it should be bloody fast!!!

These technical boys with their books and part and chassis numbers - What would we do without them?!

We finished the Truck off half a day before we had to load up and go to Ireland.

So it was over to the airfield one and a half mile strip we went to do a bit of testing, but tried not to break anything as we wouldn't have time to mend it before we had to go! With Ben stood up in the passenger side of the cab, hanging onto the roll bar, I put my foot down to see how my new investment performed… Turbo boost pressure, engine oil pressure, and temperature, engine water temperatures, clutch operation, compressor air build-up speed, and governor cut-in time etc., etc. All seemed to be ok - but just ok - The new engine didn't seem to have any more power than the old one. It had been a while since I'd driven the Truck though, so I thought I must be wrong!!

All systems go - Let's get on a ferry and blow them away in Ireland………

We used Ireland for our proper testing, and although we went well, I wasn't convinced we had any more power than with the old engine, so I started to worry about what I'd bought….

No points in Ireland as this was not a Championship round.

Back at base in preparation for the next most demanding Meeting of the calendar, we'd had manufactured, a new set of adjustable shock absorbers by a guy who used to do the damping on a Super Race Truck. Which, if we actually adjusted did appear to create a difference when on the Track, during cornering. As this was the most important thing, it had to be done in a hurry, and in between sessions, as Ben had to take one end off the Truck to adjust, taking some half and hour each, on the ones we had been using. We were also going to experiment with some major, radical brake modifications to see if they would improve the braking. I don't mind telling you about it now, but at the time it was highly secret, with blankets ready to cover the brake drums up when removed at the Track. What we had decided to do was run a softer compound brake lining material that would wear out quicker. I.e. complete pad in 1 or 2 hours of Racing, instead of the type we were currently running, that went hard, with them glazing up quickly and going as hard as two hot metal surfaces being pushed together. They did go the distance, and when removed, were not more than half-worn. So they stood up to the heat and duration ok. What we were planning was a big risk, especially with the next part of the experiment, to see if the brakes could be improved. We wanted to groove the brake drums to take a small cut of the lining material each time the brake was applied, stopping the glaze effect and to maintain a bedded-in lining throughout a complete Race, and to direct the brake dust out of the drum.

As far as I was aware, this had not been tried before with Truck brake drums and shoes, and definitely not successfully in Truck Racing. So it was risky, and unproven, but Ben convinced me to try it…

We eventually found a machine shop that could hold the large Truck Brake Drum in place, and rotate it, as well, as the groove we had guessed needed to be on a 45-degree angle to the rotation of the wheel. So, offside needed to be opposite to near side, not to create imbalance, and 4mm wide and 2mm deep, leaving 8mm of the drum thickness untouched. This was worrying, as I have known the standard drums to explode under the heat and load imposed on them in Race conditions! I decided to use and experiment on new drums, costing a packet, for four front and four rear, including a spare for each corner of the Truck as they were all handed.

Anyway, the machinist turned green when I made my requests! As to get an accurate 2mm deep cut across a 10" curved surface, which also just happened to be circular, on a 45-degree angle was not at all easy to programme into the cutter. After three attempts he got it spot on!

On the way back to the yard with them all in the van, I was crying at the cost of the two failed experiments, and the machining! I kept asking Ben "Did he really think it would work?" He replied "We won't know until we've tried it, will we Dad!"

We fitted them to the Truck, but could not try them in Race conditions until we arrived at Zolder. (The most demanding circuit we visit on brakes!) What would the wear rate be? Would I tear the linings off the shoes? Would the drums shatter under heat and load? We will take 6 x sets of old, and new shoes as spares, and old drums, as well as new, in case our new idea didn't work. (Spares weighing around one ton in weight) to make sure we had enough on board in Belgium.