Betty and Gene
Bill: Okay Betty and Gene, let's go to the Datsun now. How did this come about?
Betty & Gene: Well, as noted, the Stude had gotten to the limits of its safe speed and we wanted to go to the next level. We liked the competition coupe kind of car but these do have a history of blowing over at Bonneville at the very high speeds and of course we didn't want anything like that.
There was an interest in building a real ground up race car to safely go after higher speeds and the rule book had been updated to allow just that.
We started to look around our local junkyards for a Plymouth Arrow at first, this would have been suitable, and we wanted to stay with an American car. But the Arrow was not plentiful, and the junkyards wanted a lot for the body if they got one in good condition. Competition Coupe rules had been opened to allow foreign bodies by this time.
In the Fall of 1980 we were offered a 1975 Datsun B210 which was a tiny coupe with maybe a 100-inch wheelbase, with a flawless body for only $40 so we decided to take it. Tom was immersed in his college engineering courses at this point and he took on the design work for it and made very rapid progress. On New Years Day '81 we were putting chalk lines on the garage floor to lay the chassis out. This one was entirely scratch-built and we had it out to Speed Week that same year in primer.
Bill: The photos Tom sent me show a gorgeous car and the front of it designed for downforce. He told me that the belly pan is designed to be an inverted wing form, with side skirts to prevent the air escaping out the sides, and there is around a total of 3000 pounds downforce on the car at 300 mph. This gave it such safe handling and steering, he said, that you could put orange cones out on the Speed Week Long Course at the end eight feet apart, and he would guarantee he could put the five-foot wide car between them at 300 mph! Now that's impressive!
B&G: Once Tom got into the design picture it was the end of trial and error. If you want safety with your speed, you have to start with scientific design. A very great deal is known nowadays about aerodynamics and you've got to do your research when you think about cars over 200 mph. Or you're courting disaster!
Bill: What wheelbase and suspension did the Datsun have?
B&G: It was stretched to 195 inches and we made a front beam axle from 2" x 1/4" wall chromoly tubing with a big drop. It used trailer leaf springs front and rear, four of them altogether, with axle-mounted rack and pinion steering from a center point so there was no bump steer.
The rear axle was like the Studebaker's, homemade with big axles, but this one had a Halibrand Champ Quickchange added to it. We ended up with a 1.94 ratio in high gear with the Datsun. There were four wheel disc brakes from Ford pickups, so there was plenty of braking power. And we had two big parachutes for it in the practice of the day for that class of car.
Bill: Okay, for this type of car a suspension is considered best.
B&G: Yes, but there's a subtle point here. With so much downforce in the car, the suspension only operated up to 180 mph, which helped acceleration over any bumps on the course, but over 180 the axles were bottomed on their rubber bumpers and from there on up, it was the same as solid.
Bill: I see. Very impressive! How about the power unit in this one?
B&G: We wanted to start off with the Datsun in the smaller engine classes, but set everything up to go with bigger engines later. So we started with a 354 Chrysler set up to run on four cylinders with two firing on each side. We could have done the same thing by using just one bank of the 354, and others have done that. But the way we did it, you could set your heads up with all the valves in place, just not actuated on the dead cylinders by deleting the pushrods and lifters, and if you burned a valve you could swap another head for the other side and get the engine back in action quickly.
By this time we had one of those old Potvin front-mounted 6-71 blower setups to use which we got from Fred Dannenfelzer. It had originally belonged to Fred Larsen of Mooneyes fame. This was good for a low hood. The drive at one time had even incorporated some change gears so Larsen could change ratios, but by the time we got it there was just direct drive. The 6-71 had a Hilborn two-port injector on the intake side.
Bill: I always wondered how those worked with those very long large bore pipes running back and up to the intake ports carrying heavy fuel vapor and probably some unvaporized fuel spray. Thinking about fuel distribution to the cylinders, I mean.
B&G: It seemed to work fine. We used only straight methanol with it.
Bill: How did you deal with the missing conrods and pistons and the balance of the crankshaft?
B&G: Two conrod caps with their normal bearing shells were used to replace the missing rods and keep the oil pressure in the crank. Tom did some calculations to deal with the crank balance factors, but in practice the engine was smooth at only one rpm range, and a bit rough at others. But workable.
Bill: What about the gearbox and clutch?
B&G: On this one we used an iron Chrysler four-speed with a set of Liberty gears made for drag-racing. They had big straight-cut gears and big chunky dogs with plenty of backlash. Like a motorcycle gearbox except that, of course, the input shaft ran at crank speed. It was designed to be used with a Hurst shifter and to be shifted clutchless once you got to the top of first gear. To shift you just lifted momentarily and pulled the shifter and it would change gear perfectly with no damage to the parts. We had a two-disc Long-style clutch in the car which would not be inclined to release very quickly at high rpm, so it was best to go with the clutchless shifting.
With this car, Tom took over the driving duties and Gene became crew chief. But from '86 to '89 Betty drove the car at times, doing maybe a dozen or so passes up to 240 mph. On one of them the blower exploded and that was the end of the Potvin front drive system. After that we changed to a conventional top-mounted blower and had to make a big bump on top of the hood.
Bill: Betty, why did you decide to get into that?
Betty: At the time, Tanis Hammond and I were the only women out at Bonneville who would drive, and I felt some obligation to show the guys that women could do this just like they could. And Bill, it was MY TURN! I always had a theory that the car didn't know if its driver was a man or a woman. Years later I got back into it with George Fields' car, and in '03 I set a class record in comp coupe at 263 mph and got myself into the 200 MPH Club. I'll tell you about that later.
The very first pass we made with the car at Speed Week in '81 was only 97 mph, to just feel things out and make sure everything was working. Naturally you want to do that with a new car.
Bill: What was next?
B&G: The next big thing was when we got a chance to buy out Louie Labash's Donovans. At a point in the mid '80s, Louie offered them to us as a package for $15,000, which was a steal for two complete engines and enough parts to make two more. We had to go get a loan to pay him for them. The reason he parted with them was that Les Leggitt was building and tuning his engines, and Les preferred working with Keith Black Hemis.
You see, we were already thinking about our streamliner, and by '85 Tom was doing some preliminary design. We decided we would use two Donovans in the streamliner, coupled up, and four-wheel drive. And we would put one in our Datsun and run it so we could learn about it and work out the cooling system details, dry sump oiling system, blower drives and fuel injection arrangements we had in mind.
The first Donovan we built up for the Datsun was a 300 incher with four inch bore and three inch stroke. We ran that one on 30% nitro and it was very, very fast.
One of the early iron Chrysler engines was in the Datsun when Tom took his 293 mph class record, the one which still stands today, and he got himself into the 200 MPH Club. The later Donovan operations were essential to making the engines reliable and getting the tune up details dialed in for the streamliner. The complexity of a twin engine four wheel drive car makes the engine issues very difficult to manage, so having them in the proven Datsun comp coupe chassis was vital to rapid development progress.
Bill: Terrific! I looked up the 417 Donovan on the Internet and there are some good articles about it. What features attracted you to it?
B&G: It was ideal for our purposes from several standpoints. Donovan came out with it in the late 1960s as a derivative of the '57-8 392 Chrysler which as everybody knows, was a highly successful hot rod racing engine and made itself a legend still potent today. The 417 cubic inches of the Donovan merely represented a 1/8" bore increase compared with the 392. But it was very different than the 392 in many ways.
Ed Donovan had a lot of previous experience with serious racing equipment as a professional Offenhauser mechanic and knew the weaknesses of the 392, so he designed his 417 to be much better. It had an aluminum block with thick, wet, removable iron cylinders (available in various bore sizes) sealed at their tops and bottoms into the block casting. Instead of having ordinary cylinder head bolts or studs at the decks, which tend to create local distortion, he used long studs to clamp the heads on which went all the way down to the massive structure in the block surrounding the main bearings.
His block was water cooled, with intake fittings at each cylinder point on the block. This meant a lot of hoses and plumbing, but each cylinder got equal cooling compared with the usual practice of putting the water into one end of the block.
His design incorporated a "dry deck" where no water transferred through the head gasket from the block to the head as in normal production engines.. This avoided the possibility of water leaks at the head gasket, which has bedeviled engines with removable heads under racing conditions for a hundred years, due to the pressures and stresses at the head joint. The legendary Offenhausers and Millers, to overcome this, did not have removable heads. Instead, the cylinder blocks and heads were made in one piece, and this assembly bolted to the separate crankcase.
Donovan gave his 417 a stout main bearing arrangement, much stronger than the 392, with a massive single-piece aluminum girdle forming the main bearing caps in one align-bored piece with 72 big studs securing it and dowels to hold alignment. His idea was that all the production and racing aftermarket cranks, cams and so forth used on the 392s would be interchangeable into his 417 as a practical racer's feature. There were loads of 392 racing equipment around at the time.
At first Donovan did not make his own aluminum heads for the 417, and people used iron 392 heads on the 417 blocks. But after a time, he did get his own aluminum heads out into the market for his blocks. These have, in turn, their own water inlet and outlet fittings with more plumbing.
Bill: Very interesting. What happened to the Donovan company later?
Gene: Ed Donovan passed away some years ago and I don't think he ever made a fortune, unlike some other names in the hot rod parts industry. But he DID make an awful lot of good racing equipment and it's still out there today. I think we're in touch with just about all the Donovan people in the country, it's a big network, and if we needed anything, we could get it easily. And, the Donovan company is still in business in other hands now, manufacturing a lot of quality Chevy racing blocks and so forth. They will still supply some 417 pieces as well.
You realize, obviously, the drag-racing world went to solid aluminum blocks a long time ago. But for our application at Bonneville, we have to have water-cooled blocks and heads to run for miles under power.
Bill: What kind of gasket is used at the head joint of a Donovan?
Gene: None at all, just a .031" copper wire o-ring laid in a .020" deep groove around each cylinder, and you assemble the parts. Leakage is never a problem, and if any minute seepage did occur, it wouldn't matter.
Bill: I gather the 392 valves, rockers, shafts and stands are interchangeable?
Gene: Right, but people sometimes use aftermarket parts for these. We are using the 392s and it means adjustable pushrods which are a little hard to deal with for tappet adjustment. The Donovan magnesium valve covers are 1/2" higher than the 392 to give more room for high lift cams, but the heads use the same steel tubes - just longer- for the spark plugs, which are about .060" thick and form gaskets for the plugs same as the 392. This keeps oil away from the base of the plugs. But this means you have to remove the plugs to remove the covers because the tubes help hold the covers down with seals at the top like the 392. This in turn means a little more time to get the covers off for tappet inspection on a turnaround for an FIA record. But we love our Donovans just the same!
Bill: I can understand that! Okay, we're beginning to get into the fabulous streamliner part of the story but next, let's took a look at the famous 600 mph Burklands tire spinner! That's a fascinating piece of homebuilt hot rod equipment.
Copyright © 2009 Bill Hoddinott