Fear and Loathing on the Vintage Racing Trail: At the Crossroads
By Brion Gluck
It was a backwoods Georgia town less than an hour from my house, but it was late at night, the rain was coming down in sheets, and I was at a crossroads neither Mr. Rand nor Mr. McNally had seen fit to mark on the map. Which way to go? I didn’t know.
Bone-tired and with the teeth nearly rattled out of my head by over 800 miles in my ancient Bronco tow vehicle, I had been on the road nearly 20 hours straight driving to Florida to pick up yet another motor for the Team Dark Horse 1971 Mach I. This is the distinctly unglamorous part of amateur racing, the endless hours getting the car ready for a race weekend.
It was also an apt metaphor for my predicament with the car and the racing season. Which way to go? What to do? Choose one road, and you end up safe at home in bed in an hour. Choose the other, and you could end up squealing like a pig while someone plays a banjo. Metaphorically, at least. Racing is a series of choices and trade-offs, and some of them you have to make in the dark and without a map.
I wasn’t expecting to be finding myself at a crossroads in late June. Last spring, the original road-race engine for the Mach I had finally given in. And over the fall and winter, Coast High Performance had built up the “Mill of Steel,” a 347 small block stroker, as its replacement.
During the long downtime, we’d made a lot of other changes to the car while waiting for the new motor to be built. Notably, the Mach I had gone on a diet, losing a lot of now-unneeded and heavy stock components. The dash was now aluminum, the fuel pumps electric, and the windshield Lexan.
The heavy old Z-bar was replaced with a set of Wilwood lightweight pedals and a composite master cylinder, and the cable clutch converted to hydraulic using a McLeod hydraulic throwout bearing. A new Tremec 5-speed road racing transmission was not only lighter but gave us better-spaced gearing for road courses.
Even the alternator went to Jenny Craig. An East Coast Auto Electric high-output single-wire racing alternator simplified the electrical system considerably while saving a whopping 10 pounds over the stock unit. Billet aluminum pulleys from March helped get the driven speed of the alternator down to something reasonable for the high RPMs the engine would be living at on the track.
John’s Mustangs supplied new CNC brake master cylinders, and Stewart Components provided a new high-flow water pump. All in all, the car was much improved. What we needed now was the motor to go with it.
Less than a week before the late April Historic Sportscar Racing vintage race at Road Atlanta, the Walter Mitty Challenge, the new engine finally arrived in a crate from CHP. Why so late? Delivery delays for the heads had pushed us right to the limit for being able to make the race.
Once out of the crate and onto the test stand, I was able to get my first look at the motor in the flesh. The first thing that would need to be changed, I thought, was the oil pan. CHP had sent the new engine out with a 7-quart pan with no baffles to keep the oil near the pickup while cornering. A quick call to Canton and a 9-quart road-race pan and windage tray was on its way overnight to the workshop. The Canton pan was beautifully made, with an innovative trap-door design that keeps the oil in the bottom no matter how many lateral Gs you’re pulling.
Of more concern was what I saw with the pan off. CHP had left out a stud girdle, which ties the main journals together. I think a stud girdle is critical for a two-bolt main block, particularly a late model unit which has less metal than older ones do. George Klass at CHP thought we could run without it for a race, although we decided to lower the rev-limiter from 7500 RPM to 7000 and put a 6000 RPM pill in the shift light to be on the safe side.
I could also see that the block was missing a number of plugs for blocking unused oil and water passages, and the numbers on the harmonic balancer were reversed for the 1971 Mach I. Easy details to fix, but a definite reminder to pay attention to the little things before you bolt a new engine in. Not as easy to fix before the race was what looked like a poor job of port-matching on the intake. That would just have to wait until later.
On the test stand during an hour or so of break in, the motor sounded good, with a nice throaty exhaust note. The sound wasn’t as crisp with the new 10.5:1 compression as I’d remembered from the previous 13:1 engine, but running was the main thing at this point!
The race weekend at Road Atlanta saw beautiful, sunny spring weather and there was a huge turnout of cars and fans. My race group had 68 cars, and the class 20 or so. Craig Ross was there with his yellow 1970 Boss, as was Juan Gonzalez with his unbelievably fast 429 Boss.
“They made me run the small carb, so I’m only making about 700 horse,” he said, before going out and taking third overall in the group 6 endurance race on Saturday.
Pete Rogal’s Wimbledon White 1965 Shelby GT350 also ran well, upholding it’s heritage as a former Canadian national champion car.
The Mach I felt really tight during Thursday practice, with the nose much lighter and the car feeling very balanced. Even though down on horsepower from my old engine, the new one was making much more torque and with the closer gearing from the Tremec box, the car was rocketing out of corners and pulling hard on the straights.
Even driving slowly and conservatively in the first practice session, we started out running times in the 1:52 range, which were some of my best ever at Road Atlanta. And I knew I wasn’t even beginning to explore the car’s limits.
Back in the pits between sessions, we checked out the car while Barry Grant tech rep Scott Witmer tuned the Demon 750CFM road race carburetor for more throttle response. Everything was almost perfect, but I had noticed the oil pressure begin to fluctuate a little, bouncing 15 psi up and down.
In the second practice session, I began to push the car harder and feel more confident that all the new bolts and welds were going to hold. The lap times dropped into the 1:40s and I really enjoyed being able to pull the Porsches and Corvettes on the long straights.
But the fluctuation in the oil pressure was now pronounced and growing, and I reluctantly headed to the pits. A quick call to CHP, and we concluded that one or more rod bearings was probably going away. Mike Broadway of Cold Blue Steel Racing pitched in to help as we dropped the oil pan and replaced all the bearings with fresh off-the-shelf parts from a local auto parts store.
Sure enough, the No. 3 bearing hadn’t quite spun but had had the crush knocked out of it. By 2 a.m., with the help of a generator, halogen droplights and a portable compressor for the air tools, we had the car back together and ready for qualifying.
After Friday morning’s practice, we switched to EBC Yellow Stuff Kevlar brake pads and went out for the afternoon qualifying race. The car was running very well, turning consistent laps in the low 1:40s, and we qualified 6th in class for the sprint and endurance races. It looked like a full race weekend was in the works, and that made what happened next so unexpected.
On the hot lap for the endurance race on Saturday, just cruising at 3000 RPM coming out of Turn 7 on the way back around for the start, the new CHP motor popped like a small grenade going off. That was followed by the sound of block and oil pan parts hitting the ground, and then a spooky silence. This can’t be, I thought, not again. Not two races in a row.
I pulled over to the side of the track and got to watch the rest of the race from the wall. It was obviously a catastrophic failure; I could see the harmonic balance hanging down and the front timing cover shattered with the timing chain hanging out. Once the pan was off, I could also see that the steel crankshaft had broken in half right at a counterweight. What had happened was obvious. Why was still a mystery.
Back at home, I sent the rotating assembly off to Mike Broadway for a post-mortem. Mike believes that the distributor hold-down came loose during the hot lap, letting the distributor turn and adding a massive amount of timing advance. The advance caused detonation, and the detonation stressed the crank enough to cause it to snap. As is so often the case, it’s the little things that get you, but a blown motor is an expensive way to be reminded of it.
Was there an inherent flaw in the crankshaft? Would a stud girdle have made a difference? Who knows. The real lesson for me was that a reliable motor for road racing needs to be specifically built for that by an engine shop with experience in it, since the requirements of drag and road racing are so different.
Panhandle Performance in Panama City, Florida will be building the new engine for the Mach I. Mark Biddle is someone who understands the needs of road racers, and being only a few hours from my home base in southern Georgia should make the inevitable 11th-hour scrambles to get the car ready for a race much less stressful.
The new motor will be a little shorter stroke, at 331, to give us a little more RPM margin at the top and provide reduced stress on the rods and crank over the CHP 347. The in-house dyno and flow benches at Panhandle should let us tune the motor for a genuine and bulletproof 500-550 horsepower. Needless to say, I don’t want to be building a new motor again for a while if I can help it, so durability is high on my list of goals. That means using nothing but race-quality components in both the top and bottom end this time.
Crank and rods from Scat will be teamed with Ross pistons and the same excellent Comp Cams camshaft and valve gear used on the last motor, with Federal-Mogul, Ferrea competition valves. Canfield heads up top, a Barry Grant Demon carb, MSD distributor and ignition, Hooker headers and a BHJ harmonic balancer will also be part of the mix. Fittings from Earl’s will hook everything up. An oil cooler and radiator from Fluidyne will keep things cooled off. Fel-Pro gaskets and ARP head studs are also on the spec sheet.
Panhandle should have the new motor ready for a September race back at Road Atlanta, but until then the Mach I will be running the second CHP 347 intended for Jack Flinn’s 1968 Mustang endurance racer. It’s all but identical to the engine that blew, but if we can avoid detonation this time it should be as competitive as that one was.
If not, the Shelby’s and the high bank at Charlotte Motor Speedway may be treated to another Team Dark Horse blown motor DNF in July. Here’s hoping we took the right road to changing our luck.