Tech Talk #33 – Racing Through the Years with the All-Star Drag Racing Team

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

In the drama of drag racing, drivers are the stars and engine builders are the extras. I understand why the Best Actor at the Academy Awards gets his picture on the front page while the camera operator gets a mention in the final paragraph. After all, no one interviews the winning engine after a final round; it’s the drivers who get (and deserve) the glory.

But engine builders, crew chiefs, sponsors and chassis builders have one night in the limelight. For 35 years, the Car Craft All-Star Drag Racing Team has recognized the men and women who work behind the scenes. The stars and planets must have been aligned perfectly when this year’s winners were announced during the Mac Tools U.S. Nationals because Reher-Morrison Racing Engines won the All-Star Awards for both Pro Engine Builder and Sportsman Engine Builder. I was truly surprised and genuinely grateful to accept these awards on behalf of the 23 people who work at Reher-Morrison and the hundreds of customers who use our engines. To be chosen by the fans and racers who vote for the members of the All-Star Drag Racing Team was a highlight of our 30th anniversary celebration.

Looking at those two miniature Christmas Trees that are displayed in our shop’s break room stirs memories of years past. Buddy Morrison and I accepted five straight Pro Stock Engine Builder awards in 1982-86. Can it really have been 16 years ago? It’s difficult to comprehend all that’s happened professionally and personally since then. I only wish that Buddy and Lee Shepherd could have been with me on the stage again this year.

It’s a sign of the times that there are now two engine builder awards. There was no recognition for building sportsman engines back in the ’80s. Although sportsman motors have been the foundation of our business since Buddy and I built our first Chevy small-block in 1972, there was a line that divided sportsmen from the pros. Now, however, with the advent of fast brackets, Quick 16, Top Sportsman, Fastest Street Car and similar high-horsepower categories, the distinctions between Pro and sportsman motors are blurred. In fact, the technology and components in many of our Super Series sportsman engines would have been considered state-of-the-art in Pro Stock not long ago.

As I write this column on a Sunday afternoon, the wail of a big-block Chevy is reverberating through my office. Racing is a 24-7 job these days; if we’re not testing an engine on the dyno, racing it down a drag strip, or making new parts on the CNC machining center, then we’re thinking about and talking about what we’re going to try next. I used to think that technology in racing trickled down from the top classes to the weekend warriors – but now with the instant communication of the Internet and e-mail, information moves more like a flood than a trickle.

A case in point is short-block development. We are constantly working on improving cylinder sealing while reducing friction and parasitic losses. You might think that after 30 years, we’d have learned everything there was to know on the subject – and yet every season we discover how to get more power out of a given engine displacement.

The most important attribute of a short block is how well the cylinders are sealed. The rings, the ring grooves, and the honing procedure determine the quality of this seal.

It’s important to remember that the No. 1 source of friction in an engine is piston ring drag. In a typical big-block V8 engine, each of the 24 rings is dragged up and down the cylinder walls more than a mile every minute. The top ring only performs useful work in the first few inches of the power stroke; the rest of the time, it’s just soaking up power. The second and oil rings don’t contribute to power at all – they’re scraping oil at the cost of more friction. That’s why reducing ring tension can dramatically increase engine output.

Occasionally a customer will tell me that his engine smokes when it’s first started. I explain that that’s intentional. There can easily be a 30-horsepower difference between an off-the-shelf low-tension ring package and an optimized ring combination. If you install oil rings that pull 28 pounds of drag on a fish scale and full-width second rings, you can be assured that the engine is not going to smoke. However, it’s also not going to make as much power as a motor with handpicked low-tension oil rings and back-cut second rings.

We build our engines as close to the lower limit on ring tension as we can without stepping over the edge. A racing engine shouldn’t put out enough blue smoke to kill every mosquito in the county, but it should be very close to the line. We religiously check the ring tension in every short-block we build; it’s as critical as checking the bearing clearances. Unless you measure the ring drag in every cylinder, you can’t be certain that a box of rings wasn’t mislabeled or a set of expanders wasn’t too stiff.

Honing also plays a critical role in minimizing internal friction. You must balance the conflicting requirements of lubrication, ring seating and drag. If you were concerned only with minimizing friction, then a mirror-smooth finish would be ideal. Unfortunately, a slick surface will not provide adequate lubrication and it won’t produce an effective ring seal. As with many aspects of engine building, there is no perfect technique that satisfies every requirement. Years of experience, testing and racing teach you the best compromise.

We now have tools that simply weren’t available when Buddy and I opened our business in the back of an auto parts store. For example, we routinely check the hardness of every block before we begin the honing process. We know from experience what stones to use, how much pressure to apply and how many strokes to take on a block with a given hardness. Then we use a profilometer to measure the surface finish; it’s far more accurate than running a fingernail over the cross-hatch pattern like we did in the old days!

When you’re looking for maximum power, it’s important not to have too much oil circulating in the crankcase, especially with a wet-sump system. Like ring drag, windage is a parasitic loss that reduces the power that’s available to accelerate the car. A common mistake is to order the biggest, baddest oil pump in the catalog. We use a standard volume pump because we know from our flow tests that a standard pump provides adequate lubrication for our sportsman engines. That’s because we machine and assemble our cranks and rods with minimum side clearance and restrict the flow of oil to the top end. The clearance between the rods and crankshaft cheeks greatly affects the total oil flow, much like a metering jet. Wrist pin galling is usually the first sign of inadequate oil flow.

Learning about engines is a never-ending process. Drag racing has occupied my thoughts for more than 30 years, and I’ll probably be thinking about cams and cylinder heads when I draw my final breath. That’s why it’s an honor to represent the gearheads, mechanics and engine builders who have made NHRA drag racing the world’s fastest motorsport on the Car Craft All-Star Drag Racing Team.