Valve spring destruction
Roy Johnson, engine builder for son Allen Johnson’s NHRA Full Throttle Drag Racing Series Pro Stock Dodge Stratus, lives to demolish the valve springs provided by Performance Springs, Inc. (PSI). “Valve springs are an ongoing problem for us. If I get a good spring, I can always find a way to tear it up by increasing the engine’s rpm and changing the cam lift velocity. The advances in materials and the heat treat processes that PSI has developed help but they can hardly keep up with us. By the time they learn something, we find another way to destroy the spring,” Johnson said with a chuckle.
Every month or so, Johnson gets new springs to try; often the updates come quicker. There might be two or three varieties and maybe, once in a while, he might find one that works for his high revving 500-cubic-inch mill. “First we’ll test them on the Spintron and if that doesn’t tear it up, we’ll put the spring in one of our dyno engines,” Johnson explained.
Johnson always uses a down-on-horsepower engine on the dyno to test a newer specification valve spring and, if it works to his satisfaction, Johnson will place the spring in a newer motor. If the updated spring tests successfully on the newer mill, it will then go to the track for further testing. If a new-spec valve spring lives through further torture, it might get fitted to a race engine for the first qualifying session – of four – during the Full Throttle Drag Racing Series race weekend.
“Every day that we work on the dyno we are looking to develop a different size wire and a different diameter spring, trying to get it to live, but most of the time the camshaft beats the heck out of it!”
Steve Bown of PSI Springs confirmed that Johnson “either breaks them or wears the springs out pretty quickly,” he said. “Our new Triple drag racing spring seems to be working for Roy and (some of) his competitors pretty well right now, but we continue to research and upgrade our products to help these guys.”
During the Bristol weekend in mid-May, another Pro Stock team was trying PSI’s latest spring configuration, the DR1263RML and was happy with it following an initial run. This triple spring, along with a couple of dual spring options are available to the Pro Stock community.
“Most significantly,” Bown told me, “We will soon be introducing a new line of springs for drag racing that we have developed. These utilize a new manufacturing process – signified by an ‘R’ following the part number – that improves the strength of the material, thus improving the life of the springs dramatically.”
Written by Anne Proffit.