The engine fired right up and we had good oil flow as we could see the oil flowing between the spacers and off the rocker tips by looking through the filler cap hole on the rocker arms.

The first full pass showed us a problem. (Note: This is the first set with the .0015-.002” clearance) We drove the car around the pits and went through a couple heat cycles. Then we checked the lash and prepared for the first run. At about 600’ the engine felt flat and started to slow, I hit the kill switch and knew something was wrong. When we pulled the valve covers we pretty much stood there gawking at what we saw.

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Five pushrods were gone (fell down in the oil valley) and a couple rocker arms were still holding valves open even thought there was no pushrod under the rocker arm. We thought we had broken valves off but when we loosened the rocker shafts all the valves shut and the heads looked normal. I had no idea what had happened until we tried to move some of the rockers on the shaft. Six of them had seized to the shaft.

I couldn’t believe it and neither could Comp Cams when I called. We ran over everything I had done and it all sounded OK. They had me return the rocker arm kit and sent out another. Between when it got here and installing it we discussed what could have gone wrong. It became obvious there was not enough clearance between the rocker arms and the shafts for this radical of a cam. If Comp Cams made them loose enough for a .700” lift roller cam they would be so noisy on a street car you couldn’t hear anything else. When the next set arrived we had them honed out and that solved the problem.

It always seems it is the little things that create problems. I never even considered checking this clearance. If I would have I might have thought it was pretty tight for a race engine. Actually racing a car is a never-ending lesson in what will and what won’t work. I learned .002” clearance between steel rocker shafts and steel rocker arms is not enough for high-lift race cams and 7000 RPM. I hope I have saved you some of the problems I had and showed how easy it is to prevent it from happening.

Like I said earlier, this little adventure will make the installation easier and alleviate a nagging problem with the Pro-Magnum Mopar rockers when they are used in a full-race engine. There will be instructions in the 1321-16 Comp Cams kits from now on. The rocker arm kit and the pushrods we ordered are now a part of the “Back-2-Basics” combination and I feel the super strong rocker arms will serve us for seasons to come.

In closing I just want to thank everyone at Comp Cams who went the extra mile to help me find out just what caused the problem. I was afraid I would get an excuse or told I did something wrong. I am glad Comp Cams has always been our choice for camshafts and components in our Back-2 Basics Mopar engines. If you are looking for a custom grind camshaft or need to solve a problem with your current combination call their toll-free Cam Help line. They are there to get you back on track and will work with you just like they do the big-name pros that use Comp Cam products.

--Jok

Back 2 Basics  [5/5/05] The latest updates on our “common sense” bracket racer