Failed certification

Dwight Southerland · 07-26-2025, 05:28 PM

Bounced at the 1975 Sports Nationals for 1.7 degrees too much duration. Measured by masking tape wrapped around the balancer. Yeah, right.

Bill Ringer · 07-26-2025, 07:06 PM

At Pomona LONG ago my teardown after Class elims the gasket-deck numbers were scrutinized. It was out of spec by .001" to .002" depending an where they measured the gasket. After some discussion between two DTD's it was accepted and my Class win confirmed. The measuring instruments they used had current calibration stickers and were +/- 0.001" accuracy. So it would be a stretch to reject something where the amount out of spec was a total of 0.002" between two measurements (deck & gasket). I did not have to bring that up, glad that it did not come to me having to point that out. Tech was thorough and accurate. 0.003" out of spec would be hard to challenge when the instrument error is no more than 0.001". At a Topeka teardown I saw the tech department pour another racer's exhaust port at least three times trying to give the him a chance to get it to pass by letting him repeatedly ice the cylinder head. They couldn't get it to measure in spec and ultimately were DQ'd with no complaints, grateful for the extra effort by the tech personnel.

Mike Pearson · Today, 01:19 PM

About 22-23 years ago I won class at the gators. My very first class win. I was torn down and the intake valve was found to be .001 undersize. I was tossed. There was no discussion on the accuracy of the measuring tool. The valve had many runs on it and it had tuliped causing it to measure small. It was definitely not a performance advantage. I had the heads rebuilt with new valves and presented them to tech for inspection before I could race at the next event. The new valves were almost a tenth quicker after the change. In hindsight I probably could have heated the valve to 1300 degrees and it might have measured big enough to pass. I was young and didnt think of that until much later. needless to say I was disappointed that I did not pass and get the class win or get to race in the eliminator.

07-26-2025, 05:28 PM	#1
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,001 Likes: 64 Liked 779 Times in 193 Posts	Re: Failed certification Bounced at the 1975 Sports Nationals for 1.7 degrees too much duration. Measured by masking tape wrapped around the balancer. Yeah, right. __________________

07-26-2025, 07:06 PM	#2
Bill Ringer Member Join Date: Sep 2007 Location: Colorado Posts: 108 Likes: 34 Liked 145 Times in 26 Posts	Re: Failed certification At Pomona LONG ago my teardown after Class elims the gasket-deck numbers were scrutinized. It was out of spec by .001" to .002" depending an where they measured the gasket. After some discussion between two DTD's it was accepted and my Class win confirmed. The measuring instruments they used had current calibration stickers and were +/- 0.001" accuracy. So it would be a stretch to reject something where the amount out of spec was a total of 0.002" between two measurements (deck & gasket). I did not have to bring that up, glad that it did not come to me having to point that out. Tech was thorough and accurate. 0.003" out of spec would be hard to challenge when the instrument error is no more than 0.001". At a Topeka teardown I saw the tech department pour another racer's exhaust port at least three times trying to give the him a chance to get it to pass by letting him repeatedly ice the cylinder head. They couldn't get it to measure in spec and ultimately were DQ'd with no complaints, grateful for the extra effort by the tech personnel.

Today, 01:19 PM	#3
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,447 Likes: 615 Liked 1,923 Times in 578 Posts	Re: Failed certification About 22-23 years ago I won class at the gators. My very first class win. I was torn down and the intake valve was found to be .001 undersize. I was tossed. There was no discussion on the accuracy of the measuring tool. The valve had many runs on it and it had tuliped causing it to measure small. It was definitely not a performance advantage. I had the heads rebuilt with new valves and presented them to tech for inspection before I could race at the next event. The new valves were almost a tenth quicker after the change. In hindsight I probably could have heated the valve to 1300 degrees and it might have measured big enough to pass. I was young and didnt think of that until much later. needless to say I was disappointed that I did not pass and get the class win or get to race in the eliminator. __________________ Mike Pearson 2485 SS