ESPN's Tim Brewer answers your questions
Former championship crew chief and current ESPN analyst Tim Brewer answers questions from ESPN.com NASCAR Icons readers.
We know NASCAR fans have a lot of questions from watching Sprint Cup races, so we went to one of our experts for some answers.
Rocky Mount, N.C. Brewer: When the driver coasts into the pits he's got the car out of gear. What the driver's doing is basically trying to get a cool drink of water. But when the right side of the car comes down he actually reaches over, pushes the clutch in and puts the car in first gear. And that's when the tire jumps forward. In the process of doing that, the right rear tire jumps forward and hopefully the right rear tire changer has all the nuts tight at that point because if he doesn't it kind of messes up his rhythm a little bit. Could the tire issue at Indy -- wearing down the right rear -- be from the teams twisting the cars to have that sideways look?
New Orleans Brewer: Mike is exactly correct. When you've got camber in the wheel [meaning from top to bottom and you've got negative camber in the wheel] you're loading the tire to where it actually has the benefit of the corner utilizing all the rubber on the tire [meaning keeping the tire from rolling under]. But with the tire being toed out it also creates drag and friction on the right rear tire. And any time you create more drag and friction on that right rear tire you induce more wear. Andy Petree mentioned [during the ESPN broadcast] "turning the engine backwards" after Kevin Harvick's spin at Pocono. How does that happen and what does it do to the engine?
Naylor, Ga. Brewer: Kevin Harvick deserves a lot of credit there because when you drive off in that corner and you're anticipating "well, I've got to get back in the gas." And all of a sudden something hits you from the rear and you turn the car sideways, he stood it back in the gas just as hard as he could and really tried to dirt track the car and keep the momentum and save the car. But at the same time he was having those wheels spin forward. That's all a good thing because when the car started to go around the other way, Kevin had to get the car either out of gear or the clutch in because the first thing that happens when you go backwards, you turn the engine backwards, the oil pressure stops. And when that belt stops turning, and turning the other way, it can actually kick the oil pump belt off. It can spin the engine backwards where you have no oil pressure. It can also create a lot of damage because even the lifters in the engine in the camshaft are designed on a ramp so that they're going up and spinning the lifters. And when that engine starts going backwards they actually chatter on the camshaft. It creates devastation for the engine. But Kevin Harvick did a great job because he tried to save it as much as he could and when he found out, "hey, this is a lost cause," he had to spin the car the other way. But he did a great job because he finished fourth in the event. It tells me he had no engine damage. But all of this is happening in a matter of seconds. You just think, that engine's all of a sudden turning 9,000 rpms one way and the next thing if the guy doesn't implement proper procedures everything goes away and the thing is actually turning rpm backwards. But the oil pump getting kicked off and the oil pressure is the biggest related problems.
I have heard it mentioned on several NASCAR broadcasts that the dry sump pump pulls a vacuum in the crankcase to help the engine make more horsepower. How does this help?
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