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#1 |
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Well, my first teardown didnt go as expected. We were chosen to go to the barn Friday after class. After removing the head for Wayne (D5) and crew to inspect, the following numbers were found,
Intake runners, 137.x on a 140cc max Exhaust runner, 57.x on a 60cc max Combustion chamber, 55.x on a 54.9 min Bore 3.935, stroke 3.005 .040 total deck, piston to head Also, bore, stroke, ring height, carb, intake, wheelbase, etc all checked good. Valves were pulled and valve job and valves inspected, all also good. Then came the camshaft. Intake checked .396 on a .399 max. The exhaust checked .405 on a .399 We rolled and checked it a couple of times, with a range of .402 to .406 I couldnt believe it. I do my own assembly and knew exactly what I had, or so I thought. Travis knew where I went wrong and told me what to check when I got home. He was right, my checking lifter is a Comp Cams solid and the plunger is well short of the height of the hydraulic Smith lifter that's in the engine, right around .100 shorter. A rookie engine assembling mistake on my part, and I take full responsiblity for my ignorance. This resulted in my DQ. First off, I want to apologize to my son and wife for embarrasing them. I feel I let them down and I'm sorry. 2nd, I want to apologize to Tom Moock for our class runoff in Belle Rose, I am sorry for that as I hadnt changed anything since then, so it was undoubtedly wrong then also. And, I want to thank the Tech guys for showing me respect. They were very professional and went far above showing extra patience with me, because of it being my first time. Hell, I filled out the whole teardown card not knowing most of the area was for Wayne to put his notes in. (I was just trying to help.......) I'll see you guys at Indy with it apart for Tech to check and hopefully put this mess behind me. Wade Owens, 3913 Stock |
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#2 |
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Wade,
Dont beat yuorself up too bad. It was an honest mistake and we all make them on occasion. If you really wanted to cheat there are plenty other things you could have done. I don't know you but I do think you are a stand up guy for admitting your mistake and offering appoligies for something you really didnt know about. I would definately call your cam guy though as he should have followed your specs to begin with. Good luck with putting her back together and trust me it will be ok. See you soon at the races. |
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#3 |
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Wade, Sorry to hear about your DQ. The rule book says they should have checked it with a solid checking lifter with zero lash at the retainer. I'm trying to understand how different lifters will change the actual cam lift.
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4878 SS/GA 66CHEVY II Last edited by Darrin Christen; 05-01-2010 at 10:34 PM. |
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#4 |
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Different plunger heights will change the lift with a ball / stud type rocker arm (GM products for example). It won't with a fixed rocker like a mopar shaft.
Wade, the reverse is true for tech. If you have a plunger height of "X", make sure tech is the same height in relationship to the distance from the base of the lifter to where the pushrod seats, i.e., you have to know the lifter length, not just how low the pushrod cup is in relationship to the top of the lifter. Like Floyd said, it's nothing to beat yourself up on. I would be more embarrassed if you were leaving a lot on the table with sloppy specs. The numbers you gave show you are pushing up to tolerable limits. Good, that's what makes it, not sloppiness!
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Jeff Lee 7494 D/S '70 AMX |
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wade, ur not the first and wont be the last. but u did the right thing in accepting techs decision and u`ll gain respect from divisions
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David Crouchet |
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Jeff, so am I thinking right by saying that the taller lifter is actually slightly changing the rocker arm ratio due to the fact that the push rod would mover ever so slightly closer to the fulcrum of the rocker arm, which would increase lift?
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4878 SS/GA 66CHEVY II |
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Darrin,
You are on to something, but it's not that simple. At the rocker arm you are dealing with 3 angles. The angle of the pushrod to the lifter. The angle of the stud and the angle of the valve stem. If you extend these angles up they will meet at some point. The trick is to get the rocker in the correct position to get the desired ratio. The rocker ratio can be altered by moving the position of the rocker up and down these angles. When you do a geometry set up you have to stick with all the components or at least their sizes/shapes. Shorten the lifter or pushrod and the back of the rocker drops. That pulls it down the angle of the stud and can roll the rounded pad of the rocker back on the valve tip. Geometry changes. Wade, don't feel bad. My worst DQ was a blessing. Right side wheelbase came up short by 1/4 inch. Lost #1 position and record...Turns out there were problems with the right front suspension. The DQ forced us to look at things. Caught it before it broke and created real problems. I will bet you will find some othere areas of your engine to improve while you have it apart fixing the geometry problems.
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Adger Smith (Former SS) Last edited by Adger Smith; 05-01-2010 at 11:57 PM. Reason: sp |
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Wade, Don`t worry about class at Bell Rose, We change things on my car over the winter slowed it up 2 tens, changed back and picked up 2 tens in air not as good as Bell Rose. You are not the first to fall victim to Wayne`s tool for checking push rod and lifter length, Darrin Christen they use a adjustable solid lifter and your push rod, they make it the exact same length as your lifter and push rod you run in your motor to check valve lift. Tom
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Tom Moock 5704 STK |
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Thanks Adger, thats exactly the way I was thinking about it. I just didn't know how to explain it.
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4878 SS/GA 66CHEVY II |
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#10 |
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Tom, so if you run a hydraulic lifter, do they adjust the checking lifter to match your lifter collapsed or pumped up?
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4878 SS/GA 66CHEVY II |
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