Should I worry about Piston to Valve clearance?
02-19-2009, 10:18 AM
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Should I worry about Piston to Valve clearance? I am seriously thinking about upgrading from my cc503 cam to say something a little larger, maybe a cc306. I am just a little concerned about my valve clearance. I know that on untouched stock heads, i wouldn't have to worry. Unfortunately, mine aren't untouched. My heads were milled and I'm not sure how much. All I know is that the heads were milled enough so that when installed with a felpro gasket, my correct pushrod length is down to 7.000" instead of the stock 7.200". is there a way to calculate my piston to valve clearance without ripping off my heads? I am using 1.6 RR's btw
02-19-2009, 10:32 AM
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I didn't know you could mill heads to need a pushrod that short. I had my heads milled .040 and came up with a 50cc chamber. I don't think you can go much lower than that. In addition my block was decked .025 so I figured up I'll need about a 7.15 inch pushrod. Are you sure that length is correct? Another thing that goes into play is the thickness gasket you are using.
02-19-2009, 10:51 AM
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I thought tht was a little short, but in order to get the corret wear pattern on my valves, I needed to lower the pr length to 7. could there be other factors in play? The springs are installed at 1.8" nom and i am using CAT brand RR's. maybe the design of the rr's could be causing it?
02-19-2009, 11:01 AM
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to get the PR length I made a solid lifter, used a comp PR length checker tool, and adjusted the rocker to zero lash. I turned the motor over a couple times. then took off the rocker and looked at the wear pattern. I then adjusted the tool until the wear pattern was in the center of the valvestem. this is the correct method right?
02-19-2009, 11:23 AM
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to get the PR length I made a solid lifter, used a comp PR length checker tool, and adjusted the rocker to zero lash. I turned the motor over a couple times. then took off the rocker and looked at the wear pattern. I then adjusted the tool until the wear pattern was in the center of the valvestem. this is the correct method right?
02-19-2009, 12:13 PM
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I honestly don't know, that could be the issue.
I have the part number on some paperwork at home, I will check the part number later and get back to you
I have the part number on some paperwork at home, I will check the part number later and get back to you
