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Color me Gone
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Excellent Jan, thanks for posting this.
 

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Premium Member
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Is Schrick the OEM supplier of V-Rod cams? Wouldn't surprise me considering Harley is using most of Prosche's OEM suppliers for this engine. Does anyone know?
 

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SUPERCHARGER GUY
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433 Posts
This is great info but what is important to remember this is general stuff. Make sure specific clearances are adhered to for specific cams as it says in the last sentance. The valves are not at their closest to the piston at tdc on overlap but just before and after tdc depending on which valve. Always start measuring from 15 deg before to 15 deg after tdc. Measure the clearance by fitting a dial guage to the bucket, push the bucket down until you feel the valve touch the piston and check the guage distance. Turn the crank a couple of degrees, check the clearance again continue this from 15 before to 15 atdc on both valves. you will see where the valves are closest to the piston. My minimum clearances for this engine are 1.2 mm for the inlet and 1.8 for the exhaust. Make sure when you set the dial guage above the bucket you get it as close to 90 deg to the bucket as possible otherwise you are not measuring a true valve to piston clearance.
If you are fitting oversize valves then also check the periferal clearance to the piston valve pocket. The piston rocks as it goes over tdc and the exhaust valve rim can scrape the edge of he valve relief. If the clearance around the top of the piston to the bore is say 0.030 inch this means the pocket diameter has to be at least (0.030 + 0.020)2 + valve diameter to be safe. I have seen to often a valve failure because the piston is tapping the valve edge on every rev and causing fatique.
Hope you understand me.
 

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HORSEPOWER said:
This is great info but what is important to remember this is general stuff. Make sure specific clearances are adhered to for specific cams as it says in the last sentance. The valves are not at their closest to the piston at tdc on overlap but just before and after tdc depending on which valve. Always start measuring from 15 deg before to 15 deg after tdc. Measure the clearance by fitting a dial guage to the bucket, push the bucket down until you feel the valve touch the piston and check the guage distance. Turn the crank a couple of degrees, check the clearance again continue this from 15 before to 15 atdc on both valves. you will see where the valves are closest to the piston. My minimum clearances for this engine are 1.2 mm for the inlet and 1.8 for the exhaust. Make sure when you set the dial guage above the bucket you get it as close to 90 deg to the bucket as possible otherwise you are not measuring a true valve to piston clearance.
If you are fitting oversize valves then also check the periferal clearance to the piston valve pocket. The piston rocks as it goes over tdc and the exhaust valve rim can scrape the edge of he valve relief. If the clearance around the top of the piston to the bore is say 0.030 inch this means the pocket diameter has to be at least (0.030 + 0.020)2 + valve diameter to be safe. I have seen to often a valve failure because the piston is tapping the valve edge on every rev and causing fatique.
Hope you understand me.
exactly. i was suprised when they showed checking valve to piston at tdc. the closest point is around 15 to 17 degrees . it can be slightly different according to rod ratio and how fast the opening and closing ramps of the cams are. the above method of checking valve to piston clearance is my favorite too.far more accurate than clay.
 
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