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| cam wheel mod | |
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| Tweet Topic Started: May 7 2012, 12:48 AM (1,710 Views) | |
| socal geo garage | May 7 2012, 12:48 AM Post #1 |
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Could a cam wheel be advanced by removing the cam pin and filing a mm from it >lining everything up and turning wheel clockwise ? is this the direction it turns? i did this today and turned about 1/4 of a tooth is clockwise the correct direction? has anyone else here ever tried same? |
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| Murf 59 | May 7 2012, 12:51 AM Post #2 |
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Our friend at 3Tech does this. But he uses a degree wheel so it comes out at 10degrees advance. They work great. |
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| Woodie | May 7 2012, 06:29 AM Post #3 |
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Going to be VERY hard to keep it in place. The pin is what holds it in place against some severe rocking moments. |
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| 944door | May 7 2012, 06:34 AM Post #4 |
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automatically adjusting between -5 and 5+ degrees all by itself lol |
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| socal geo garage | May 8 2012, 12:19 AM Post #5 |
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| clarkdw | May 8 2012, 06:56 AM Post #6 |
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I have successfully used several adjustable cam sprockets that used only the crush of the bolt to prevent the cam from changing timing. These were used on race engines with lots of lift and aggressive valve accelerations that put a lot of load on the rotating mount. The most difficult part is making sure the timing is still correct when you tighten the bolt. To set it properly using an adjustable sprocket you really need a degree wheel or a digital inclinometer along with a dial indicator for the valve. Same logic applies to our crankshaft sprockets. There have been a number of instances of wallowed out keyways on the cranks of engines posted here in the last while. IMHO these are all caused by not correctly tightening the bolt that holds the sprocket. The key on the crank and the dowel on the cam are there to locate the part till the main bolt is tightened up. That is what prevents movement of the parts. Budget constraints on my race cars precluded buying the fancy vernier adjustable sprockets. Also, turning the sprocket clockwise while holding the cam still will retard the cam, not advance the cam. You want to rotate the sprocket anti-clockwise while holding the cam still. That will advance the cam which is what I assume you want to do. |
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| Coche Blanco | May 8 2012, 12:23 PM Post #7 |
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Troll Certified
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So you "wallow out" the dowel pin hole a little, stick a screwdriver in the holes in the cam, turn the sprocket left till it hits the right side of the hole, and tighten it down?
Edited by Coche Blanco, May 8 2012, 12:24 PM.
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| clarkdw | May 8 2012, 02:05 PM Post #8 |
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You can use offset dowels or ground down dowels. The offset dowels move it and do lock it in place. You need to know how much offset is required and then make a dowel on the lathe. Then you need to put the dowel in the hole in the correct orientation for the timing change you need. For testing you can make a number of dowels at different offsets. Calculating the amount of dowel offset is simply knowing what the distance the dowel is from the center of the cam, figuring out the circumference of a circle that size and dividing that distance by 360 to find the amount of offset for each degree of change. Using ground down dowels uses the same calculation to figure out how much you want to grind down the outer portion of the dowel to allow cam movement in the correct direction. This method won't lock the cam while you are tightening the bolt so you need to check the timing after everything is tightened up. |
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| Coche Blanco | May 8 2012, 02:22 PM Post #9 |
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Troll Certified
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That is a great idea, something I never would have thought about. Now, is it a 5* advance on the cam side, or a 10*? I've always leaned towards 5*... |
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| socal geo garage | May 8 2012, 09:27 PM Post #10 |
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the cam wheel ended up about 1/2 tooth advanced ,i used a old steel gasket sliver to space it out bent it down and secured with the wheel bolt .Its going to be hard to tell if the wheel mod worked at the same time i am doing new pistons rings rod bearings and this ported head. 40 thousands milled ss valves![]()
Edited by socal geo garage, May 8 2012, 11:37 PM.
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| clarkdw | May 8 2012, 11:17 PM Post #11 |
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One full tooth on the camshaft is 18 degrees of crankshaft timing so 1/2 a tooth is 9 degrees, right? CB: The measurement of cam timing is always done in crankshaft degrees and two crankshaft degrees is one degree of the camshaft so you are correct. 5 degrees on the camshaft side is equal to a 10 degree change in camshaft timing. |
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| socal geo garage | May 8 2012, 11:41 PM Post #12 |
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i don get it thanks
Edited by socal geo garage, May 8 2012, 11:47 PM.
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| Coche Blanco | May 9 2012, 12:11 AM Post #13 |
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Troll Certified
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Now, if I had access to a lathe... I feel like they would be easier to install than a redrilled cam gear, and you woudn't need cores. |
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| socal geo garage | May 9 2012, 12:57 AM Post #14 |
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see my new post problem with rebuild |
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| socal geo garage | May 11 2012, 01:20 PM Post #15 |
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new fel pro cam seal worked on leak ,everything worked out great on this rebuild low end slightly more ,lots of power in mid and top like a mini turbo in there.
Edited by socal geo garage, May 11 2012, 01:21 PM.
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thanks
9:40 AM Jul 11