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cam wheel mod
Topic Started: May 7 2012, 12:48 AM (1,709 Views)
socal geo garage
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clarkdw
May 8 2012, 06:56 AM
sam2007
May 7 2012, 12:48 AM
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?
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.

I was thinking backwards o no your right thanks. question would the cam and wheel marks not change from stock?

Update wow it worked big time . i reset computer by disconnecting the battery and set stock first advance mark on the dizzy. and started it idles so smooth at first i thought it was going to stall, NOT its just smooth idle took a spin around the block and knew it was good,just what i was looking for > just a MM or two on the gas pedal is all thats needed.thanks for your help sir. so whats next maybe an XFI cam if anyone wants to sell one pm me i can offer cash and a very good condition stock cam from a 1997 1.0 and two cam wheels one from a 1995 and one from a 1997 or a complete head with cam and wheel will also consider 3tech xfi or delta xfi cam.
Edited by socal geo garage, May 14 2012, 08:28 PM.
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socal geo garage
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clarkdw
May 8 2012, 06:56 AM
sam2007
May 7 2012, 12:48 AM
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?
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.

tried that and the belt does not line up.then what turn the lower crank gear? if i turn it then what way? Maybe just best to slot the wheel and turn the cam clockwise ?
Edited by socal geo garage, Aug 4 2012, 02:54 PM.
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clarkdw


Leave the crank and cam tied together with the belt. The relationship of the crank and cam sprockets does not need to be changed.

You are correct in suggesting to rotate the cam only in the clockwise direction. Don't forget that for each degree you rotate the cam it is a two degree change in the timing. The crank rotates two degrees for each degree of cam rotation and the cam timing number is based on crank degrees.
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socal geo garage
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clarkdw
Aug 5 2012, 01:08 AM
Leave the crank and cam tied together with the belt. The relationship of the crank and cam sprockets does not need to be changed.

You are correct in suggesting to rotate the cam only in the clockwise direction. Don't forget that for each degree you rotate the cam it is a two degree change in the timing. The crank rotates two degrees for each degree of cam rotation and the cam timing number is based on crank degrees.
clark thanks for taking the time here > my motor on my 94 xfi is completly apart and crank has spun a few times am i correct in assuming the cam has to do with compression stroke and not the crank, because ive noticed before the crank mark comes around to line up on compression and exhaust strokes. TDC. thanks again ... what i am asking is when i put the crank gear back to the the mark on the oil pump it does not matter its the head/cam and piston positition that make compression stroke . number one exhaust and intake valves closed? and number one on the cap and rotor?
Edited by socal geo garage, Aug 5 2012, 01:25 AM.
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clarkdw


As long as #1 piston is at tdc ie: crank timing mark lined up then whether the cylinder is on compression or exhaust is then determined by where you set the cam. Line up the marks on the two sprockets and you will be fine.
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