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02-08-2018, 03:00 PM | #1 |
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Join Date: Feb 2012
Location: Las Vegas, NV
Posts: 1,260
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Tdc #1 heads off?
Am adjusting valves and thought I would go through them a second time before I put the heads back on, as soon as I checked the valves on #1 I discovered the adjustment was way off. I understand the cam runs at half speed so why are the intake and exhaust valves both on their seats and piston at TDC #1 whenever I turn the the crank to TDC #1 as marked on my pulley? I know everything is working as it should because every time I come around to TDC #1 the gap on the valves changes. What should I also look for to confirm TDC on compression cycle?
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02-08-2018, 03:04 PM | #2 |
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Join Date: May 2010
Location: Oshkosh, Wi
Posts: 4,516
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Re: Tdc #1 heads off?
At TDC on the firing stroke, both valves are closed. You need to make two revolutions of the crankshaft to get back to the same condition
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02-08-2018, 03:32 PM | #3 |
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Location: Everett, WA
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Re: Tdc #1 heads off?
After the intake opens and then closes you are on the compression/firing stroke.
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02-08-2018, 03:39 PM | #4 |
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Join Date: Feb 2012
Location: Las Vegas, NV
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Re: Tdc #1 heads off?
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02-08-2018, 03:41 PM | #5 |
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Join Date: May 2010
Location: Mid coast Maine
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Re: Tdc #1 heads off?
There probably is a better right up.
Watch the intake open turn to TDC both valves closed, now adjust #1 , Then turn 90 degs and do next cylinder by firing order. The intake will be just opening the next TDC is compression stroke. |
02-08-2018, 03:47 PM | #6 |
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Re: Tdc #1 heads off?
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02-08-2018, 04:03 PM | #7 |
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Join Date: May 2010
Location: Chester Vt
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Re: Tdc #1 heads off?
After the compression stroke the next time the piston is at TDC BOTH valves are open. This is called "split overlap" and is a good way to check if the cam is in right.
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