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Adrnln
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Joined: 02 Oct 2006
Posts: 3
214.98 points
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 Posted: Mon Oct 02, 2006 6:05 pm Post subject: Lunati timing marks wrong? |
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First time here, hope to make some new friends.
I am working on a neighbors old chevy 1 ton. New lunati cam, lifters and gears. The problem I'm having is when I align the cam gear at 6 and the crank gear at 12, I am 180 degrees off. All the chevrolets I've ever worked on use this alignment. Is lunati just different or am I doing somethinh wrong.
Just to clarify myself, with this alignment, The #1 piston is not on tdc, when I crank the engine over by hand just before 180 deg. I feel the #1 cylinder pressure up. Are there any chevrolets you guys know of that align the cam gear at 12oclock and the crank at 12 oclock.
Thanks in advance for any help |
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af2
Member
Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points
1933 Willys Coupe
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| Posted: Mon Oct 02, 2006 7:41 pm Post subject: Re: Lunati timing marks wrong? |
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| Adrnln wrote: | First time here, hope to make some new friends.
I am working on a neighbors old chevy 1 ton. New lunati cam, lifters and gears. The problem I'm having is when I align the cam gear at 6 and the crank gear at 12, I am 180 degrees off. All the chevrolets I've ever worked on use this alignment. Is lunati just different or am I doing somethinh wrong.
Just to clarify myself, with this alignment, The #1 piston is not on tdc, when I crank the engine over by hand just before 180 deg. I feel the #1 cylinder pressure up. Are there any chevrolets you guys know of that align the cam gear at 12oclock and the crank at 12 oclock.
Thanks in advance for any help |
Should be cam at 12 and crank at 12 at #1 tdc or lined up at #6 tdc. |
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10sec.et
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Joined: 29 Mar 2006
Posts: 3477
Location: Houston,Texas
346819.60 points
1969 Oldsmobile Cutlass
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| Posted: Mon Oct 02, 2006 11:11 pm Post subject: Re: Lunati timing marks wrong? |
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| af2 wrote: | | Adrnln wrote: | First time here, hope to make some new friends.
I am working on a neighbors old chevy 1 ton. New lunati cam, lifters and gears. The problem I'm having is when I align the cam gear at 6 and the crank gear at 12, I am 180 degrees off. All the chevrolets I've ever worked on use this alignment. Is lunati just different or am I doing somethinh wrong.
Just to clarify myself, with this alignment, The #1 piston is not on tdc, when I crank the engine over by hand just before 180 deg. I feel the #1 cylinder pressure up. Are there any chevrolets you guys know of that align the cam gear at 12oclock and the crank at 12 oclock.
Thanks in advance for any help |
Should be cam at 12 and crank at 12 at #1 tdc or lined up at #6 tdc. |
i think its Fords that are TDC with cam and crank gears "dot to dot".
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| af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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clay
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Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points
1972 Chevrolet Nova
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| Posted: Tue Oct 03, 2006 4:33 am Post subject: |
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| How do you think you are 180* off? Even if you put the timing marks both at the 12 o'clock postion, if you turn the crank one revolution, then the cam should be at 6 o'clock with the crank back at 12 o'clock due to the 2:1 reduction. Dot to dot should work but I think the dot to dot postion usually puts #1 in the overlap position (exhaust closing / intake opening) and not the compression stroke which may be confusing you. Clay |
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af2
Member
Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points
1933 Willys Coupe
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| Posted: Tue Oct 03, 2006 9:54 am Post subject: |
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| clay wrote: | | How do you think you are 180* off? Even if you put the timing marks both at the 12 o'clock postion, if you turn the crank one revolution, then the cam should be at 6 o'clock with the crank back at 12 o'clock due to the 2:1 reduction. Dot to dot should work but I think the dot to dot postion usually puts #1 in the overlap position (exhaust closing / intake opening) and not the compression stroke which may be confusing you. Clay |
Clay, Exactly true which means #6 is tdc on the compression stroke with the marks dot to dot. |
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Adrnln
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Joined: 02 Oct 2006
Posts: 3
214.98 points
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| Posted: Tue Oct 03, 2006 4:27 pm Post subject: |
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Yes, both valves move almost immediately depending on which way you turn the crank. So, I learned something today, I think. I was under the impression that when you have the #1 cylinder on the compression stroke at TDC that the marks on the cam and crank gear would be at 6 and 12 oclock. So...I am wrong.
You have eased my mind. I spent two days trying to figure what was wrong. I initially just installed the parts and was in the process of running the valves one cylinder at a time when I noticed what I thought was a problem. So I am good to continue the installation.
THANKS, to all who replied to my post, I appreciate your imput.
Allen |
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clay
Moderator
Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points
1972 Chevrolet Nova
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| Posted: Tue Oct 03, 2006 6:53 pm Post subject: |
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| Glad we could help! Clay |
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