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Cam/Lifter Install - Clairification on Gear Set Uo

Posted By: HogRidinFool

Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 03:07 PM

I'm installing a new cam. lifter and tinming chain on a '70 383. I've got it appart and doing the cleaning and painting thing. My question is, when installing the new timing chain the instructions that came with the set (from Mancincis) says the dot on the cam gear is at 6:00 and the crank gear is at 12:00 and a friend has also told me that. The counter guy at Mancinis says the dots on both gears should be at 12:00 and I've read that in an archive posting. Just looking for clairification.

Also, when I disassembled everything, the #1 piston was up, the rotor was poiting at #1 and the dots were in the 6 & 12 positions. Thanks
Posted By: lewtot184

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 03:29 PM

cam gear dot 6 o'clock, crank gear dot 12 o'clock, #1 piston at TDC.
Posted By: buildanother

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 03:30 PM

It is easiest lining up dots with crank at 12 oclock and cam dot at 6 oclock, BUT that is set to fire cyl #6. When both dots are at 12 oclock, then it can be set up to fire cyl #1.
Posted By: 1_WILD_RT

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 03:36 PM

Quote:

It is easiest lining up dots with crank at 12 oclock and cam dot at 6 oclock, BUT that is set to fire cyl #6. When both dots are at 12 oclock, then it can be set up to fire cyl #1.



Correct!! As long as you set the distributor to either fire # 6 without the engine turning or turn the engine over one crankshaft rotation so it's at TDC #1 before you drop the distributor in all is good..
Posted By: MoparforLife

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 03:48 PM

Quote:

Quote:

It is easiest lining up dots with crank at 12 oclock and cam dot at 6 oclock, BUT that is set to fire cyl #6. When both dots are at 12 oclock, then it can be set up to fire cyl #1.



Correct!! As long as you set the distributor to either fire # 6 without the engine turning or turn the engine over one crankshaft rotation so it's at TDC #1 before you drop the distributor in all is good..


Most of the time the cam/crankshaft installation position means nothing after the cam is installed as for the firing position of the number 1 piston. Yes installed at 12/6 places number 6 in the firing position but most engines after the cam is installed have the crankshaft rotated from that position for one reason or another so the position at cam installation is rather insignificant after the gears and chain are installed whether dot to dot or degreed. I have yet to see one that isn't rotated after the installation of the cam and before firing. Always check the TDC firing position of the number one piston before instillation of the intermediate gear and distributor.
Posted By: Dodgem

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 03:56 PM

either way is fine but roll motor over multiply times to check and re check!! things can look might different after rolling and bringing back in line.
moreso down in the car.
Posted By: RapidRobert

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/22/09 07:43 PM

With the dots at 6 o'clock & 12 o'clock #6cyl is at TDC compression ready to fire. 12 o'clock & 12 o'clock #1 cyl is at TDC compression & ready to fire. It's confusing because the pics in shop manuals show 6 o'clock & 12 o'clock which would lead a person to believe that Ok you R&R your timing set, line the dots up like shown & you're ready to time the dist to #1 . 6o'clock & 12 o'clock are closer than 12 & 12 & easier to line up either visually or with a straight edge but WHY the manuals neglect to inform you that you are on #6 tdc compression or else that you then need to rotate it (1) revolution is beyond me. Your last sentence, when you tore it down & had it at 12 & 6 the rotor would have had to have been pointed at wherever you had the #6 plug wire on the cap
Posted By: HogRidinFool

Re: Cam/Lifter Install - Clairification on Gear Set Uo - 03/23/09 12:33 PM

Update:

First off, thanks to all who responded, I learn so much from this forum. A buddy stopped over and we think we got everything set up correctly. I'm about a couple hours of install work of being able to fire it up. I'll keep you posted if we did good. Thanks again to all!
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