The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - How can I turn the crank and cam so the timing marks line up right?

**71CHEVYSHORTBED402** · 05-27-2018, 05:11 PM

71 C-10 402. Not a rebuild, just a new oil pump and timing gear.

Just pulled the timing chain and gears off, and something escapes me for installing a new chain and gears.

Each gear has a timing mark. As long as those marks face forward the gears only insert one way. That's because there's just one key way on each snout.

As I understand it, assuming the engine is straight (which it's not in the picture), when you install a timing chain the cam gear mark should be at 6-O-clock, and that lines up to crank gear mark at 12 O-clock. In other terms, the timing marks line-up vertically.................I assume the cam and crank turn independently without a chain (clockwise). As it sits the marks on the gears did not meet per the description. How do you safely rotate the crank and cam so the marks line up correctly for installing a chain?

I realize the spark plugs should be removed beforehand. Can't use the flex plate to turn the crank, because the block is on a stand. No I'm not going to use the crank bolt.........or a pipe wrench (yikes). Thank you.....

05-27-2018, 05:11 PM	#1
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,157	How can I turn the crank and cam so the timing marks line up right? 71 C-10 402. Not a rebuild, just a new oil pump and timing gear. Just pulled the timing chain and gears off, and something escapes me for installing a new chain and gears. Each gear has a timing mark. As long as those marks face forward the gears only insert one way. That's because there's just one key way on each snout. As I understand it, assuming the engine is straight (which it's not in the picture), when you install a timing chain the cam gear mark should be at 6-O-clock, and that lines up to crank gear mark at 12 O-clock. In other terms, the timing marks line-up vertically.................I assume the cam and crank turn independently without a chain (clockwise). As it sits the marks on the gears did not meet per the description. How do you safely rotate the crank and cam so the marks line up correctly for installing a chain? I realize the spark plugs should be removed beforehand. Can't use the flex plate to turn the crank, because the block is on a stand. No I'm not going to use the crank bolt.........or a pipe wrench (yikes). Thank you..... Attached Images __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring the truck from ground up. With assys, the guide accts for 1000s details, OEM identifications & part numbers, written in short order. 700+ images of assm., illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025