hello everyone, new member here, have a stock 85, replacing the timing set using a haynes manual. freaking out, it says to set the cam gear dot at 12 o'clock and the crank at 12. never seen a 350 this way. tell me they are wrong

 

The crank gear will rotate 2x for every 1 revolution of the cam gear. It the cam gear dot is at 12:00 and the crank gear is at 12:00, it will be the same as putting cam gear at 6:00 and the crank gear at 12:00.No problem either way.

 

The correct way is line up the dots. *BUT* doing it this way, and then installing the distributor will put the distributor 180 degrees out. If you do it the way your manual says, you can nstall the distributor and it will be in the correct way.

 

The timing sprockets are installed with the #1 piston at TDC. The #6 piston is at TDC at the same time as #1. It is the valve opening and closing (camshaft position) that determines whether that TDC is at the beginning of the power stroke or the intake stroke. With the dot of both sprockets at 12:00 o'clock, the camshaft is oriented for the #1 cylinder to be starting the power stroke. With the crank sprocket at 12:00 o'clock and the cam sprocket at 6:00 o'clock the cam is oriented for the #6 cylinder to be starting the power stroke, and #1 to be starting the intake stroke. It is much easier to be sure of the dot alignment at the 12:00 and 6:00 positions (dot to dot). Just be sure to turn the engine over 1 revolution, to get the #1 piston to TDC on the power stroke, when you install the distributor. If you have the distributor out. The easiest way to do this, if you haven't progressed beyond this point, is to rotate the engine so the sprockets are dot to dot, before you remove the timing components, and just install the new parts, as the old came out, making any minor adjustment due to the slop in the old chain.

RACE ON!!!

 

Exactly. And once the new chain and sprockets are on, rotate the engine 360 degrees with the crank bolt, and ensure that everything lines back up and you aren't a tooth off before putting the cover back on. Few things would suck as bad as having to take it back apart again. Measure twice, wrench once.

I just recently did the timing chain on my 84. Not a fun job (mostly due to my old aching back), but not particularly difficult either. When I disassembled it, I lined it up with the crank at 12:00 and the cam at 6:00, dots matching. To me it's much easier to ensure that you aren't a tooth off this way.

If the distributor hasn't been removed, your ignition timing will be exactly as you left it...but may be slightly advanced if it was set with a sloppy chain in place. Always check ignition timing after you finish.

On a side note, I'm assuming you're replacing the crank sprocket. Use a large socket to install the new crank sprocket, and be EXTRA sure it seats fully against the snout of the crank. I also recommend using new woodruff keys in the crank.

How many miles are on this motor? I swapped my chain at 145K and it was VERY sloppy. I noticed an immediate improvement in idle quality, vacuum signal, and acceleration, particularly low end torque.

Good luck with it.