timing issue

[camjck89]

hey guys can anyone give me instructions on how to properly install my hei distributer. i have put it in exactly like the old points system and done everything but wire it, however im being told that it may be off 180 degrees and the timing chain might go in it . what im wondering is how do i fix it with out making it go "boom". i dont know alot about timing and getting the engine at tdc and all. ii just figured as long as its in like the other i could just tweak it to make initial and total timing correct. if anyone can help then id appreciate it

[cdowns]

if the motor has not been moved since removing the points dizzy it will go in the exact same as the old one came out

[camjck89]

i took out the old one , put the new one in the same way . thought i had the wiring down tried cranking and nothing. but i want to make sure its in right before i know its firing

[LockDoc]

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Don't know if you realize it or not but you can't use the points distributor wiring. You have to have a 12 volt power source that is hot when the ignition is on. You can find one on the fuse block. It should say "Ignition Unfused"

LockDoc

[camjck89]

yeah i have 10 gauge wire going from the batt. connection on the distributor to the unfused ign. of the interior fusebox

[trz1000]

An easy way to tell if you're 180 out is to pull the valve cover on the driver side and the distributor cap. Keep an eye on the valves for #1 and rotate the motor (by hand or with a remote starter). The distributor should be clocked to fire when both valves are closed. If not, you need to static time the motor.

Hope this helps.

[camjck89]

Originally Posted by trz1000

An easy way to tell if you're 180 out is to pull the valve cover on the driver side and the distributor cap. Keep an eye on the valves for #1 and rotate the motor (by hand or with a remote starter). The distributor should be clocked to fire when both valves are closed. If not, you need to static time the motor.

Hope this helps.

define static time, sorry

[trz1000]

Static timing the motor is the process of finding TDC on the compression stroke then setting the timing while the motor is off. The compression stroke is when both valves are closed. I set it at 10 degrees BTDC but there may be other preferences. You do this by rotating the motor to 10 BTDC using the timing tab on the timing cover and the notch in the harmonic balancer. Then install the distributor so the rotor is in the proper orientation (i.e. lined up with #1 plug terminal on the cap) then turn it (as if you were timing it) so that it will fire at 10 BTDC.

Take your time lining everything up and the motor will fire but you'll still have to adjust the timing once the motor is running so don't fully tighten the hold down yet.

The timing mark on harmonic balancer will go by twice in the 4 stroke cycle. Once on the compression stroke and once on the exhaust stoke. If you have the distributor firing on the exhaust stroke you're 180 degrees out of time and the motor will never fire.

There are two easy ways to tell if you're on the compression stroke. One is to remove the valve cover and watch the #1 valves as the balancer mark passes 0 degrees. If they're both closed then you just completed the compression stroke. Another way is to pull the #1 plug and crank the engine with your finger over the hole, if there's pressure building in the cylinder as you approach 0 degrees, you're on the compression stroke.

TDC - top dead center (this is where the piston is at the very top of the cylinder wall, where it makes the transition from going up to going down)

BTDC - before top dead center

There is a real good write up on timing here:

http://67-72chevytrucks.com/vboard/s...d.php?t=290498

Don't be intimidated, it's a lot easier than it sounds.