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'76 FW Brougham d'Elegance (R.I.P.), '75 SDV (57k,2nd owner)
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Discussion Starter #1
I have a 68 472 with '75 HEI swapped. it will not fire up. Need a diagram or tutorial on where rotor needs to be pointed and what cylinder. Ive read it is cylinder 1 or it can be #4. My cam and crank gear dots are both pointed at 12 oclock position.
 

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95 FWB 81SDV 96 FWB 94 Fleetwood
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The 12v wire to the old distributor has a resistor in it for the old points system. this wire has to be replaced. as far as getting the distributor on the right tooth , take out a spark plug , stick your finger to block the spark plug hole and have someone jog the motor til it blows out your finger and stop... now adjust the distributor , by pulling it in and out so the rotor is pointed to the wire of the spark plug you pulled out.
 

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'76 FW Brougham d'Elegance (R.I.P.), '75 SDV (57k,2nd owner)
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Discussion Starter #3
The 12v wire to the old distributor has a resistor in it for the old points system. this wire has to be replaced. as far as getting the distributor on the right tooth , take out a spark plug , stick your finger to block the spark plug hole and have someone jog the motor til it blows out your finger and stop... now adjust the distributor , by pulling it in and out so the rotor is pointed to the wire of the spark plug you pulled out.
Forgot to mention that this 472 is swapped into an 80 c20 chevy truck, which came factory HEI equipped. All the points references u made dont apply to this
 

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I have a 68 472 with '75 HEI swapped. it will not fire up. Need a diagram or tutorial on where rotor needs to be pointed and what cylinder. Ive read it is cylinder 1 or it can be #4. My cam and crank gear dots are both pointed at 12 oclock position.
On most engines, that's #1 compression. On some, crank gear at 12 and cam gear at 6 is #1 compression. As said, a finger OVER (not "into") the #1 spark-plug hole, and have someone crank the engine...when pressure starts squeezing out from under your finger, you're approaching #1 TDC Compression.

What you actually WANT, however, is to be ~10 degrees advanced from TDC. Any amount from 0 to 18 degrees advanced will work. If the timing spec for your engine is "6 BTDC" you could happily put the damper at the 6 degree advanced mark and be fine. Set the damper at whatever you want the initial timing to be.

THEN, drop the distributor into the hole so that the rotor tip points to the #1 terminal of the distributor cap, while the distributor vacuum advance points in the proper direction. Yeah, you can put the cap on the distributor, find #1 terminal on the cap, and then paint a stripe directly below, on the aluminum housing of the distributor for reference. Yeah, the rotor will turn some as the helical distributor gear meshes with the helical cam gear. You want the distributor to seat down so that the bottom of the distributor also meshes with the oil pump drive. Both the rotor and the housing need to mostly-align with their respective parts.

LASTLY, rotate the distributor housing SLOWLY AND CAREFULLY with the rotor OFF, so that you can SEE the "teeth" on the pickup coil and the reluctor. You should also be able to feel their magnetic attraction. You want to get those teeth so the "points" of the teeth perfectly align. Again, this can be done by the feel of the magnets, you'll know when you're close. When they're aligned as best you can get, tighten the hold-down bracket at the distributor base so it's snug but not fully tight. Install rotor, cap, whatever else you disassembled EXCEPT for the vacuum advance hose. Shove a golf tee, or small machine screw, or RTV applicator nozzle, or whatever in the loose end of the vacuum advance hose to plug it.

To recap: You now have:
The damper some few degrees advanced from TDC Compression
The teeth of the pickup coil and reluctor aligned
The rotor generally pointing to #1 spark plug wire terminal at the distributor cap
The vacuum advance pointing generally in the proper direction, but with the hose disconnected from the canister and plugged.


Connect timing light. Pour some fuel into the carb float bowl vent if the float bowl is dry. Open the throttle about half-way, then allow it to close. Choke should shut, and throttle will be on fast-idle. Start the engine. Should fire immediately. You should be within a few degrees of the initial timing. Set initial timing to perfection using the timing light as soon as the engine warms enough to be at curb idle instead of fast idle. Fully tighten the hold-down bolt, and re-connect the vacuum advance. Shut the hood. Have a beer. You're done.

Do this a few times, develop a "feel" for the alignment of the teeth, and you can get the timing within a degree or two without ever starting the engine. This procedure is called "Static timing" because the engine doesn't have to be running to get close to proper initial timing.
 

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This figure will get you started. The HEI module can be bad, even if its new. Same with an aftermarket coil. I would trust a real GM HEI module from a junkyard before I would trust any import module.
472 firing order.png
 
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