How to Install an Engine Ignition Distributor, Set Timing, Select Gear, Find Top Dead Center

How to Install an Engine Ignition Distributor, Set Timing, Select Gear, Find Top Dead Center

Male 1: Brought to you by JEGS. Male 2: One of the most common jobs involved
in working on a classic muscle car is installing the distributor. Whether you’re removing and replacing the
existing distributor on an engine or setting up one for the first time on a new build,
doing it right is critical to proper engine operation. The distributor is driven by a gear on the
camshaft and controls your engine’s ignition timing. It also drives your engine’s oil pump via
an intermediate shaft. Both of these vital functions require a bit
of care during installation in order to make sure things are properly aligned. Let’s start by looking at the installation
of a new distributor. We’re using a classic Ford Mustang as an example
but the process is the same for any brand of vehicle. Any new distributor needs to have a drive
gear that is compatible with the camshaft installed in the engine in order to prevent
premature wear and potentially fatal damage to the camshaft. There are four common types of distributor
gears: cast iron, hardened steel, also known as melanized, bronze, and composite. Most aftermarket distributors are supplied
with hardened steel gears which may not be correct for your application. If there’s any doubt, give JEGS a call and
speak to a tech for a distributor gear recommendation. In order to install your new distributor you’ll
need to know your engine’s firing order and which direction the distributor turns. Locate cylinder number one, and with all the
spark plugs removed turn the engine over by hand until the timing mark on the balancer
approaches zero degrees or top dead center. Put your thumb tip over the spark plug hole,
and as the piston rises you’ll feel pressure on the compression stroke. If you don’t, keep turning the crankshaft
through another rotation until you do. This will prevent installing the distributor
180 degrees out of phase. Set the balancer to the zero degree mark and
you’re ready to install the distributor. Decide which terminal on the cap will be your
number one cylinder and turn the rotor until it’s aligned with that post, taking into account
how you want to position the spark plug wires relative to the distributor and the location
of the vacuum advance, if present. Apply some assembly lube or fresh motor oil
to the distributor gear to prevent unnecessary wear when you first start the engine. Because the distributor drive gear is helical,
the rotator will want to turn as you insert the distributor into the engine. To take this into account, position the rotor
ahead of the number one terminal in the rotation order, halfway between the previous terminal
and where you want it to end up. As you lower the distributor, it will rotate
against the stationary cam gear and end up in the desired position. More often than not, the distributor will
not go all the way into position on the first try because the bottom of the distributor
isn’t aligning properly with the oil pump intermediate driveshaft. One way to solve this is to use a long screwdriver
or socket and extension to slightly rotate the shaft by hand so that it aligns with the
drive on the bottom of the distributor when they first make contact. If you’re removing and replacing an existing
distributor, you can save yourself time and trouble by marking the position of the distributor
relative to the block and the rotor relative to the distributor before removing it. If the crank isn’t turned while it’s out,
lining up these marks again when you replace the distributor will bring you very close
to the same timing and the oil pump driveshaft will remain in alignment. Once your distributor is properly seated you
can connect the spark plug wires paying attention to your engine’s firing order and distributor
rotation direction. To set base timing, leave the vacuum advance
disconnected and plugged. Tighten the distributor clamp just tight enough
to allow adjustment of the distributor by hand and crank the engine. Using a timing light, advance the timing before
top dead center a few degrees until the engine fires then set your desired base timing. A conventional timing light will require you
to read degrees of advance off the markings on the balancer, while a dial back light will
let you set your desired timing at the gun and then simply align the top dead center
mark with the pointer. Once your timing is set, lock down the distributor
and don’t forget to reconnect the vacuum advance. For more information about distributor selection,
in depth instructions and technical advice visit on the web, or give us a call
at (800) 345-4545 to order toll free around the clock every day. Male 1: Brought to you by JEGS. Lifetime support, complete customer satisfaction,
delivering performance since 1960.

About the Author: Michael Flood


  1. My truck was running very rough, and would almost die when I push the accelerator. My first thought was this is caused by a faulty ignition control module. When I pulled the distributor cap everything was so rusty I decided to replace the distributor with a new Duralast distributor. After installation I got the truck to start twice but it died right away. I noticed that after cranking if I left the key in the on position it sounds like the fuel pump is running, and there's a arcing or buzzing sound coming from the distributor. I removed the larger electrical connection from the ignition control module and the arcing sound stops. I have no idea what is causing this, or how to correct it. Any ideas or recommendations are appreciated.

  2. Question i am installing new timing chain…when crankshaft and camshaft gear marks are lined up … Is that also top dead center on compression stroke? i need to install my distributor correctly on my chevy 4.3..just want to make sure…thanks

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