Electronic Ignition Conversion (HEI)
Re-printed from the Club’s newletter and only sent to club members
This conversion is for Jeepsters that have the 225 V-6 Buick engine. First you need to purchase a complete 231 V-6 odd-fire HEI distributor from a 1976 Buick, Pontiac or other GM car. Do not forget the spark plug wires and ring! Next you will need about three feet of #14 automotive wire, one female spade terminal and one eyelet terminal with a small diameter hole. Pick up about three feet of 1/8″ vacuum hose (new or used) and the same time, get three wire hold down fasteners that will be used to secure the dist. wire to the two upper valve cover bolts and one for fire wall after drilling a 1/8″ hole for the fastener’s bolt. Now you will need to go down to your Buick or GM dealer and get/order the front left intake manifold bolt that is located directly under the distributor. This special Torx button bolt is used because of the close clearance between the distributor housing and the intake manifold bolt.
Carefully remove the dist. cap and wires and then by bumping the ignition key, bring the distributor’s rotor up to number one wire terminal position. This is about 10:00 or 11:00 o’clock. Look down at the timing marks and make sure the pulley/damper timing mark is lined up with the “0” mark on the timing case cover. You can help line up the timing marks by using a wrench and socket on the vibration damper’s bolt. All this finagling around will give you Top Dead Center, (TDC).
Now remove the negative battery cable and proceed to remove the distributor by first removing the dist. hold down bolt and bracket, disconnecting the coil wire, primary coil wire, and pulling the spark plug wires off the spark plugs. Pull the dist. out as one unit. Make a mental note as to where the rotor is positioned and hot the rotor moves counter-clockwise as the dist. is being pulled out.
Now comes a little work to prep the dist. area to accept the HEI dist. One problem that a few people had is the fuel lines needed to be repositioned so as to provide adequate clearance for the dist…. usually one simply needs to move them over towards the left fender a little. A couple of us became real ambitious and ended up no longer having the fuel lines running across the intake manifold, down to the fuel pump and then back up to the carb. This makes it REAL nice for tightening the dist. hold down bracket bolt and working with the smog and P/S pump.
Remove the front left intake manifold bolt and install the new Torx bolt and tighten it to 45 ft/lbs. You might need to buy the Torx bit if you don’t already have one. Take the new dist., without the cap on, and CAREFULLY slip it into place. At this point, don’t worry about having the rotor pointing at TDC…#1. You will now find that the bottom of the dist. housing hits the very edge of the intake manifold… right in front of the torx intake manifold bolt. Yep, you guessed it, you need to grind the edge of the manifold so that the dist. and CAP will rotate freely. So pull the dist. back out, stuff a rag down the dist. shaft hole and start grinding. I borrowed a 4 inch grinder and finished the job in five minutes. This included installing the dist. many times to check my progress. If you stick your finger under the edge of the manifold, you will feel that it has a lip protruding out past the engine’s block so grinding this area is NOT going to hurt anything at all. I ground this lip until the manifold edge was flush with the block. I then put a slight taper (towards the new bolt) on the manifold’s edge.
Clean up all metal filings and then reinstall the dist. and this time, point the rotor at the #1 position. If you are having a hard time getting the dist. to drop into the #1 slot, put the dist. down in the hole about 1/3 to 1/2 of the way down and then turn the rotor clockwise just a little and then push it down until it is pointing at #1. Make sure that the dist. housing is seated flush with the timing case cover.
Reinstall the hold down bracket and bolt and tighten it up snug. Place the dist. cap on the dist. and install the spark plug wires on the spark plugs. Don’t forget the spark plug wire’s hold down ring and install the wires in the correct firing order. The dist. cap firing order is not the same as the old 225 dist… So you might need to find out the firing order from a manual of the car you got the dist. from. Once again, check that the dist. and cap does not rub on the intake manifold.
Now hook up the vacuum advance hose to the dist.’s vacuum advance port. Take #14 gauge wire and crimp on the female spade terminal. Push the connector onto the dist. cap’s terminal labeled “BAT”.. Carefully route the wire over to the left value cover and follow the top of the valve cover and then go up the fire wall to where the ballast resistor is located. The ballast resistor is a white rectangle ceramic item that is just behind the air cleaner, but it is mounted on the upper part of the fire wall. It should have two green wires connected to it. One goes to the old dist. coil and the other goes to the ignition key.
Remove both wires from the resistor. Then turn on your ignition switch to the run position…after hooking up the neg. battery cable….and with a test light, find which of the two wires is hot. Place the “hot” wire back on to the ballast resistor’s far left terminal. Now bring the new dist. wire to the “hot” terminal and cut any excess wire off, slide the 1/8″ vacuum hose over the wire until it is about two inches from where the wire is connected to the dist. “BAT” terminal. Cut the other end of the vacuum line about two inches short of the wire’s end. Place the eyelet terminal onto the end of the wire and crimp it in place. Fasten BOTH the hot wire and the new dist. wire together on the SAME far left terminal. Leave the other green wire disconnected from the ballast resistor…tuck it into the main wiring loom.
Remove the upper two valve cover bolts, slip the two wire fasteners over the vacuum/wire and secure them down with the two valve cover bolts. This will keep everything in place. If needed, use the third wire fastener on the fire wall. Buy a self-taping sheet metal screw to hold the third wire fastener in place. Remove the old dist. coil. Now your ready to start the engine and from here it is just setting the timing to normal specs and re-checking to make sure everything you touched is working safely, won’t rub or come loose.
The results should be recognized right away. Morning start ups are really noticeable. The engine runs smoother and has quicker acceleration and a little better gas mileage. It will help out in high altitude by keeping the engine from running as rich. This swap is worth the price!
Note 1: Gap the spark plugs at 40/45 instead of 35.
Note 2: One person installed an adjustable vacuum advance unit that had the vacuum port tube pointing straight out the end and when the vacuum hose was connected to it, the fan would just touch the hose. This was simply cured by buying a 1/2″ fan spacer. This person had a six blade fan and not a stock one.
Note 3: You can purchase a centrifugal advance weight and spring kit, thus making it possible to “dial-in” the dist.’s advance curve for the RPM range you prefer to have full dist. advance.