HEI help, ideas, thoughts, throw it away ?

Sounds like you are too far advanced.............

Remember backfire out the carb = advanced
Backfire out of the pipes = retarded

 

Fortunately my jeep had the HEI stock from factory so i didnt have this much trouble but..

One possible thing with the starting is the battery. I know it will start fine with the point stype distributer put back in, but that maybe something to look at. It happened to me with an Optima battery i got from work. Didnt like to crank, it would for a second then stall, then about 2 seconds later it would crank when i kept the key turned towards the starter.

The distributer may be a tooth out. Kind of odd. i had that trouble. And it bothered me so much. I would pull the HEI out and set the engine to TDC, then install the dist and set your plug wires. I had to do this a couple of times. I had a computer controlled HEI on my motor, i swapped in a non computer controlled HEI.

Check the module.

And it is OK to run without the advance hooked up, i did that for a long time before i got my advance spirngs kit installed. The adjustable vacuum advance may or may not help you. I tried it and then took the adjsutable advance off and have been fine without it. but i put the stock one back on.

 

Here is the write up Brom Rich. I talked to this guy on the phone bout the HEI adn boy is he knowledgable.


Making the odd-fire GM HEI run right on a 225

by Rich Motts,RRich



The GM HEI (High Energy Ignition) is one of the hottest ignition systems around. It produces higher than standard voltages with considerably faster rise times, a higher
current during the spark, as well as a longer burn time. It's far superior to standard ignition systems and most aftermarket ignitions. Many aftermarket ignitions make tall
claims, but very few live up to the standards created by the GM HEI.

The higher voltage means under the most severe loads the spark plug will get fired. The higher current of the spark provides a fatter spark, giving a larger surface area to
contact the air fuel mixture, insuring better ignition of the gasses. The faster rise time tends to blast through dirt and carbon, firing plugs when others can't (rivaling a rare
true CD system.) The long spark duration means the spark lasts much longer than usual, making it more likely to totally ignite the mixture.

STANDARD GM HEI Available Voltage 28-32 KV 45-50 KV Spark Duration .75 milliseconds 2.5 milliseconds Rise Time .2 milliseconds .05 milliseconds

Side benefits are it's a very reliable system, and parts are plentiful.

------ CAUTION - IT CAN KILL YOU! ------

It's so powerful it can stop your heart. As with any ignition system, always use caution when handling, and always use just one hand on the vehicle if it's running. You
don't want the shock running up one arm and down the other, passing through your heart on the way.

Mechanically installing the HEI distributor is really no trick, it just takes a little time. The trick is to get it right the first time, possibly saving hours of frustration.

The following is the procedure you should use before, during, and after the mechanical installation to help keep things in sequence.

Avoid aftermarket "enhancements" to the HEI, they either don't do anything or hurt performance.

How it Works

There's essentially several parts to the HEI system, grouped into two categories, Primary and Secondary.

The Primary system consists of the trigger mechanism, involving the Pole Piece (the rotating star shaped device on the distributor shaft,) the Stator Assembly (the ring
with the pointed tips surrounding the Pole Piece, the magnet directly under the Stator, and the Pick-up coil directly under and around the magnet.) This Stator Assembly is
a one piece unit. The Primary circuit also includes the ignition module itself, and one half of the ignition coil.

The secondary system involves the other half of the ignition coil, the rotor, and the carbon button between the coil and rotor, the distributor cap, the plug wires, and the
spark plugs themselves.

As the distributor shaft rotates, the pointed tips on the Pole Piece line up with the tips on the Stator (the stationary ring with pointed tips) momentarily. The strong magnet
under the Stator gets it's magnetic field disrupted slightly as the tips swing by. The integral pick-up coil wrapped around and under the magnet creates a pulse of electricity
due to the moving magnetic field. That electrical pulse is sent to the module via 2 small wires connected to the end of the module directly from the pick-up coil. The
module controls the ignition coil.

Until the pulse reaches the module, the module has been maintaining electrical current through the coil's Primary windings (low voltage side,) creating a very strong
magnetic field in the coil (lots of energy.) When the module detects the pulse from the pick-up coil, it "knows" it's time to make a spark. The module "shuts off" the
current through the coil.

Since there is no more supporting current in the ignition coil, the magnetic field collapses quickly. By induction, the magnetic field's movement creates a high voltage in
the Secondary windings of the coil. The coil has a little button on the bottom of it, replacing the old coil wire.

The button is in constant spring loaded contact with the center of the distributor rotor. The high voltage travels through the rotor, then jumps across the small gap at the
rotor tip to the cap's tower terminal. Then it travels down the plug wire to the plug where it jumps across the plug gap to ground. Hopefully it starts a fire inside the
combustion chamber at the right time.

You can see the Primary is where the spark is initiated, the Secondary merely directs it.

The Beauty, and Oddities of Odd Firing

The odd firing V6 is a unique little device. The firing pattern is not even, as the pistons do not come up in a regular even manner. The cylinder banks are at 90 degrees to
each other, but the crankshaft only has 3 journals (throws) for the connecting rods. This combination does not allow for the pistons to come up at regular intervals. The
result is the cylinders fire in an uneven sequence. Essentially they are grouped in 3 pairs of 2. One way to look at is fire, fire, pause, fire, fire, pause, fire, fire, pause. A
paired set of cylinders fire relatively close to one another time-wise, then there's a pause then the next pair fires. The pairs are #1&2, 3&4, and 5&6. To help understand
how it's firing let's look at the positions: #2 (right front), then #1 (left front) fire as a close pair. Notice both are at the front of the engine, are on opposite banks, and are on
opposite intake runners. #6 (right rear) fires, then closely thereafter #5 fires. Notice both are at the rear of the engine this time, on opposite banks, and on opposite intake
runners.

Then #4 and #3 fire closely, the center of the engine, but still on opposite banks and opposite intake runners.

If you think about it, it should vibrate like crazy like that, but it doesn't.

Several things take place. The lateral sideways vibration pulses generated by #2 is partially cancelled by #1's firing, thus cancelling most torsional (sideways) vibration.

The longitudinal (end for end) vibration pulses generated by the front pair firing (2 and 1) are cancelled by the rear pair firing (6 and 5). Whatever vibration is left is
dampened by the center ones firing next. It's certainly smoother than if you pulled 2 plug wires off a V8.

A heavy flywheel with a properly placed counterweight does most of the rest of the dampening needed. The final touch-up for vibration is handled by the front vibration
damper.

Mixture demands on the induction system are shared by both sides of the 2 barrel carburetor. Notice the odd fires use a single plane manifold, but the runners are kept
separated, rather than having just a big chamber.

The plenum chamber itself is small and has only a small opening between the sides for balance, allowing the air pulsations to be used effectively for atomization. The
runners themselves are fairly narrow, keeping the air/fuel mixture moving quickly for good atomization, especially at low speeds.

Notice the left half of the carburetor feeds the left half of the engine, and the right half takes care of the engine's right half. (Most other V configured engines "cross talk"
within the manifold as well, requiring a dual plane system.)

Notice that every other firing is on opposite heads, on opposite intake runners, on opposite carburetor venturis, and on opposite exhaust manifolds.

The close, then wide firing time of the firing sequence makes it almost like 2 different engines are running at once at different RPM's. The spacing between firing's of the
close ones act like it's faster than it really is, preventing stalling when most other engines would quit running. The great side benefit is the high torque it develops at slow
speeds, even at sub-idle speeds.

The combination of the odd cylinder firings and the induction system really make the little odd- firing V6's great for low RPM off-road use.

The little odd fire has accomplished many feats during it's career, including a few Bonneville Salt Flat World Speed records, and a short history of powering Indy cars.

Identifying Odd VS Even-Fire Distributors

Before installing or re-curving the HEI for the Jeepster, let's make sure you have the correct one. Odd and Even Fire distributors look similar, but operate differently. Use
the wrong one, it will run, but not like it should. 3 cylinders will be timed wrong.

The parts are interchangeable, and some rebuilders have mixed up the parts, so you can't go by the parts numbers alone, physically look!

Look at the inside of the distributor, it's easy to tell the difference. The Odd Fire has 3 points mounted on the shaft that rotate with the shaft - (called the Pole Piece, it
looks like a 3 pointed star.)

The Even fire has 6 points on the shaft, it looks like a 6 pointed star.

The Odd Fire has 6 unevenly spaced stationary tips (called the Stator) that point toward the inside, or Pole Piece.

The Even Fire has 6 points also, but are evenly spaced around the inside.

That's what determines when the module lets the coil fire. The coil will fire every time the Pole Piece tips line up with the Stator tips. You can see why they call Odd Fires
odd, they are.

Odd and Even caps are interchangeable, there is lots of confusion about which cap to use. When in doubt, look at a parts book for the right cap. Most of the ones I've seen
for odd fires have 4 posts in line, then a space, then 2 posts, then another space. They look like a V-8 cap with 2 missing towers. Don't let that deceive you, that is not how
it fires, 4 and 2. The inside of the cap has tangs that "steer" the terminals. I've also seen an odd fire cap with equally spaced terminals. Using an odd fire cap on an even
fire distributor does not make it an odd fire distributor, it just makes it a "nothing." It will run, but not like it should.

Before Installing the HEI.

Before removing the old distributor, mark on the manifold or splash panel where #1 terminal presently is on the cap. Use a crayon or chalk to make a good line that won't
smear off accidentally.

Remove the distributor cap.

Rotate the engine by hand until the rotor tip points toward where the #1 wire was on the cap (your mark.) Look at the timing marks, now rotate the crank slightly until the
mark on the vibration damper lines up with 10 degrees on the pointer. (You can rotate the engine by pulling on the belts, or put a socket over the center bolt on the
crankshaft in the middle of the pulley, or even on the alternator pulley nut.) The rotor should be almost dead on your mark unless you didn't have the timing set to about
10 degrees before we started. The damper should show about 10 degrees while the rotor tip is pointed to where the #1 wire used to be on the cap. You are now at TDC
(well, almost, you are at 10 BTC to make it easier.).

DON'T MOVE THE ENGINE POSITION UNTIL YOU ARE FINISHED WITH THE INSTALLATION

Remove distributor, note the position of the oil pump shaft down in the hole.

Install the HEI to the most convenient position where it can be adjusted so it can have the most swing. Make sure the rotor ends up pointing in the same direction as close
as possible to the old position, also make sure the pump shaft seats in the bottom of the distributor, you can tell if it's right if the lower housing sits down completely
against the timing cover. Look carefully, it's deceiving. If it's not right you can do damage, double check it. Use a long screwdriver to reposition the pump shaft if you need
to. Install the hold-down bolt finger tight.

Getting it to Run

You have to worry about 2 things when installing the HEI on an odd fire, "180 out" on the Secondary, and "out of sequence" on the Primary, either can mess you up. It's
not quite as simple as a normal even fire engine. By marking and adhering to the original #1 position we've virtually eliminated the "180 out" Secondary problem.

Swing the distributor housing to the center of it's possible travel.

Install cap and wires. Use the terminal directly over the rotor tip as #1, then wire it clockwise 6, 5, 4, 3, 2, same as before. If there isn't one directly over where the rotor is
sitting, select the closest. Find it by swinging the housing a little and find one that goes over the tip and still gives good room on the housing to adjust it.

Use 8mm HEI plug wires, the older 7mm wires' insulation won't handle the increased voltage. Use a dab of silicone dielectric compound on both ends of the wires. This
keeps the moisture out of the connections and keeps the boots from sticking on the terminals, making it easy next time you have to remove them.

Bypass the ignition resistor on the firewall. Disconnect both wires on the resistor. Turn the key on, find the one with 12 volts on it. Remove the other wire or cut it off and
wrap the end with tape to insulate it. From the 12 volt wire, run a heavy wire, at least 12 ga, to the "IGN" or "BATT" terminal on the HEI. This is the power input. (The
proper square spade terminals are available at most parts houses.)

If you have a tachometer capable of working on an electronic distributor, hook it to the "TACH" terminal on the HEI. Use the correct original plugs for your 225 or 231,
do not use plugs from anything else, the heat range will be wrong. Plugs are matched to the combustion chamber, not the distributor!

It's best to stick with standard AC's like it was originally designed for.

Gap the plugs a little wider, .040 is fine. A wider gap will give a better idle, too wide will kill top end performance.

Now, try it. It's either right and will start and run great, or the primary sequence will be off. You may have to play with the position of the housing to get it fired (timing.)
Simply have someone crank it while you swing the distributor housing back and forth slowly. If it doesn't fire right off put a timing light on it while cranking to make sure
it's close to 8 - 10 degrees. The timing light should work fine at cranking speed.

If the primary "sequence" is off (50/50 chance), it will probably run, but will have very little power. It may or may not backfire. It will seem like it's running on 3 cylinders,
'cause it is.

If that's the case, it's no problem. Simply move all the plug wires one tower over, either way, either clockwise or counter clockwise. What you are doing is changing the
synchronization between Primary and Secondary.

It should run on all 6 cylinders now, providing you didn't mix up the firing order.

But - you may have another little problem now. You may not be able to achieve proper initial timing because the distributor won't swing far enough without hitting
something. That's still not a problem. Determine which way you wish you could move the distributor. Now simply move all the wires around the cap 2 terminals in the
direction you need it to go. You have to move it 2 terminals at a time to keep it in "sequence." If you only moved it one you'd be back "out of sequence" again.

The best way to describe it is like a bunch of soldiers marching. Half the platoon was on their right foot, while the other half was on their left. Now we've got them all back
in sequence.

That's the beauty of odd-fire, it's odd.

Getting it to Run Right - Recurving for Mileage and Performance

Just installing an HEI is not all that needs to be done. You have to "dial it in" to make it work like it really can.

The stock HEI's vacuum advance diaphragm is far too sensitive to work with the older carburetor's ported spark vacuum system. It will advance to fast, too much, and too
soon, hurting performance, mileage, and possibly burning valves and pistons. Leave the vacuum line off till you make the modification.

You'll need to get an adjustable vacuum advance diaphragm from your parts store. It will run you about $20 or so, but it's well worth it. Parts stores will probably have to
order it, speed shops will probably have it in stock. Make sure it's for a GM HEI.

Before installing it, check the instructions to make sure, but all I've seen needs to have the Allen adjustment screw turned all the way counter clockwise to DECREASE
sensitivity. You do not want it to work fast, you want it at the least sensitive position.

Install it carefully as per instructions. If you have trouble reaching the mounting screws apply a little vacuum to the diaphragm, it turns the plate out of the way.

Install the limiter cam the new adjustable diaphragm came with. Set it so it only travels about 1/2 the way it did without it. You can make marks on the distributor body
before and after the cam is installed to see where to set it. 1/2 way should give you about 14 degrees vacuum advance. Without that limiter it will be worse than it was with
the original advance diaphragm.

Clean the damper and the pointer. It will help if it's painted black.

Roll the engine to TDC. Since you don't have timing marks beyond 10 degrees, you need to make some. We are going to make a $100 degree wheel for free.

Use dabs of white, yellow, or silver paint to make it easy to see against the black background. The tip of a small nail or wire makes a good brush..

Put a tiny dab of paint along the notch in the damper. This is your normal timing mark. Put another larger dab right on the 0 mark on the stationary pointer and a tiny one
on the 10 degree point.

When the notch and the 0 are lined up exactly, the timing is 0.

Rotate the engine till the scribed line lines up with the 10 on the stationary pointer. Put another dab on the damper exactly where it lines up with "0" on the pointer. Put a
"1" next to it. This is now another 10 degree mark.

Move the crankshaft another 10 degrees till your new "1" mark is opposite the "10" on the pointer. Now put another mark on the damper next to the "0" on the pointer.
Mark it with a "2" This is now your 20 degree mark.

Again, move the crankshaft 10 degrees more till the "2" mark is opposite the "10" on the pointer. Put another mark on the damper next to the "0" on the pointer. Marking
it "3". Right, that's your 30 degree mark.

Again, put the "3" opposite the "10" on pointer, mark the spot next to the pointer's "0" with "4" It should end up like this: 1 - 2 - 3 - 4 -
Be as accurate as you can.

What we did is made the degree marks on the damper rather than the pointer. The reason you heavily marked the 0 on the pointer is that now is your new reference. When
the "2" is opposite the 0, it's timed at 20 degrees. We can read all the way up to 40 degrees ("4") now, the original pointer only went to 10.

Disconnect the vacuum advance hose. Start it, take a reading - this is your "Initial Timing." It should be about 10 degrees.

Run it up to cruise speed, about 3000 RPM. Notice the marks moved as you revved it up. Now your "2" should be near the big "0" on the pointer. You can interpolate
what it is, like 23 etc.

The difference between the reading at speed and the Initial is how much your mechanical advance moved it. It should have moved it 10 to 15 degrees more than the initial.
So if you started at 10 degrees, it should have gone to 20 to 25 degrees. That advance is simply the weights inside the distributor, under the rotor. Kits are available to
modify this curve, but stock is better for off-road performance, since the odd-fire loves making low RPM torque.

Now reconnect the vacuum line to the advance. Take another reading at idle to make sure the vacuum isn't affecting it at idle, it should still be at the Initial reading. -- If it
moves the timing you have the wrong type of vacuum on the line. It needs ported vacuum, not manifold vacuum. Ported vacuum is near 0 at idle and gets stronger as you
accelerate till about 1/2 throttle, then it decreases again as the throttle open more. Manifold vacuum is strongest at idle. It's important you use the right vacuum source,
otherwise the system will work backwards!

Now rev it up to cruise speed again.

Take another reading. The difference between what you saw at cruise last time and now is how much the vacuum moved it. It should have moved another 10 or 15 degrees
again. So if the cruise reading before was 25, and now it's 35, the vacuum advance moved it 10.

That total reading should not exceed 35 degrees. More than that can and will create problems, like low mileage and overheating. Lots more can destroy things. What
happens is the plug ignites the fire long before the piston is at top dead center, creating undue cylinder pressures and possible damage. The term often used is "pinging,"
but you don't always hear pinging until it's too late.

If the vacuum advance is taking it too far, beyond 35, you can reset the little limiter cam inside the distributor that came with the adjustable vacuum advance to limit it a little
more. If it's much below 35, adjust it for more. Initial 8-10 Mechanical + ? (10-15) Vacuum + ? (10-15) Total = 35

That last little bit of detailing can make a world of difference.
.

If the mechanical advance weights are moving it too much, first check to make sure the part of the stop isn't missing. Use a small mirror to look under the weights and
their platform. You'll see a little pin hanging down inside a slot. The pin and slot are actually the stop that limits the travel. The metal pin has a little rubber bushing around
it, or should have. Over time the rubber bushing rots and falls off.

Get a curve kit at a parts store, about $5.00. It will have a new brass bushing for the stop pin. Pry off the old rubber (if it's still there) and press it on over the pin. Use
pliers to squeeze it on. Make sure it goes on all the way.

Measure it again, you should have a little less mechanical advance now. If you still have too much, take the springs off the weights. Play with the weights swinging them in
and out to get a feel for how they work. Mark on the housing how much they move the shaft, for comparison later. Try the different sets of weights in the kit to find one
that limits the travel more. The weights themselves change the starting point, or collapsed position of the travel, the stop limits the fully extended travel.

You do not need to use matched weights or matched springs, any combination that gives you what you want is acceptable. Sometimes I've had to weld a tiny drop or bead
of material on a weight to get exactly what I wanted. Sometimes grinding a little does it. Usually it's best to stick with the stock springs and weights if possible for what we
are doing. The lighter springs will give the mechanical too fast a curve for off-roading. Heavy springs with light weights aren't always the answer either. Sometimes they
won't advance far enough.

The time it takes to "dial it in" is well worth it. It greatly affects both mileage and performance, and limiting the total advance will keep the engine from destroying itself, or
at least shortening it's life.

Tips and Maintenance

Two kinds of grease is used with the HEI system. You'll find a thin layer of grease under the module - don't wipe it off! It's not ordinary grease, it's heat sink compound,
heat conducting grease. Available at any parts house. Make sure it's heat conducting and meant for modules. It's needed to conduct the high heat generated in the module
into the aluminum housing. Without the grease the module will burn out in a few minutes.

The other type of grease is Dielectric compound. It's a good insulator and moisture barrier. Use a dab on all the secondary boots, at the plugs and the cap terminals. It also
keeps them from sticking so next time they come off without breaking. Available at your local parts house too.

Beware of some grease sold that say they are good for both insulating and heat conducting. There are lots of products made to sell, but really don't do the job properly. A
good insulating grease is not a good heat conductor - think about it.

If you have to use a spacer on the fan to gain a little clearance, don't move the fan any closer than 1" to the radiator.

Carry a spare rotor and module off road, the weakest links in the HEI system. It wouldn't hurt to have a spare coil either. When a coil starts to break down, you will see
little whitish/bluish marks on the ends of the coil. If you see this, replace it before you end up walking. The same white/blue marks on plug wires is a tip off they are
leaking too.

Be careful when jumping batteries or making sparks. If you create a big spark anywhere in the system, even the taillights, it could blow the module if the key was in the
"on" position, running or not. When jump-starting someone, leave the key off while you hook it up and he starts. I've seen guys blow the module hooking up trailer lights.
The spark has a high frequency component that kills the module.