The Stovebolt Site Forums The Shop Area Engine Shop New HEI in 235 - Fires But Won't Run

I installed a Langdon HEI on my 1959 Apache 235 engine this weekend. I believe I followed all the instructions correctly (not sure how to try to get to 10 degrees before tdc so I just left the pointer on the BB on the flywheel - on the compression stroke of the #1 cylinder). When I try to crank the engine it does fire off but then dies immediately, nearly before I can get my foot off the starter pedal. Any ideas or troubleshooting tips? What other information can I provide that might help someone out there think of something I can try? Thanks in advance.

You are likely using the resister bypass wire. The only time it sees power is when the starter switch is turned on. As soon as you release the starter, the power stops. You need the wire that has constant 12v when the ignition switch is in the run position.

Thanks Truckrolet. According to the wiring diagram in the shop manual, there are two 20 gage green wires coming from the same terminal on the ignition switch. One goes to the coil and the other to a resistor mounted on the firewall in the engine compartment (from what I can tell from the diagram). I disconnected the wire from the resistor, and I cut the two green wires at the ignition switch and tied them together to a 10 gage wire run separately now to the coil (well, and I also later installed a relay to get power straight from the battery, fused, with the 10 ga wire just sending the signal to the relay - exact same results either way).

Have you checked to make sure that the wire to the + side of the coil has 12 volts when switched on?

It sounds like what has already been said that it is only getting power while cranking.

No, didn't try that but I certainly will now. Thanks!

Just for your information, While cranking a engine, full battery power is supplied to the coil from the starter solenoid. This insures maximum voltage during cold heavy cranking. Once the engine starts and the key returned to run, voltage from the switch is routed through a resistor, (could be firewall mounted or built in wire). The resistor knocks the voltage down to 8 or 9 in a 12 volt system. The engineers designed it to run at this lower voltage for longevity and parts wear.

When HEI came along, it needed full voltage all the time so the resistor circuit was removed and the key switches revamped. The starter no longer supplies voltage during start, the key switch does. The late model key switch has a start and run contact tied together and one 12 gauge wire to the HEI.

You can make yours work by still using the starter solenoid wire and key switch. There is no need for a relay, although its a good idea. It sounds like is your relay is dropping in the run position.

A simple test light will prove out the key switch, just find voltage in run position and use it to trigger your relay. For start, use the factory wire all ready run to the coil and tie it to the new HEI wire or back at the relay. It may skip a beat when the relay jumps from start to run, but the engine should keep running. I would through a spare relay in the glove box, just in case!

Joe

Thanks Joe. I haven't been able to get back to the truck yet, but my current plan is to test the voltage at the coil in the run position. Based on the troubleshooting section in the shop manual and earlier comments above it seems like the problem is most likely exactly as suggested - voltage is cutting out after I take my foot off the starter pedal (the ignition switch is either off or on - no start position vs run position.)

Assuming I confirm the above with testing, I plan to put all the original wiring back to factory routing, "except" I will take the wire that ran to the coil and run it to the relay instead, and run the 10 gage 12v output from the relay to the coil - which is exactly what you are suggesting above if I read you right.

I'll fill you guys in after I get a chance to work on the truck again next weekend.

Thanks!

On my '56 I ran a jumper wire from ign 2 to ign1 on the switch.

I had the opposite problem. I had no ignition in start. And the truck was hard to start for years before I figured it out. It would finally start when I let the switch go back to on after several failures. Now it fires right up like it's supposed to.

I think he is still using the foot starter, so once his ignition switch is on, it should give power regardless of what the starter is doing. If he were using an ignition switch with the start position and a solenoid starter then what happened to you could easily happen to him.

So long as his ignition wire to the + side of the coil does not have the resistor in the line he should be good to go.

Yes I realize he is using a foot operated switch. I was just using my example to point out there are two circuits there.

The terminal on the side of the foot switch goes to the ignition switch on a '59. This prevented the truck from starting if the foot button was depressed with the key off. The juice goes in the switch then out through a separate terminal from the one that went to the ballast resister. In his case the one from the starter terminal seems to be the only wire he has going to the HEI.

Now that I think about it, jumpering to the other terminal isn't going to help him. He needs to find the terminal in the key switch that is ignition in the on position and use it to the HEI. He can remove the wire from the side of the foot switch.

Yep.

And by using a relay, his original wires should work, even the resistor wire. It would need to be checked, but the relay should pull in with the voltage drop of the resistor wire. If it does, the relay could pull power right off the battery with heavy wire. It might be a quick way around the key and foot start situation.

Joe

If his had the ballast resistor like my 58 had, the wire from the ignition switch to the resistor is just like any other wire of it's size. The resistor wires came in a little later I think. So you're right, it should work the relay just fine.

I used the original ignition wire to turn on the main relay when I installed a fuel injected 350 in my pickup. Made life a lot simpler just to have a relay carry the load instead of worrying over the original wiring.

I finally got around to working on the truck again last weekend. I reconnected the original wiring back to the factory configuration - wiring at the ignition switch, resistor, etc. - except that I installed a relay on the firewall by the battery and connected the wire which originally ran from the ignition switch to the coil to the relay. I then ran 12V from the battery to the coil, through the relay. It cranked on the first try, with no effort at all. No choke, no stomping the gas pedal to prime, etc. I drove it around the parking lot and it seemed to run pretty nicely. I do have a question about how to set the timing correctly (to the 10-18 degrees btdc that Langdon recommends), but I'll write a separate post to the forum about that. Thanks for all the input and help!

Dan, glad that worked out. The relay is a good solution for future change overs.

As for timing, just advance it till you hear pinging when lugging the motor, then back it off till it quits. A few test drives will be required.

JOe