Stock Ignition Switch and HEI

[engineer_gregh]

In the interest of not high jacking someone else's thread I started a new one. Interesting comment on HEI and stock ignition switch, "stock ignition switch will not handle the HEI". Recommendation is to add a HD relay and run power directly from the battery to the HEI. It makes sense to me and I've noticed that hot starts can be a problem. Anyone done this and want to walk us through how they accomplished it?

[Brave71]

I just installed an AAW wire kit in my truck , they supplied the ignition switch,set up for HEI...do you think I need to contact them ? I don't want any problems! I have not started the truck yet, thanks for the heads up

[LockDoc]

Originally Posted by engineer_gregh

In the interest of not high jacking someone else's thread I started a new one. Interesting comment on HEI and stock ignition switch, "stock ignition switch will not handle the HEI". Recommendation is to add a HD relay and run power directly from the battery to the HEI. It makes sense to me and I've noticed that hot starts can be a problem. Anyone done this and want to walk us through how they accomplished it?

The only thing I can tell you is that I have always run my HEI's off of the "Ignition Unfused" terminal on the fuse block and have had no problems. (At least 6 converted vehicles) In fact I had my '69 Suburban at the alignment shop yesterday and the owner couldn't believe how quick it started when you hit the key. If someone is having problems with hard starting they have a bad connection, timing problems, boiling fuel in the float bowl, or "heat soak"... not the ignition switch. I'm not saying you can't have a bad ignition switch, and the HEI may aggravate it if you do, but the HEI won't make it go bad...

Just my 2¢ worth.

LockDoc

[engineer_gregh]

I ran my HEI power the same way Leon. I've added the thermal spacer under my Edelbrock carb, use an Edelbrock fuel pump and plumbing from the pump to carb. I've also added a 100 amp alternator as the original couldn't keep up with the dual electric fans and other accessories. Sometimes when the weather is hot I feel like I have to wind the starter more than I should to restart the engine hot. Other times it starts as soon as I hit the key. I'm not sure if its electrical, fuel pressure, or an ethanol problem. Where should the timing be for a rebuilt 402 BB with 268H cam?

[LockDoc]

Originally Posted by engineer_gregh

I ran my HEI power the same way Leon. I've added the thermal spacer under my Edelbrock carb, use an Edelbrock fuel pump and plumbing from the pump to carb. I've also added a 100 amp alternator as the original couldn't keep up with the dual electric fans and other accessories. Sometimes when the weather is hot I feel like I have to wind the starter more than I should to restart the engine hot. Other times it starts as soon as I hit the key. I'm not sure if its electrical, fuel pressure, or an ethanol problem. Where should the timing be for a rebuilt 402 BB with 268H cam?

I am betting it is a fuel related problem. One way to tell if it is electrical is to make up a jumper wire with the HEI connector on one end and an alligator clip on the other. When it does it unplug the BATT wire on the HEI and connect your jumper wire from the HEI to the + post on the battery and see if it starts... You will have to unhook the jumper wire from the battery to stop the engine when you do that.

I really can't tell you on the timing because I set the timing by ear on my older vehicles. I learned to do that because I have bought many vehicles over the years that had modified engines and the PO didn't always know what modifications had been done.

LockDoc

[Fitz]

Originally Posted by Brave71

I just installed an AAW wire kit in my truck , they supplied the ignition switch,set up for HEI...do you think I need to contact them ? I don't want any problems! I have not started the truck yet, thanks for the heads up

This is a tempest in a teapot. The AAW switch is more than adequate for HEI. I've been running an AAW harness with a stock ignition switch since 2006 with no problems.

[engineer_gregh]

Jumper wire is a great idea. I'll give that a try in the next few weeks. Thanks for the suggestion.

[IHeartGroceries]

I would think a stock, or near stock low compression SBC wouldn't suffer any issues from running the HEI coil off of the OE ignition switch, as already stated.

Even so, running full power from the battery should be pretty simple...
Here's a write-up somebody did. Different application, but same principle.

http://www.hoigto.com/tech/powerHEI.htm

[LockDoc]

Originally Posted by engineer_gregh

Jumper wire is a great idea. I'll give that a try in the next few weeks. Thanks for the suggestion.

No problem. I edited both of my previous posts so be sure and read through them again...

LockDoc

[davepl]

Stick an ammeter in line. I believe the max current draw from HEI is around 5 amps. It was 3-4 with breaker points.

I do not think any non-defective ignition switch would have trouble with this. If it did, you would be able to feel heat back there, and I bet you can't.

[engineer_gregh]

I just checked voltage at the fuse block connection; A/C on high with headlights on ~13 volts at idle, no a/c or headlights on ~14 volts.