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Discussion Starter · #1 ·
I've read that you can run a toggle switch to the 12 volt source going into a hei distributer and since it will only turn over without firing it turns over easier and faster , and then you flip the toggle and it starts. Has anyone had any experience with this . It's a 355 with maybe 450 HP.
 

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Yes that is done a lot with big cams, high compression and lots of initial advance. This gives the starter a running chance to turn the motor over before fighting pressures building from early ignition timing.

Use a safety covered switch so just batting at it shuts it off since the key switch no longer has control of on/off if you wire around the key switch. The other way is to wire in series after the key switch so when the key is turned off so is the ignition whether the toggle is on or not. This problem is the better way because if the toggle keeps power on the ignition and the engine is not taching over the module will loose its smoke and stop operating all together. My daily driver is wired in the former way and I forgot while being interrupted while running a static test that the ignition was on. When I cam back it was to a dead module. Fortunately as with those days of yesteryear when I carried a spare set of points I carry a spare module for the kind of occasion the module dies. As a spare it doesn’t need to be an expensive MSD, just something to limp home on.

Bogie
 

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I've read that you can run a toggle switch to the 12 volt source going into a hei distributer and since it will only turn over without firing it turns over easier and faster , and then you flip the toggle and it starts. Has anyone had any experience with this . It's a 355 with maybe 450 HP.
I've used this as a kill switch, for you it would serve a dual purpose and it is cheap.
 

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I have ran a toggle switch for over ten plus years on my truck as I used to use a keyed source but when I bought the truck the person who owned it before me hacked the wires off and did not do a good job and left things a mess. I kept having wires quitting on me so I run straight from the battery with an inline fuse then to the distributor.

Bogie already said already the con of doing it that way and leaving it on and it not running and it can burn the module but I have been lucky to not forget it being left on etc. I just turn my engine over for a few seconds and flip the switch and bam its good to go. I am not running high compression or really over advanced timing at idle but I use a good gear drive starter and a battery with more power then what my engine needs and it turns over really easy.
 

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Is it as simple as just using a switch on the 12 volt source to the distributor.
Yes the simple way is to find the key switched B+ power to the distributor. Cut into it and splice a wire back to a switch you install on the instrument panel then wire back to the distributor side of the lead you cut. You probably should have a schematic wire diagram for the vehicle so it’s easier to ID this wire. Plus some older vehicles have wiring in place from the points days when there was a B+ hot line from the starter relay left over from the good old days when the distributor got 12 volts while cranking and 6 through a resistor or s resistive wire while running. So this is stuff you need to check out. A toggle in the run wire would not be effective if the ignition has a starter switched circuit as well. So you can expect this on older pre 1974 vehicles that are modified to electronic ignition and some in the 72-80 time frame where the factory hadn’t completely cleaned up the wiring from the points to HEI ignition yet. So if there is a sneak circuit from the stater solenoid putting a switch in the B+ run circuit off the key wouldn’t solve your problem. So you need the schematic to trace this out to be sure you have control of the power to the distributor.

This gives primary control with the ignition switch so if you forget to turn off the toggle when you shut down there will be no power on the module which will burn out if powered and the engine is not running. Wired like this the worst that will happen is if the toggle is left on when you crank up with the key switch it will be hard to crank as it is now, when you recognize that you just cycle the toggle to off till the starter has the engine spinning easier then turn on the ignition.

Bogie
 

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Discussion Starter · #9 ·
a thought, can I wire off any 12 volt wire that is only on with the ignition and then run that wire threw the toggle switch that then goes to the distributor. There are many12 volt wires that are only on when the ignition is on , that are under the hood, I have two that I'm using now . Or am I missing something. So if I leave the toggle switch on it won't burn out the Ignition module. Thank you for your answer.
 

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It would be very helpful to know what this vehicle is, assuming it’s a factory build with a factory wiring system in it or if it is something modified?

Bogie
Agreed. This sounds like we're band-aid fixing a super simple problem. I have built blown 540s in excess of 1000 hp and they don't need a kill switch for the dizzy.

Find out what's wrong and correct it instead of finding spackle to cover it up.
 

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Discussion Starter · #12 ·
It would be very helpful to know what this vehicle is, assuming it’s a factory build with a factory wiring system in it or if it is something modified?

Bogie
a thought, can I wire off any 12 volt wire that is only on with the ignition and then run that wire threw the toggle switch that then goes to the distributor. There are many12 volt wires that are only on when the ignition is on , that are under the hood, I have two that I'm using now . Or am I missing something. So if I leave the toggle switch on it won't burn out the Ignition module. Thank you for your answer.
It's a built 350 SBC set up and built for nitrous, running in a 87 Camaro. I pulled the computer it is running a 750cfm Holley double pumper. There still is wiring that are not being used that are 12 volt when the ignition is turned on. Running 36 deg total timing which is about 20deg initial. It works like hell turning over. If you need the total built I have it typed up here someplace. TRying to save my starter.
 

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20 degrees of base timing is a lot. Knowing the cam and compression would be helpful so the critical elements of the build are important pieces of info.

A test you can perform is cranking with no spark to the plugs simply by pulling the plug wires and grounding them. This will separate whether this is an excess compression issue or insufficient cranking power of the motor from excess pressures of early ignition.

Insufficient starter motor power can be anything from a weak battery its wiring connections to poor engine grounding as much as a dying starter motor or bad contractors inside the solenoid.

You really need to sort out and eliminate unneeded wiring with the computer and injection gone, the chances of shorts and failures inside those wire bundles is really high so your way better off to get unneeded wiring out of there. It will also clean the look up a lot.

How are you handling the fuel supply to the engine the original EFI system uses a lot of pressure that a carb cannot handle.

Also where are you getting power for the HEI, these use a simple connector into the cap, to switch power only requires cutting the B+ wire and installing a toggle switch that lets you control power between that applied to the ignition key switch and the HEI. Yes you could use any switched 12 volts that is on during cranking and run, but why create a different circuit.

If you don't have a wire diagram for this vehicle you need to get one cleaning up the wiring when you remove the EFI and computer is a huge part of the job.

Bogie
 

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Not knowing your compression ratio and vacuum at idle I would try this. Reduce the initial timing to about 10-12 degrees and hook up the vacuum advance to manifold vacuum. You have now 16 degrees of mechanical (36-20). Increase the mechanical to 24 with an initial of 12 will give you the 36. Adjust the mechanical advance rate to start above your idle speed and come in quicker to make up for the loss of the 20 degrees that you took out.
Manifold vacuum will increase the spark back to the 20 plus to get your idle which I assume is optimum at 20 degrees. You will probably have to get an adjustable vacuum advance can to fine tune. Manifold vacuum is your friend.

This is of course your battery, starter and wires are in good shape as Bogie said. I agree with Bogie 20 degrees initial mechanical seems high for a street engine.
 

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Discussion Starter · #16 ·
20 degrees of base timing is a lot. Knowing the cam and compression would be helpful so the critical elements of the build are important pieces of info.

A test you can perform is cranking with no spark to the plugs simply by pulling the plug wires and grounding them. This will separate whether this is an excess compression issue or insufficient cranking power of the motor from excess pressures of early ignition.

Insufficient starter motor power can be anything from a weak battery its wiring connections to poor engine grounding as much as a dying starter motor or bad contractors inside the solenoid.

You really need to sort out and eliminate unneeded wiring with the computer and injection gone, the chances of shorts and failures inside those wire bundles is really high so your way better off to get unneeded wiring out of there. It will also clean the look up a lot.

How are you handling the fuel supply to the engine the original EFI system uses a lot of pressure that a carb cannot handle.

Also where are you getting power for the HEI, these use a simple connector into the cap, to switch power only requires cutting the B+ wire and installing a toggle switch that lets you control power between that applied to the ignition key switch and the HEI. Yes you could use any switched 12 volts that is on during cranking and run, but why create a different circuit.

If you don't have a wire diagram for this vehicle you need to get one cleaning up the wiring when you remove the EFI and computer is a huge part of the job.

Bogie
Great tips thanks, It runs best a 36 total without Nitrous and the mechanical advance is tight on the distributor. 15Deg. It has adjustable vacuum. For fuel I run a mechanical pump from the tank and a Big electric pump to a small fuel cell that has 105 octane for the nitrous. I hate looking at the wires but I know I;ll even hate them more digging through them to get rid of them.

The spark wire disconnect test is something I didn't think of or know about , I'll do that first thing.

Its a 301 duration linati nitrous cam with 580 lift, That's all the information I have on the cam. 10.5 to 1 compression/
 

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Discussion Starter · #17 ·
Not knowing your compression ratio and vacuum at idle I would try this. Reduce the initial timing to about 10-12 degrees and hook up the vacuum advance to manifold vacuum. You have now 16 degrees of mechanical (36-20). Increase the mechanical to 24 with an initial of 12 will give you the 36. Adjust the mechanical advance rate to start above your idle speed and come in quicker to make up for the loss of the 20 degrees that you took out.
Manifold vacuum will increase the spark back to the 20 plus to get your idle which I assume is optimum at 20 degrees. You will probably have to get an adjustable vacuum advance can to fine tune. Manifold vacuum is your friend.

This is of course your battery, starter and wires are in good shape as Bogie said. I agree with Bogie 20 degrees initial mechanical seems high for a street engine.
The 20 deg initial is what it is to get the 35 deg total because of the tight mechanical range on the distributor.. So your saying buy a advance curve kit for the distributor is that what you are conveying.
 

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An advance curve kit will adjust the curve of the mechanical advance. To get to more mechanical advance you have to increase the range of the mechanical advance. Not knowing what distributor you have I can not tell you how to do this. GM distributors have a bushing riding in in the baseplate slot. This needs to be removed or made smaller. If this has been modified by others it may have been welded to reduce the slot. Aftermarket distributors have the same principal. The advance kits usually have the bushings of different sizes.

This is a trial and error situation. You can do this by measuring the angle of the movement on the bench with a protractor. Distributor will have to be removed. Just remember the distributor turns half the degrees of the crank. 12 degrees of the distributor advance will be 24 degrees of the crank. Google this as there are many youtube videos on this. It is hard to explain exactly without pictures and a tutorial.
 

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Discussion Starter · #19 ·
I want to thank the people who take the time to advice and use their obtained knowledge to share with others. Questions in forums are often received by insults and disregard. So it can be hard to get advice that can be trusted, so thank you.
 

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Stock Starter?
First thing I'd do is get rid of the factory wiring from the battery to the starter and replace it with 00 gauge stranded welding wire and cable ends soldered on. No crimped, soldered.
Then I'd find all the engine grounds including the starter to block interface and sand those shiny and see where you are.
Stock starters are usually good for stock engines. Sometimes you need a little more. Not all of those after market mini starters are worth a crap either so watch for that. In a 3rd, you have a 53tooth starter ring gear so you loose a little mechanical advantage right there but you can't fit a 168 under the stock bell either.
One more thought, No need to pull plug wires. Just unhook the dist wire. It's far easier and you don't even have to do that. If it cranks well cold, you don't have an advanced timing problem. It's more likely a starter heat problem because of the exhaust running so close to the starter in those cars.
 
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