Wiring for a engine stand

[1965barr]

Hi just built an engine stand time to wire it , I think I got some of the wiring figured out but need some help to finish it ,have no problem reading a schematic but making one is different here is a few pics what I have . Thanks a lot gary

 

[Mattax]

Your blue wire (Ignition - run) needs to be connected to the power sources.
The coil power should be through the 1/2 ohm reisistor.

Relay - not sure what you're thinking about there. For the starter?

Momentary switch needs to send power directly to the coil brown wire, and connect the battery to the starter solenoid.

 

[1965barr]

Thanks Mattax ,the relay I was going to use for the cooling fan if needed ,also didn’t know if I needed the starter relay or just the on/off for all main power plus the push button to start the motor? These are spare parts I have to use. Picture should be easier to look at now haha to late for me last night.
What you said take blue up to on/ off switch and pos side does go though 5 ohm resistor but that goes where to ?

 

[67Dart273]

1...Power switch. I'd add about a 20A fuse to dump everything if something bad happens

2..Start relay.......Standard bosch relay wiring

Connect 30 to main battery power
Connect 87 with a large wire no 12 or 10 to the small starter solenoid terminal
85 gets grounded
86 goes to your starter button and then to battery power

Go over to MyMopar and find one of the simplified diagrams for a basis, here:

Fans/ other. I would find out what they draw, you might need a relay to operate them, and depending on how much, might need a circuit breaker or quite large fuse. Pay attention to toggle switch ratings and take them with a grain of salt. 120/240AC rated switches WILL NOT handle the same amperage at 12V unless rated. This has to do with the switching spark at DC which is different than AC.

 

[1965barr]

Ok 67Dart273 so I can use a Bosch relay instead of the mopar starter relay ,good I have more Bosch relays and yes definitely use a fuse and thanks for the wire sizes , that was my next two questions. The other side of the push button goes to power off the the switch is that correct? The switches I have are marked 20 amp / 12 volt Thanks gary

 

[67Dart273]

you can either wire the starter button "hot" to the battery or through the power/ ignition switch. You might want to be able to bump the starter with ignition off, like setting timing or adjusting valves.

Some comments on Bosch relays. Be careful of the coil wiring. This is because most of them have a built in spike diode, and if you wire the coil backwards you will blow up that diode

Also there exists a couple of variations on some "high current" ones. Some have 87 and 87A as one contact, and (that is normally open, there is no normally closed on those) and so the two terminals handle the extra current of the heavy duty contacts

Still others have LARGER pins to accomodate the larger contacts and those type will not fit a standard socket

Here's a good read EXCEPT that some of the diagrams reverse the coil grounding on 86/85 so be aware

https://www.electricalrebuilders.org/techlib/tech_articles/four_uses_for_relays.pdf

 

[1965barr]

So I think I have this correct so far but for the fan where would the fuse go and the rest of the wires for that and would you put any more fuses anywhere?
Also forgot at the ballast resistor for the brown wire where does that go to ?

 

[Mattax]

This is what's need to run the car.
The supply can be a junction as shown or joined in any of the connectors if that's more convenient.

This what is needed to start.
When the momentary push button is closed, power needs to go to the starter solenoid terminal and direct to the coil positive.
A 5 pin ECU will get power through the 1/2 ohm resistor.

You can use the starter relay but on a stand I cant think of a reason you ought to.

 

[Mattax]

Given a choice I'd put a ammeter in where the fuse is shown on your diagram.
See a problem, open the switch. Otherwisae a maxifuse or fusible link rather than a regular fast blow.
But I happen to have a couple of these kicking around.

 

[67Dart273]

So I think I have this correct so far but for the fan where would the fuse go and the rest of the wires for that and would you put any more fuses anywhere?
Also forgot at the ballast resistor for the brown wire where does that go to ?
View attachment 1715735199

View attachment 1715735200

You want 30 for the starter relay hooked direct to battery and not through power switch

Wire fan relay same as starter one, that is 30 direct to battery and a fuse/ breaker in the 30 line if desired (good idea)
Ground the coil 85
Run starter switch/ fan switch of the BATTERY not the ign switch. This is so you can bump engine with igntiion off and so you can run the fans for cool down after engine shut off

 

[1965barr]

Take two haha hope everything is correct so far , for the switch for fan ,battery to fuse to switch to relay 30 to 87 to fan , 85 is ground and ground off of fan is this correct. Gary almost there haha

 

[67Dart273]

No, not right. I thought you were going to use a relay in the starter solenoid circuit? But the important thing is the brown coil wire can NOT be connected that way. The original IGN2 "bypass" circuit is a separate "switch" or contact in the ignition switch so it is isolated. They way you have that, the starter solenoid will pull a drain on the coil power and "drag" it down

 

[Mattax]

How's that different than when people put the ignition switch in run, then jump the starter relay?
I'm not saying he has to, or ought to do it that way, but it should work.
No?
Assuming the start switch can handle the load.
lemme look at an FSM or the VAT40 manual for solenoid draw

edit> Not coming up with an amperage for the solenoid draw, although it does show the switch (I take to mean switch in the relay) to carry 15 amps at 6 Volts. if so, that's what feeds the solenoid.

 

[1965barr]

3rd take haha , thanks for hanging with me but I think I have the push button wrong it needs power to the one side and where I have ballast to one side needs to join up with 86 but could be wrong .

 

[Mattax]

Well you can use a relay if you want. On the car, using the starter relay makes a much more direct connection and saves the operator from having to press a seperate start button (pedal, whatever)

The relay won't care which side of the actuating circuit the momentary switch is on.
However in this case I'd not hook the ignition-start that way. Connect it to the terminal that is intended to carry a high load.
Connect the other side of the momentary switch to ground.
@67Dart273 or @crackedback may advise differently. See what they say.

Why is there a green jumper across the 5 ohm resistor?

 

[Mattax]

With the momentary switch like this, there is a continuous connection to ground through the starter solenoid.

The path to ground through the coil is interupted to release a high voltage charge to fire each spark plug.


In this one, the path to grpound is continuously interupted

Which means the current to the starter solenoid will get continously interupted as the relay flickers on and off...

 

[1965barr]

Hi Mattax the wiring harness I have from m&h has it crossing to use with a 4 pin ecm , yes have a few leftover gauges .the harness works with 4 or 5 pin

 

[Mattax]

FWIW. This is from a Delco-Remy catalog.
Similar to the Chrysler starter connections.
GM has their own terminology for some things. In this case "magnetic switch" is what they call an electromechanical relay. Others will call that style a "Ford type" although its also found on mopars in the very early 60s.

The relay is used when the push button is located some distance away from the starter.
This keeps wires connecting to the starter solenoid (Switch terminal and wires #1 and #2 in the drawing) short.