Startup Break-in Wiring

[Sparkman86]

Getting ready to crank up a rebuilt 1974 engine in a 1970 model FJ40. I've got wiring harness completed but want to start up with minimal electronic peripherals while I run the engine for the first time. Doing this mainly because electronics components are not yet complete and I want to minimize variables in the system in case I need to troubleshoot. Does this logic make sense?

If so, does this wiring harness path make sense to run essential engine systems? Essentially just plugging in these wires and leaving everything else disconnected from fuse panel.

 

[Jdc1]

How long till you’ll be wrapped?

 

[Sparkman86]

If you mean wiring harness wrapped, that is done now. I've got the front harness fully run in the truck and the highlighted wires above connected and continuity tested already. From what I can tell, I should be able to start and run as soon as I have a battery for it. I just wanted a second set of eyes, so to speak, to make sure I wasn't overlooking something that would cause a problem.

 

[Jdc1]

If you mean wiring harness wrapped, that is done now. I've got the front harness fully run in the truck and the highlighted wires above connected and continuity tested already. From what I can tell, I should be able to start and run as soon as I have a battery for it. I just wanted a second set of eyes, so to speak, to make sure I wasn't overlooking something that would cause a problem.

I meant done with the build. Seems like the long way around to halfway install the harness.

 

[Sparkman86]

Still some months away.

Meh, yes and no. Not really any extra work or longer way around. Just delaying when I make connections for "non-essential" electronics. I've never seen this truck run and have no idea the "running status" of all its parts. My thinking is that I risk blowing up fewer things by not connecting them, in the event I have a major electrical problem that I'm not yet aware.

I still have some rebuild and testing to do on fuel sender, light switches, turn signal relays, etc. I'm itching to start this up after 8 years of ownership and think I'm ready to do that now instead of some time next year when I finally get everything else working.

 

[charliemeyer007]

I think you are working too hard. I bought my current engine after seeing/hearing it run sitting on the ground. Had a coffee can of gas and a battery hooked up. Arc the solenoid presto it ran.

Pull all the fuses except ign.

 

[Sparkman86]

I think you are working too hard. I bought my current engine after seeing/hearing it run sitting on the ground. Had a coffee can of gas and a battery hooked up. Arc the solenoid presto it ran.

Pull all the fuses except ign.

This is what I'm here for. This is my first ever car build and I'm figuring it out as I go, but I don't see any reason I can't run it the way I have it hooked up right now like in the diagram I posted above. Just want to make sure I'll be able to start it and get up to engine temp for the recommended break-in steps so I dont blow up my new engine.

 

[zerotreedelta]

All you really need is 12v to the coil (yellow) and bump 12v to the starter solenoid (magenta) to crank it. Pull the coil wire and it'll shut down.

Add a mechanical oil pressure gauge for now and Bob's your uncle.

 

[charliemeyer007]

Big fan of a direct read oil pressure gauge. I made a bracket to clamp to the lighted meter to the steering wheel housing. I used a piece of fuel hose to contain the nylon oil pressure hose from the back of the meter to the engine side of the fire wall; that way if the nylon hose breaks/leaks I don't get a face full of hot oil. I do have a small handy fire extinguisher if needed. Gauge/line still there since 1985 or so,

 

[Vossie]

Getting ready to crank up a rebuilt 1974 engine in a 1970 model FJ40. I've got wiring harness completed but want to start up with minimal electronic peripherals while I run the engine for the first time. Doing this mainly because electronics components are not yet complete and I want to minimize variables in the system in case I need to troubleshoot. Does this logic make sense?

If so, does this wiring harness path make sense to run essential engine systems? Essentially just plugging in these wires and leaving everything else disconnected from fuse panel.View attachment 3978079

ja, that will work. Just leave the rest unplugged.

but as said above, all it really needs is 12v to the coil and the starter and she will run.

 

[Living in the Past]

74 late F155 has an ignitor. Once started the coil circuit has a resistor in the circuit to reduce the spark while running. Also want to feed 12 bolts to the idle solenoid in the carburetor. If planning let run a while would also want to check temperature as well as oil pressure.

 

[Sparkman86]

74 late F155 has an ignitor. Once started the coil circuit has a resistor in the circuit to reduce the spark while running. Also want to feed 12 bolts to the idle solenoid in the carburetor. If planning let run a while would also want to check temperature as well as oil pressure.

I have the 74 motor but no igniter and an internally resisted coil. Do I need to run electrical with external resistor and bypass from coil + to starter or am I good to run wiring like 1970 spec without the ignitor?

Distributor is a 1972-74 60066 model with vac retard (but capped with no line to vacuum). I also have a 1969ish 60061 vac advance model that I could run.

 

[Sparkman86]

Big fan of a direct read oil pressure gauge. I made a bracket to clamp to the lighted meter to the steering wheel housing. I used a piece of fuel hose to contain the nylon oil pressure hose from the back of the meter to the engine side of the fire wall; that way if the nylon hose breaks/leaks I don't get a face full of hot oil. I do have a small handy fire extinguisher if needed. Gauge/line still there since 1985 or so,

Does this replace your electronic sender and gauge or is there a way to run both? I bench tested the gauge in the cluster and purchased new pressure sensor for the block so in theory, I should get a good pressure reading. Having both (at least during startup if nothing else) would be reassuring though.

 

[zerotreedelta]

If you want both, you'd need to pick up a tee fitting - pretty readily available, and it lets you run the OEM sender and a gauge on the one port.

 

[charliemeyer007]

I just run the direct read. The OE gauge has never worked correctly despite at least 2 new senders. You could put a "T" in the line and run both if you wanted.

 

[Living in the Past]

I have the 74 motor but no igniter and an internally resisted coil. Do I need to run electrical with external resistor and bypass from coil + to starter or am I good to run wiring like 1970 spec without the ignitor?

The purpose of the resistor is help with wear on the spark plugs. By passed the resistor for a hotter spark starting a cold engine starts. Coil with resistor is used so the coil has a path to discharge in the gap in the distributor between rotor and plug wires in the cap. Something completely different.

 

[pb4ugo]

Typically a points style ignition using coil with an internal resistor needs 12 volts to the positive side of the coil. A coil without an internal resistor needs a resistor b4 the connection to the positive side of the coil. The resistors reduce the voltage on the negative side coil going to the points and makes the points last longer.

 

[Sparkman86]

Typically a points style ignition using coil with an internal resistor needs 12 volts to the positive side of the coil. A coil without an internal resistor needs a resistor b4 the connection to the positive side of the coil. The resistors reduce the voltage on the negative side coil going to the points and makes the points last longer.

Sounds like I'm good to run my internal resistor coil with no ignitor, just like the 1970 would have run.