Engine Start Up Box Fabrication Help Needed

[John L.]

As I mentioned in a previous posting my 54 engine is freshly rebuilt and in the frame waiting for the first start up. I am at a point of fabricating a simple engine start up box. Tim Ehlers was helpful in providing me a schematic and article on building a box that he used on a 1966 as I recall. I have modified the original schematic provided taking out the electronic tachometer that was shown on the original schematic and have attached the revision below.

I am planning on utilizing a 12 volt coil and 12v battery (generator will not be hooked up in any way) on this start up so I would assume (a dangerous thing at times I know) that I need to have the ballast resistor in place as shown on the diagram correct? If so I was wondering what ohm rating I should be asking for when going to NAPA for one of these. This is a short term use only for this start up so I do not need something judging correct of course.

Admittedly I am not totally comfortable and well versed so to say in this so I need to ask about the wire gauge I should be using as well. Should I use a 12gauge wire throughout or is a thinner gauge required in some of the circuits?

Really basic stuff perhaps but I am just trying to cover the bases and would appreciate any helpful advice.
Thanks,
John


corvette box 3.jpg

[Gordon W.]

Re: Engine Start Up Box Fabrication Help Needed

Nobody replied so I'll chime in.

I built a wiring harness for my dad's 64 when we were starting it on the chassis. I didn't actually go to the effort of making a box but I like the idea of doing that and mounting gauges. Anyways, I used a typical 0.8 Ohm off-the-shelf ballast resistor and a stock coil. We also had no alternator hook-up (or generator in your case).

I wired the whole thing in 12g wire because I had a bunch of scrap wire laying around I could use.

Good luck.

[Tim E.]

Re: Engine Start Up Box Fabrication Help Needed

John -

Based on some quick research, the ballast resistor rating between 1956 and 1964 was 0.3-0.6 ohms and from 1965 on was 1.6-1.8 ohms. I also saw where the Paragon resistors measured 1.8-2.2 ohms.

The purpose of the resistor is to reduce the voltage through the contact points which eliminates possible burning caused by a full 12 volts over time. The coil still receives a full 12 volts when the key is in the Start position and then drops back to 7 or 8 volts in the Run position.

So...if you shop for a resistor, 1.0 - 2.2 ohms would be good. For your purposes, you won't be running the engine for hours or days so you probably don't need to lower the voltage by using a ballast resistor and could leave it out. The points may burn (which means metal migrates from one contact point to the other) over time but that's going to be quite a bit of time.

Tim

[Tim E.]

Re: Engine Start Up Box Fabrication Help Needed

....oh, I almost forgot! Your idea to use 12v for startup is a good one and 12 ga wire is plenty sufficient. In the ignition system, you won't be pulling any more current than 12 ga can handle. I converted my old 8N tractor to use 12v and the difference in cranking speed is amazing.

[John L.]

Re: Engine Start Up Box Fabrication Help Needed

Thanks for the ideas gentlemen....since I am only utilizing this set up for the initial start up and 1/2 hour or so run in I think I will not install the resistor.
Thanks,
John