Low dollar distributor tester

[jeff74]

I came across an article about building your own distributor tester.. "Build your own distributor test machine for under $100" by Joe Randolph

Seems like a neat idea and I have everything on hand except for a pwm motor controller, which I ordered from ebay for about $15. The first picture is a test of the fan motor from my truck , using a cheap digital tach I had bought to use with my lathe, but haven't mounted yet. I just taped the magnet to the 'coupler'(piece of heater hose) to try it out. It's pretty steady right around 3000rpm

Second picture is a few other parts, a degree wheel that I printed and glued to a piece of thin cardboard , a toasted honda timing gear that will be the hub for the wheel, and an old oil pump shaft to drive the distributor. I had to open up the timing gear slightly on the lathe to be a nice fit on the bottom of the distributor gear.

I'll build the stand this week, for now it will just be 2x4's. I also have a coil and some old spark plug leads around here. The truck is mostly parked for the winter so it'll be cool to get the distributor all set up.

[jeff74]

I made the stand today. Still need to secure the motor and make a bracket to hold the tach pickup, and then there's the coil and power wiring. There's a metal plate at the top to ground everything to.

I gave the degree wheel a thin coat of epoxy on both sides and it's being held flat until it cures.

[Getter-Done]

Nice set up

The Mechanic that rented the shop from my Daddy,
He had a simple set up for HEI chevy distributor.

This brings back memories.

[jeff74]

Originally Posted by Getter-Done

Nice set up

The Mechanic that rented the shop from my Daddy,
He had a simple set up for HEI chevy distributor.

This brings back memories.

Right on. Thanks

Here's the rough set up today.. it works...
With a 1 ohm resistor in line the motor spins at about 600 rpm and the timing light is working. I'll have to wait for my motor controller to do more.

It doesn't seem happy with only one spark plug.. not sure where the other 7 sparks are going, but I can hear them, maybe I'll run the other wires to a common gap

[RustyPile]

Those other 7 sparks are just arcing within the cap somewhere. Won't be long until one of them finds something important. You don't need a distributor cap or rotor for testing.. Simply run the plug wire directly from the coil to a sparkplug. Also, where's the ballast resistor for the coil???

[Getter-Done]

Originally Posted by jeff74

Right on. Thanks

Here's the rough set up today.. it works...
With a 1 ohm resistor in line the motor spins at about 600 rpm and the timing light is working. I'll have to wait for my motor controller to do more.

It doesn't seem happy with only one spark plug.. not sure where the other 7 sparks are going, but I can hear them, maybe I'll run the other wires to a common gap

I will take a Picture of the bench that He had it set up on soon.

That is looking Great

[jeff74]

Originally Posted by RustyPile

Those other 7 sparks are just arcing within the cap somewhere. Won't be long until one of them finds something important. You don't need a distributor cap or rotor for testing.. Simply run the plug wire directly from the coil to a sparkplug. Also, where's the ballast resistor for the coil???

Thanks I'll try that. I didn't use a ballast resistor for that quick test.. I have lots of details to work on..

[Getter-Done]

You could make you a Spark plug holder.

[jeff74]

I tried running the timing light off the coil wire, but the numbers jump around because of the 8 sparks per rev. It would be usable that way, but instead I cut 7 short wires , brought them together to one wire and they jump a small gap to the metal plate.
No more arcing around in the cap, at least.

[RustyPile]

Originally Posted by jeff74

I tried running the timing light off the coil wire, but the numbers jump around because of the 8 sparks per rev. It would be usable that way, but instead I cut 7 short wires , brought them together to one wire and they jump a small gap to the metal plate.
No more arcing around in the cap, at least.

I don't know what "the numbers jump around" means??? What "numbers" are you talking about. Did you remove the cap and rotor and run the coil wire to a sparkplug.. Just powering the timing light from the coil wire and leaving the cap and rotor in place still leaves all those stray arcs jumping around..

It's been years since I've done so, but none of the distributor machines I operated required high voltage or a cap and rotor. The object was to check dwell, advance curve, and, depending on the design, either points float/bounce, or pickup coil/reluctor performance. Spark intensity was checked and monitored by a different machine AFTER the distributor was installed and engine running. This machine was often referred to as SUN Engine Analyzer. Later analyzer designs did not require removal of the distributor.. Patterns were displayed on a 'scope screen.

[jeff74]

Originally Posted by RustyPile

I don't know what "the numbers jump around" means??? What "numbers" are you talking about. Did you remove the cap and rotor and run the coil wire to a sparkplug.. Just powering the timing light from the coil wire and leaving the cap and rotor in place still leaves all those stray arcs jumping around..

It's been years since I've done so, but none of the distributor machines I operated required high voltage or a cap and rotor. The object was to check dwell, advance curve, and, depending on the design, either points float/bounce, or pickup coil/reluctor performance. Spark intensity was checked and monitored by a different machine AFTER the distributor was installed and engine running. This machine was often referred to as SUN Engine Analyzer. Later analyzer designs did not require removal of the distributor.. Patterns were displayed on a 'scope screen.

The numbers on the degree wheel keep changing because there's a spark every 45 degrees when connected to the coil wire directly, I'm using a regular timing light. Yes, I had the coil wire directly to the spark plug. It would work that way if you focus on the degree marks only, but it's a little distracting.

A simple version of a Sun distributor machine is what I'm going for. When I get my motor speed control in the mail (and my tach hooked up) I think it'll work

[Getter-Done]

Great job so far.

There are lots of different versions of this on U Tube (Of Course)

Your looks neater than
This guys,
He's got a lot going on.
But it Works.

Distributor Bench test Part 2 - Working - YouTube

[jeff74]

Originally Posted by Getter-Done

Great job so far.

There are lots of different versions of this on U Tube (Of Course)

Your looks neater than
This guys,
He's got a lot going on.
But it works

Thanks
I've seen a few videos and pictures of different setups. I made a tach sensor bracket today and then went ahead and destroyed the tach sensor , I must have reversed the leads.. Soooo...I ordered a new tach which should be here tomorrow and my motor controller should be as well.

I'm looking forward to trying it out

[Getter-Done]

Originally Posted by jeff74

thanks
i've seen a few videos and pictures of different setups. I made a tach sensor bracket today and then went ahead and destroyed the tach sensor , i must have reversed the leads.. Soooo...i ordered a new tach which should be here tomorrow and my motor controller should be as well.

I'm looking forward to trying it out

[jeff74]

I did a little wiring and fired this thing up again today. Now I'm down to just the two clip leads to power it, and the timing light clips to the battery as well. The motor control is just stuck down with foam tape and the tach is powered from a 9v battery.

I have a moroso spring kit, I tried the two light springs and the timing seemed to come in a bit early , starting at about 900 rpm and was all in before 2000. Then tried the two medium and it's a bit late. I'll record all the values if anyone's interested.

With one medium and one light spring I get this...
2 deg at 1200
8 deg at 1400
12 deg at 1800
16 deg at 2000
20 deg at 2200
22 deg at 2400... I filed the copper bushing to get it to 22 deg, that's the max

Base timing at 10 degrees is my plan. What do you guys think? Is 2400 a bit too soon for 32 degrees?