I'm having issues with the new motor and cranking. When it's cool it cranks fine but, when it gets hot it doesn't want to turn. I've checked all the wires, made sure the battery is hot and putting out good voltage. I'm starting to think the Chrysler mini starter isn't strong enough. The motor is 557" / 14:1. What you think? What starter do you recommend?

I had that problem, but I had to rewire the whole car, it was a shell. I hadn't used enough grounds or big enough wire, now I've more than I probably need, but starts fine.

Did you miss a ground wire when you put the new engine in? Just thinking out loud. Mine is 499 and at 12 to 1. I use a mini starter as well.

How close are the header tubes to the starter? Maybe a heat shield is in order. Poor or lack of ground capacity is very high. What is the battery CCA? What size cable are you using to the starter from the battery?

Try disconnecting the ignition pickup when this is happening. You may just need a bit less timing with temp.

We went after the ground first and did find some wiring that needed to freshened up so that is done.

I have a heavy cable (welding cable) going to the started.

It's going to get a heat shield today. I have the mazzaloni headers

Haven't tried the pickup idea. I'll try that today also

My 15-1 572 uses a stock starter. Header tube nearly touches at the front of the starter. I run 2 batteries and they need a decent charge in them. It starts with 32 degrees, ignition on. It cranks way easier with the ignition off but with the track record of the 440-25 intake exploding thats a no no. I've found the batteries to be more of an issue than the starter itself. Just disassembled the starter for a look see after over 400 passes. Except for some arcing on the solenoid washer and contacts it looked like new.
Doug

never had a prob with my JY mini starter in my 15-1 big block.

I know you have a big enough wire for the positive, but how big is the ground wire? That was my problem, from what Ive read, the negative needs to be as big. After I went with a bigger ground wire, mine starts right up, hot or cold.

I know a few people who had trunk mounted batteries that were just grounded to the chassis in the rear, that found a definite improvement with hot cranking by running a full sized cable from the battery right to the block.

instead of guessing, why don't you do a voltage drop test, that way you can find the problem quickly.

FYI we use a stock mini starter to turn over a 500CI 14-1 8-71 blower engine, works fine.


Joe

Voltage drop testing is one of the simplest tests in the world to do, but often is over looked. Here is a detailed explanation of how to perform the test.

You will need a volt meter, preferable a digital one. The help of a friend will make testing a lot easier as well. And possibly a set of booster cables if the circuit you are going to test is really long.

A few things that you should know first. When you use a volt meter it displays the difference in voltage from one lead to another. So when you place it across the battery on the + and - posts, and it reads 12.79volts, it means that the difference in voltage between the two posts is 12.79volts.

All the circuits in your car complete themselves at the battery, specifically between the + and - plates inside the battery. So any extra resistance outside the battery, any where in the circuit is a bad thing.

Industry standard for automotive production cars is a .5 total voltage drop in any system. Except maybe your starting system, as the old style starters just draw a ton of amperage. The .5 is divided up as .3 positive and .2 negative. So when we are testing the positive leg of the circuit we will want to see less than .3 of a drop, and less than .2 on the negative side. This is while the device is in use. i.e. if you are checking your lights, they need to be on while doing the check.

So here is how to do the test. Put one lead on one point of the circuit, and the other lead at another point. Say at both ends of a wire. The meter should read zero. Now turn on the device. The reading on the meter is how much the voltage drops between the two leads. If it is on both ends of a wire, then it is how much the voltage drop down that wire. If it is over .3 + or .2 - it needs to be replaced.

Here is an example testing the starter system on an older Ford. It is slow cranking, with a new starter and battery, so we will check for voltage drop issues. First thing we do is put one lead on the positive terminal of the battery, and the other lead on main post of the starter. Try starting it and we get a reading of 1.5volts. So we know there is a 1.5 volt drop on the positive side of the circuit.

So leaving the lead on the battery, we move the other lead up to where the main battery cable from the starter goes to the fenderwall solenoid. We repeat the start, and still get a reading of 1.5volts. So we know that cable is not the problem. (Could have also put the leads on each end of the wire to determine this, but takes longer to do the test).

Next you put the lead on the solenoid's post, and try the test. Still 1.5volts, so we know the connection between the post and the starter cable) is good. So we move the lead to the other post of the fenderwall solenoid, and repeat the test. Now we get a reading of .5 volts on the meter, instead of the 1.5volts. So it would appear that we are losing 1 volt through the solenoid. To confirm that we can put a lead on each post of the solenoid, and try starting it. In this case it does confirm that we dropping 1 volt through the solenoid.

But we still have .5 volts drop. So now we check the cable end at the solenoid, to the battery post. It reads .5volts still. So we then go to the battery post to the cable end at the battery itself. We get a reading still of .5 . So that would mean that between the battery post and the cable end we are losing .5volts, in other words, we have a bad connection.

So you replace the solenoid, clean the battery cable end at the battery. Also preventive clean the solenoid cable ends too. Test the complete system down to the starter again, and get a reading of .2 volts. So we are happy. Moving over ot the negative side. You move one lead to negative post of the battery, and another lead to the body of the starter.

You start the motor and getting a reading of .7 on volt meter. Now you just follow the ground path back every where there is a connection. So first you would go from the negative post to the bell housing, then block, then the ground strap clamp at the block, then to the frame rail, etc, etc. Where ever the drop goes away, then the what ever is between your last point and the new point is likely where the drop is. Always double check it by actually putting the leads on both ends of the item being tested (both ends of a wire, between a clamp and bolt, two posts on a solenoid or relay, two posts on a kill switch, etc).

It should take less than a couple of minutes to check a complete circuit. If the circuit is really long, say with the battery in the trunk. You can clamp a booster cable to the battery, and then to the one lead of the meter, thus extending the lead's length. You can use a small wire even, just booster cables are readily available.

(copied from another site, best explanation i could find)


Joe

Excellent troubleshooting guide !

I use this method of trouble shooting on a lot of different types of electrical systems encluding my car stuff. It works!

The only thing I would add if you use a auto ranging meter pay attention to the decimal point

Any start retard on your ignition box that would help also

Jack if you want to do a voltage drop test I will gladly come over and help you guys if you like. I have been doing voltage drops test most of my auto tech career. And to my surprise most techs dont know how to do simple voltage drop testing. In fact most basic techs I talk with dont even understand it. I had to do it on my 63 last winter when I had a cranking problem even with a new battery. I agree with everyone about the mini starter also as my eng is only 10.6 comp but I have used them since the late 90's with no problems. I can bring my fluke meter over also to use if you dont have one. Ron

For what its worth. My voltage drop on the hot side using 1.0 cable going through a brass pass through at the fire wall then a 12" 1.0 to the starter is .5 volt drop. It was measured from the starter stud to the positive post. Ground side uses a 8" 2.0 cable bolted to a welded stud on the cage near the battery. A second 6" 2.0 cable bolted from a weld nut in the torsion bar cross member to the trans case. The drop on the negative side is .1 volt. That was measured from the starter case to the negative post.
Doug

Well, it sounds like the starter is not the issue. Our ground cable is a decent size at the starter and it's a elephant ear setup so the motor should be grounded pretty well. Although, the battery is grounded to the frame, wonder if that could be the issue? I think the voltage drop test is going to be the next step. Thanks for the instructions.

Ron, I'll mention something to Dad. He probably knows the procedure for the voltage drop but, I'm sure he would take the help.

We are also going to try throwing a ton of voltage at just the starter with two batteries.

I have a feeling we're going to find a voltage drop issue. When the starter hangs which is only on a hot motor. Everything is drawing down (lights, pumps ect....)

Honestly the frame on a back half car is usually not the best place to ground the battery. I prefer a floating ground system myself that brings all the grounds back to the battery basically. A voltage drop test will show where the issue is. I would NOT use just the motorplate mount as a ground. I would like to see a ground from hear to head then to the floating ground or at least a very solid place on the frame. Try an experiment and connect a cable from the battery to the starter to provide a ground and see If it changes. My guess is you need better grounds.

Check the route of the cable and make sure it's not anywhere too close to frame steel, the Heat in the cable when cranking can actually melt through the insulation and actually short to the frame....so the ampacity will go WAY up in the cable but less current will get to the starter and it will still turn, but way slower.

Well, today we tried a few test. Ran a ground wire directly from the battery to the starter and also threw 24 volts directly at the starter. Neither really worked. We can't seem to get the motor to run cool. We're not running a thermostat so I added a restrictor plate hoping to cool it down and it still wants to run up near 220 degrees. The motor cranked fine at 190 but, anything above that it starts acting up. I'm thinking most of these issues are related to the temp. It's a 2 row radiator with a 16" 3000 cfm electric fan. This same setup was on my 500" with no issues.