starting problems?

[warpspeed]

Dont' know if this is the best place to discuss this, but, here goes.

71 Challenger with a 440 engine.  Been driven 13 years now to about 18,000 miles total on weekends only.  Battery in trunk, #2 cable to starter, mini starter. Headers.  Block has been decked .020 to remove the warp when it was rebuilt.  10 to 1 pistons.  I have no problem starting the engine when is it cold.  Battery terminals are completely disconnected when not in use.  There is a lot of corrosion lately because of all the rain we have had.  Charging system is working great or it wouldn't start like it does when cold.  And I have put the charger on it when this happens and it quickly indicates the battery is fully charged.  But, not a single battery in the fleet will start the engine when it is hot.  Stop the engine when I  stopped for gas.  Get back in car and can not get the engine to restart.  Sounds like battery is dead.  BUT, it has good voltage.  Wondering if need more cranking amps.  Only recently has this become a problem.

Last weekend, I was coming home in rain.  Blue lights came on behind me.  Oh, oh.  Cop who stopped me wanted me to stop the engine while he was checking out my license.  I said ok if he was willing to give me a jump if the engine wouldn't start.  On no!  Don't shut it off.  He asked me if the transmission was in park,  I confirmed and told him I wasn't going anywhere.   He said ok, and went back to his cruiser.  When he came back, (engine still running), he gave me my information back and I drove off, no problem. 

Not sure if this is an engine with too much compression that has gotten hot, expanded pistons, etc. and  locking up on me.  If someone comes by and adds a jump from their vehicle, it starts right up.  Anyone use two batteries with high compression engines?  This has plagued me for as long as I have been driving the car.  It is just now getting worse.  Curious.

[A383Wing]

you need corrosion free cables & probably thicker ones if battery is in trunk

[warpspeed]

Haven't heard of corrosion "free" cables.  We have had so much rain this summer that the terminals keep messing up, but even after cleaning (almost weekly) that hasn't helped.  But, today is very dry.  Still having problems.  Been thinking of putting the battery  back up front.  Might try that first.

The only problem with putting the battery back up front is I need a new panel above the frame rail on that side, (I do have a new one already) but to tear the car down right now is totally out of the question. 

[A383Wing]

Haven't heard of corrosion "free" cables. 

seriously??

[MaximRecoil]

As mentioned by A383Wing, you need bigger than 2 AWG cable for a ~15 foot run to the starter. 2 AWG is a typical size cable for a normal front-mounted battery. You should have 1/0 AWG as the minimum, and 2/0 would be better. And make sure you get real 1/0 or 2/0 AWG wire; measure the diameter of the conductor to be sure. The conductor of a 1/0 AWG wire is a little larger than 5/16" in diameter, and the conductor of a 2/0 AWG wire is a little smaller than 3/8" in diameter. There are a lot of shady companies that sell "1/0 gauge" wire that has extra thick insulation to make it look fat, and has a conductor size of about 4 gauge. See the comparison pictures in this thread for an example.

Your main ground wires are just as important as the hot wires. Use at least 2 AWG wire from the negative post of the battery to a nearby point on the chassis, and make sure you have at least a 2 AWG wire from the engine block to a nearby point on the chassis. You can use the smaller 2 AWG wire for the grounds because they are short runs.

Also, clean your terminal clamps and battery posts thoroughly and coat them with grease. The grease will prevent future corrosion.  

[Pete in NH]

Hi,

I would run that negative battery terminal wire directly to the engine block at a starter mounting bolt with the same heavy gauge wire used on the positive side. Grounding the negative battery lead in the trunk area forces the current required for the starter, which is quite high, to flow through the steel unit body which after 40 years is going to have quite a bit if corrosion in places. besides even if it were clean , steel isn't nearly as good an electrical conductor as copper. Trunk mounted battery schemes are difficult to do well because of the high currents involved and fairly low voltage of which you can't afford to loose any.

[MaximRecoil]

Hi,

I would run that negative battery terminal wire directly to the engine block at a starter mounting bolt with the same heavy gauge wire used on the positive side. Grounding the negative battery lead in the trunk area forces the current required for the starter, which is quite high, to flow through the steel unit body which after 40 years is going to have quite a bit if corrosion in places. besides even if it were clean , steel isn't nearly as good an electrical conductor as copper. Trunk mounted battery schemes are difficult to do well because of the high currents involved and fairly low voltage of which you can't afford to loose any.

That's correct, it isn't, but there is way more of it, i.e., thousands of pounds of it. The unibody is all welded together at many points, and if rust has penetrated/saturated the welds, you have far worse problems than starting issues; the car shouldn't even be on the road because it would be falling apart. In other words, the length of the car relative to the mass of the conductor means there will be no practical difference in the resistance of a short run through the steel chassis or a long run. It eventually has to go through the cast iron engine block to reach the starter's ground point anyway.

People routinely run several-kilowatt audio amplifiers (a typical starter pulls about 150 amps, which is about 1.9 kW of power) mounted in the trunk of the car, grounded via a short wire to the chassis, with front mounted batteries, reaching sound levels of 150 dB or more, without issue.

Running a 1/0 or 2/0 AWG ground wire all the way up to the engine block is certainly an option, but it is far more expensive and more of a hassle, and I'm skeptical of the idea that there would be any meaningful difference. Because of the much greater expense involved, I would only try it if grounding through the chassis with two short runs of 2 AWG wire on either end of the car proved to be insufficient.

[John_Kunkel]

If someone comes by and adds a jump from their vehicle, it starts right up. 

If the jumper cables are connected to the existing battery cable I'd say that rules out the cables as the problem. Have you had the battery load tested?

[warpspeed]

Wow! Super great information.  I will check everything on the car as far as ground wiring, cable sizes, etc.  I appreciate the information.  Seems no one thinks it is because of higher compression.  So, I will rule that out.

John_Kundeln, yes you are right, jumpers are connected straight to battery and it starts right up.  I am going to get the battery(s) tested this week.  Still thinking about a higher amperage battery for this car.   I have always had more trouble after engine was warm than my other cars over the years.  And that was before I moved the battery to the trunk too.   Have a local battery guy nearby that can check it. 

[Edgar]

If we are talking about starting then we all know starting of anything is not that easy until we don't become efficient enough.

[myk]

Huh?

[MaximRecoil]

If someone comes by and adds a jump from their vehicle, it starts right up.

If the jumper cables are connected to the existing battery cable I'd say that rules out the cables as the problem. Have you had the battery load tested?

It doesn't rule out the cables as the problem. If the cables are the problem then in this case it means they are marginal for the task (as opposed to being completely not up to the task), because the engine will start fine in some circumstances but not in others. In the difficult starting conditions, it could be a case of the cables having slightly too much resistance relative to the battery's amperage and/or capacity, to start the engine. When getting a boost from another vehicle, you ~double the battery's amperage and capacity, and if the vehicle providing the boost is running, you also increase available voltage. This can be enough to tip the scales in your favor and get the engine started, despite the marginal cables.

One way to find out for sure is: the next time the engine won't start, hook the battery up at the front of the car, using a positive battery cable of only 3 feet or so connected to the starter solenoid, and a negative battery cable of 1.5 feet or so connected to the engine block. If the car starts, then the cables are obviously the problem.

[warpspeed]

Found out what the problem is!!!

My engine was set up with the standard mopar starter.  It was getting "heat soaked" from the headers after driving around for awhile.  I didn't realize that the starter was not the newer mini starter.  I am changing the transmission over to the 68 Charger for Christmas.  I will get a new mini starter for the newly rebuilt 440 that is going into this car. 

I still wonder if a more powerful battery will solve this problem though.  As I noted, when I was stuck at the gas station a few times, someone would undoubtly stop by and jump the car off.  Wouldn't have any problem getting the engine to start then.  But, only with another battery hooked up to jump the car off.  Curious.  If that is all it is to solve this problem, then a stronger battery is the answer so we continue to use the mopar standard starter. 

My question for everyone to think about.  I would really like to continue to use the standard starter.  Of course a blanket for the starter would be another solution, but not sure it is an easy, good looking solution.

[Cooter]

Batteries in trunks need huge cables. Plus make sure that weakass Chrysler alternator is putting a full 14 volts back to battery. Voltage drops can really kill your day when battery is in trunk. I know, my Dart is in trunk and is a PITA to get started hot even with mini starter.

[warpspeed]

believe me I am taking the battery out of the trunk when I start this car back up.  My dart, a 340 with headers ,had the same problem  before switching to a mini starter and its battery was in the front in the proper place.  still want to know if a diesel battery would have solved the heat soak problems.  I think it could have used a more powerful battery.

[Cooter]

You can force that burnt up starter to perform with a bigger battery, right up until the point it won't turn over at all.
The reason the starter is hard to crank when 'heat soaked' is it takes more and more amps to turn a dragging starter.
Now, your burning up starter wiring, relays, etc. Until you are forced to do what you should in the first place but don't want to.....


Replace starter, and heat shield it.

[RallyeMike]

Could it be that when the car was jumped that the starter had just cooled down by then? There is no reason high compression engine and battery in the trunk should not work fine given previous advice.

[warpspeed]

Not much chance. 

It was always at the gas station.  Pull up, shut off engine, pay for gas, pump gas, jump back in, hit the ignition, then the starter will barely turn over.  It was as if the battery was almost dead.  I would clean the terminals until some one would come by and start asking about the car.  Then, I hooked them in to help me jump the car.  Vroom, it would start right up.  I can assure you that the battery wouldn't do it on its own. 

But, at the house, when it is cool, it would start up without trouble.  I could go anywhere for miles, park it and after it cooled off, it would start up without problem. 

I checked the voltage in the battery, and it was always coming up ok.  Then, change batteries, same problem.

[Cooter]

Again, you need to make sure it has a wire from alt all the way back to battery for charging.
My Dart will do this as well. 1000 cca 900 ca battery too.
Your trying to put a bandaid on open heart surgery just getting another battery. The starter once warm draws more amps when trying to crank.  That stock Chrysler alt ain't helping either.  That thing is barely enough when everything is working correctly.

[warpspeed]

Cooter, you are great!  I had run the cable from the alternator to the relay first, the cable goes from the starter to the battery with a jumper from the relay to the alternator.    I don't use the ammeter in the car at all.  So the power into the interior is from the battery not the alternator.  So, it is better than original.  I really don't know the size of the wiring.  I bought the car  thirteen years ago with the "battery in trunk" wiring already set up.  I bypassed it at first with the battery in engine compartment because I didn't want any trouble with the remote battery issue.  BUT, finally, the battery support collasped due to the corrosion under the battery.  I reluctantly moved the battery  to the back.  I didn't have any trouble with it until this summer.  So, you are probably right, the starter is going.  I really  didn't have any problem before this and it has been more than five years with the battery in the trunk. 

Now, though, the car has been torn apart.  I am moving a lot of parts to the Charger I am bringing to life, soon.  I am almost ready to start the Charger up.  Therefore the Challenger is going to be broken down and rebuilt.  A lot of panels will be replaced and especially the battery support in the engine bay.  I am going back to original.  So, this problem will be dealt with now the correct way.

As for the Charger.  I am going to consider replacing the starter and adding a blanket for I will have headers on this car too.  I could go to a mini starter, but I really have too many good starters I can use.   Suppose I just need a blanket.

[myk]

Interesting thread.  So....if I get this right, a battery-in-trunk setup can be reliable as long as the cables are of the proper gauge, the battery is of the proper rating, and the starter is properly shielded?  Would the starter shielding be a custom deal, and if so what material?

[Cooter]

Interesting thread.  So....if I get this right, a battery-in-trunk setup can be reliable as long as the cables are of the proper gauge, the battery is of the proper rating, and the starter is properly shielded?  Would the starter shielding be a custom deal, and if so what material?

Hashtag= starter heat shield. Jegs, summit Racing, etc.

[A383Wing]

I would put a shield around the starter instead of wrapping it in a blanket...my opinion

[warpspeed]

Finally finished the starter installation on the Charger this past week.  Went out to dealership and bought a mini starrter.  Fit like a glove.  Wired it up and i am getting ready to install the headers today.  I am not looking back now regardless.  I believe this is the best way for me to handle this problem.  Thanks everyone for their imput.  Happy new year.