Fw: [Chrysler300] Battery/Starter-300F

["Jean-Yves Chouinard" <jymopar@xxxxxxxxxxxxxxx>]

Hi to everyone.
I'm forwarding this tread to the list server as it pertains to Tom's starter problems. It's from Club Member John Grady. He is an electrical engineer.
Jean-Yves Chouinard.
----- Original Message ----- 
From: John Grady 
To: 'Jean-Yves Chouinard' 
Cc: Ed Cornish ; Keith Simons 
Sent: Tuesday, March 30, 2010 11:28 AM
Subject: RE: [Chrysler300] Battery/Starter-300F


Hi,J-Y ; 

 

Maybe I can help. As an EE ,and PE, I have a perspective on it. Maybe you can pass this on...

 

First the starter as designed started thousands if not millions of B blocks and hemi's over the years , (at 10 below zero, too! ) and does not need redesign or new windings of heavier wire. Heavier wire draws more current, which drops the battery volts even more, and needs the same # of turns to get the same magnetism, which is what makes the force. The force is proportional to turns, as well as to current. As more turns of larger wire will not fit in the same space , it is the wrong way to go and may make it worse. The resistance of the wire does not change or deteriorate over time; it does increase a little when hot, but that is normal and was accounted for when the unit was designed. Anecdotal talk of how heavier wire improved things has more to do with just rebuilding the starter , new brushes etc. Heavier wire means an 8 volt starter is now used on 12v; pros and cons to that. Works great , fast spin on a nice warm day... may not turn at all when cold.

 

You can separate this into two problems1) the engine is hard to turn 2) the starter is not providing full force . It is critical to CLEARLY find out which it is (!) before doing anything, or you waste money and time.

 

 

Hard to turn, but starter OK,  is usually timing too advanced (distributor weights did not return, or wrongly timed, or "turned up' timing in pursuit of performance-this has a characteristic cranking sound, quick turn followed by almost stall at TDC, repeat .) , a mechanical bind in starter drive (tolerance of starter pinion to ring gear-it must not jam-loosen starter and move back etc; damaged or off center ring gear.) or something in the engine, transmission  or belt drive is dragging(unlikely, if car idles and runs OK). A too tight piston or ring fit in a rebuilt engine can REALLY aggravate things when hot... If starter is good, and you measure starter current draw, it will go way up when hot if engine bind is loading it down. Current draw on a good starter is always proportional to how hard it is to turn, if starter and battery are OK. . So, you really need to know that number; you must have a starter ammeter to say anything about what is wrong.

 

Second problem, not enough force from starter, is actually easy to troubleshoot. The service manual provides a starter no load speed and 'locked rotor " torque value...do what it says,  to find out the story! --and sometimes gives an ampere draw at locked rotor and free spin. You do need a starter ammeter;  !!! check the draw IN the car is job # 1 !!!, while cranking hot and cold and measure battery volts at the same time. The battery should stay at 10.5-11  or more , no matter what you do; if not, battery is in question..most common problem, or a cheap toy battery. Winter storage allowing it to die and then a spring charge cuts 50% out of a battery; a carbon load pile can find that.(Harbor tool)  . Always buy batteries by weight, not sales bullshit; the bigger / heavier the better; store inside on wood surface (no concrete) and trickle charge once a month for a 24 hour day. Leaving trickle charger on , even fancy 'self turn off" ones, can wreck battery by evaporating the water. . Cables must be heavy gauge, in good shape and tight. Cheap thin cables loose power, but any problems in cables or ends will be accompanied by getting hot when trying to start for extended times. Feel the ends for heat after cranking for a minute or so.  It is not generally necessary to scrape paint etc, as bolt has no paint and current goes through that side into block too. ..but it cannot hurt.

 

The free spin test in service manual checks for shorts in armature, as it will not rev up to high speed with a shorted armature; you also can check resistance from commutator bars to shaft, should be an open circuit...most shorts are from winding to shaft or core, but turn to turn shorts happen too...and slow down rev test.  Test field winding for shorts to frame too. There is a free spin rated current, it should be within 5-10%.The locked rotor test is a little tricky to do, but checks torque output vs. current draw; it draws very high current for that, which will find bad brushes or open windings in armature. Worn brushes imply a lower spring pressure, and I have seen brushes 'frozen" to the brush holders by long storage and so not pressing on the commutator; that leads to low torque and bad burning which destroys the commutator. Always free up brushes in slides, check them when rebuilding a stored car( generator, too) . Problems with armature can usually be found visually..a shorted turn will be burned, or commutator burned etc. = look carefully.

 

In the realm of weird things, I had a situation like this, it turned out to be the wire lead attachment  / big bolt on the starter frame of a 60 Dodge. It  was OK and tight on the cable, but the nut UNDER  the lug was loose, (!) which allowed the stud to move sideways in the steel and touch the starter frame, (sometimes......!)drawing huge current and barely turning,, intermittently. This, from factory. Loose starter bearings or off center ends can let armature touch field poles, but only when starter is on, magnetism pulls it sideways.  --that will totally kill output torque. 

 

New battery, generator , regulator , battery cables etc did nothing on that 60 Dodge, and a jump would start it , deflecting blame from the starter. Correctly tightening the under nut fixed it. So, I empathize....  Drove me crazy. Starter Ammeter is what found it. How much the headlights dim at cranking is a poor man's ammeter!

 

The solenoid MUST make the main contact solidly and be correctly  assembled, as it will spin weakly while engaging, but full torque doe not come until solenoid shorts out the pull in winding , which happens after pinion is almost all the way in. Tolerances in this are critical, someone may have rebuilt wrong. There is no need to run a ground right to the starter, as the engine block has a very low electrical resistance. In fact shorter, heavier  cables and a big fresh battery matter most .

 

The thinking should be: the stock setup is fine, something is wrong somewhere..they knew what they were doing. . At a bare minimum , you need a starter ammeter, and a voltmeter..and compare with a good car. 300F does not crank easily, but stock works fine.

 

Hope this helps,

 

John Grady

 

PS, gear reduction or "geared mini starters" non stock are better, but original is fine too. They are better as they have permanent magnets, no field winding, gear down gives it more torque at same current draw.

 

 

 

 

 

From: Jean-Yves Chouinard [mailto:jymopar@xxxxxxxxxxxxxxx] 
Sent: Tuesday, March 30, 2010 6:38 AM
To: John Grady
Subject: Fw: [Chrysler300] Battery/Starter-300F

 

This is the email from Tom Cox about starter problems...

J.Y.

----- Original Message ----- 

From: Thomas Cox 

To: Chrysler300@xxxxxxxxxxxxxxx ; parts@xxxxxxxxxx 

Cc: donbelton313@xxxxxxxxx 

Sent: Monday, March 29, 2010 10:14 PM

Subject: [Chrysler300] Battery/Starter-300F

 

  

Thanks to the many folks that have given advice. A summary of the suggestions:
 
1. Make certain the ground connection is to clean metal giving a good ground.
2. Have the rebuilder use heavier winding materials.
3. Ground the battery to the starter (with clean, unpainted connection).
4. Cool the starter with water to see if a reduced temperature makes the problem lessen to confirm the starter problem.
 
After all these, I contacted Jeff Carter who has bailed me out of many difficult issues with the 300F build. He indicated, in agreement with all the above, that it is likely a starter problem that may be due to multiple starter rebuilds (or just age) where the field windings have deteriorated to the point that they have too much resistance and are not funcioning properly and when the starter gets hot, it does not provide the electrical boost needed. That, and the probability that the windings of the armature are not the heavier-duty variety. He no longer knows of a shop that has the knowledge or the parts to do a proper rebuild with new field windings and armature rewinding. 
 
Do any of our members have a starter shop that has this experience and parts to do a complete and proper rebuild? It seems that may be the best solution to the problem at hand. I imagine other folks are having, or will have, a similar need. Louie Barrie indicated that he had a fellow with a great deal of knowledge about these things. Any leads would be greatly appreciated.
 
Tom Cox

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