Joel,
Is the drop on the power side or the ground side? You should check both
side, and repair the side that has the excessive drop.
If for example the power side has a 2.0V drop and the ground side has 0.2V
drop changing the ground cable is not going to help.
One problem that shows up on show cars and fancy hot rods is they paint
everything before assembly and they have paint to paint contact between the
starter and the bellhousing and between the bellhousing and engine and
between the engine and the ground strap. The result is a very pretty car
that won't start.
You need good metal to metal contact.
good luck
Rick
On Mon, Aug 8, 2011 at 8:22 PM, <gardner5 at comcast.net> wrote:
> I appreciate everyone's input, and the info it's providing. In my
> particular situation, the battery is new and has been tested. The volt drop
> testing is being performed by an actual professional (he owed me a favor and
> I wanted to make sure I wasn't missing something). The starter has just
> been rebuilt, again by a professional shop. So my plan is to re-check the
> ground from bellhousing to chasis for good contact and check the cable
> connection contacts, volt test again, and then replace the cable with a
> larger diameter.
>
>
>
> Joel
>
> BN2
>
> ------------------------------
>
> *From: *"Richard Ewald" <richard.ewald at gmail.com>
> *To: *"John Harper" <ah at jharper.demon.co.uk>
> *Cc: *gardner5 at comcast.net, "Tom McCay - Classic-Car-World Ltd" <
> enquiries at classic-car-world.co.uk>, healeys at autox.team.net
> *Sent: *Monday, August 8, 2011 7:31:31 PM
>
> *Subject: *Re: [Healeys] Fw: volt drop
>
> I'm sorry but these specifications make no sense, and are not supported by
> any literature I have read in the automotive field over the last 40+ years.
> A 2 volt drop in a starter circuit is huge. A 2 volt drop is border line
> no start on any car. The industry specification is 0.3V for the positive
> cable and 0.2V for the negative cable. Note some sources say 0.2V for both
> cables. Remember we are talking about the voltage drop or difference in
> potential between the battery end of the cable and the starter end of the
> cable, so we are discussing just what is being lost in the cable and
> connections, not the draw down by the starter.
> Torque at 1,000 RPM? Starters turn the engine at 200-300 RPM period. Don't
> believe me? go out to your Healey, crank it and look at the tach. It is not
> showing 1,000 RPM 15.5 foot lbs of torque from the starter? I have no clue
> what this is supposed to be or how you are going to verify it. Talk about a
> useless number.
> 570Amp draw on the starter as normal? No way, no how. Normal amp draw on
> a gas engine starter is in the 100-150 amp range. I would expect a Healey
> to draw in the neighborhood of 125 amps or so. Most batteries won't deliver
> 570 Amp for more than a few seconds. For a comparison a high compression
> big block Chevy motor with a bad starter will draw 300 Amps and barely turn
> the engine over. Also a 300Amp draw the battery cables get hot from the
> amount of current.
> Locked up torque? No idea what it is, but 900A draw? You will melt the
> cables. This is basically a dead short across the battery terminals. You
> are discussing major league arc-welding here. 900A at 12 Volts is about
> 14.5 Horsepower.
> Likewise a 115Amp hour battery? I don't think so. Gas engine cars
> typically have a 30-45 Amp hour battery. The replacement battery that Moss
> sells for a big Healey is a Westco and is rated at 31 amp hours. sounds
> about right based on my experience. A diesel Mercedes has a fricking HUGE
> battery, it is rated at 88 amp hours, and you are telling me the Healey had
> a battery almost 50% larger than that? Nope, not buying it.
> Rick
>
>
> On Mon, Aug 8, 2011 at 12:46 PM, John Harper <ah at jharper.demon.co.uk>wrote:
>
>>
>> Joel
>>
>> A larger diameter cable will do no harm and perhaps give the starter a
>> little more 'sparkle' but the original cable to the correct specification
>> with good terminations is quite adequate.
>>
>> 2 volts drop is not that great. Bear in mind that the official test
>> specification for 'our' M45G starter is
>>
>> Torque at 1000 r.p.m.: 15.5 lb.ft with 570 amp at 8.8 terminal voltage
>>
>> Lock Torque 32.5 lb.-ft with 900 amps 6.4 terminal voltage.
>>
>> This with fully charged 115 amp.hr battery at 10-hour rate.
>>
>> So taking the first 1000 r.p.m. as being a typical starting figure we have
>> about 4 volts drop and this with short test leads used on the rig and a good
>> high capacity battery.
>>
>> It is more likely that your battery has an increased internal resistance
>> due to age etc.
>>
>> Before changing anything else I would try an alternative battery.
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