[DeTomaso] Grounding Circuit Recommendations

[Tomas Gunnarsson]

Bellhousing is the key word here. The starter mounting bolts thread into the aluminum housing, not the engine block.

Tomas

----- Original Message ----- 
From: "Doug Braun" <doug at silicondesigns.com>
To: <MikeLDrew at aol.com>; <scottcouchman at yahoo.com>; <detomaso at realbig.com>
Cc: "DeTomaso Forum" <detomaso at realbig.com>
Sent: Thursday, January 03, 2008 7:53 PM
Subject: Re: [DeTomaso] Grounding Circuit Recommendations


> Three grounds may be overkill but I found on my car that the stock ZF ground
> strap is not adequate.  When I measured the voltage during cranking between
> a
> starter mounting bolt and the stud where the rear ground strap attaches to
> the
> ZF, I measured a large voltage drop of over 1V.  Cleaning the rear frame
> ground
> stud and the stud on the ZF where the ground strap attaches made no
> difference.
> By adding a second ground cable from the rear frame ground stud to one of
> the
> right side bell housing to engine block bolts, this same voltage drop was
> reduced to 0.1 V and now the starter never fails to run fast, even when it's
> hot.
> 
> My guess is that the aluminum case sections in the ZF have poor connections
> between them due the natural oxide layer that readily grows on all aluminum
> surfaces.  These thin oxide layers make for poor electrical connections.
> 
> Connecting to a bell housing bolt is nearly equivalent to connecting
> directly
> to a starter mounting bolt because of the massive 351C cast iron block
> connecting them.
> 
> You can do your own voltage drop measurements with a simple voltmeter during
> cranking by disconnecting the coil primary wires (so the engine will crank
> but not start).  Connect the meter at the various connection points along
> the
> positive cable and solenoid and then the negative cable paths to the
> starter.
> This will show you where you are losing voltage while cranking so you know
> where improvements may be needed.  It also requires two people, one to man
> the voltmeter and one to work the ignition.
> 
> Doug Braun
> blue 73L #5505
> 
> -----Original Message-----
> From: detomaso-bounces at realbig.com
> [mailto:detomaso-bounces at realbig.com]On Behalf Of MikeLDrew at aol.com
> Sent: Wednesday, January 02, 2008 10:32 PM
> To: scottcouchman at yahoo.com; detomaso at realbig.com
> Subject: Re: [DeTomaso] Grounding Circuit Recommendations
> 
> 
> 
> In a message dated 12/29/07 6 26 43, scottcouchman at yahoo.com writes:
> 
> 
>> Any suggestions or thoughts????
>>
> 
> Besides the stock ground cables (one from the tail of the ZF to the chassis,
> a second from the negative terminal of the battery to the main ground lug),
> I
> ran a third ground from the back of one cylinder head to the mounting bolt
> for
> the spreader bar, above the gearbox.
> 
> Three grounds is overkill.   Your proposal sounds ludicrous to me (but a LOT
> of people know more about electricity than I do and I am more than happy to
> be
> corrected in my assessment by any of them!)
> 
> Mike
> 
> 
> 
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