Ground Straps

I wouldn't place body grounds very high on the list of things that would cause slow hot starts

first would be the starter itself, drawing too much amps when hot. next the battery cables, both/all of them! they can build a resistance over time that shows itself when hot. the terminals on the cables may be hiding a severe case of corrosion also

unless the timing is advanced to the point that it's an issue after the engine is hot?

Thanks, I replaced everything with the exception of the positive starter cable, doesn't appear to be corroded, but will have another look.

Is it possible to add a heavy ground strap on the starter to the frame?

for trouble shooting, you could use a "clamp on" DC amp meter and conpare cold versus hot.
another measurement would be voltage DROP from the battery to the starter terminal during cranking

Or get a PMGR starter (Permanent Magnet Gear Reduction) and solve your problems.

A heavy duty ground cable from the starter mounting bolt to a good spot on the frame certainly can't hurt anything, either....

Grounds are the root of all evil ... I have multiple grounds all over my hotrods, the cars seem much happier. Many times when I was a kid cars would have trouble starting, I would reach in and crank the ground, not at the battery but at the block, and the cars would start....

Sorry if I digress, but I had to reply to your comments.

quote:

Originally posted by PLT-1:
Grounds are the root of all evil ...

Even though I was mechanical, I worked an older anolog control system and I could not agree with you more...Grounds were the root of nearly all problems.

quote:

Originally posted by PLT-1:
I have multiple grounds ...

here is where I am conflicted, for the control system only ONE ground was required, having a second ground raised havoic.

I apoligize for the side track. I guess it is only amusing if you were there.

Joe

quote:

here is where I am conflicted, for the control system only ONE ground was required, having a second ground raised havoic.

I worked for an EMS (energy management systems) contractor for several years. Lots of multi-conductor (with one bare ground wire), shielded cables for a multitude of sensors - temp, chillers, boilers, HVAC, etc.

One of the techs - the 'brains' that came out after installation to bring the systems online - explained to me that we should only ground one end of the cables. Why?

If we grounded both ends, that bare wire became an antenna of sorts, and would then gather all sorts of EMF (electrical/magnetic field) interference, radiate it into the cable wiring, and screw up the low-voltage EMS sensor signals carried by the cable. We were also instructed to never run our cabling closely parallel to any electrical power conduits, and to only cross such conduits at right angles.

But for automotive applications, and especially with our Panteras, multiple, secure grounds are an asset, not a problem.

Larry - IBEW #100, retired

My favorite tech story was the one who came out to the new middle-school campus and started to berate us for faulty wiring, as multiple sensors were not displaying on his laptop system overview. Turns out those sensors were never placed on the blueprints used for our installation.

quote:

I wouldn't place body grounds very high on the list of things that would cause slow hot starts

I would. there is many a post on this forum describing the hot start problem. Mine got cured when I installed a new {additional) ground strap from the starter mounting bolt to an engine mount bolt.

...In My opinion, and most would agree, the 'Starter Motor' is the Single Most Important Electrical Device in Any Vehicle and Especially in Our Panteras!

It MUST Work, Or We are Going to Have a Very Bad Day!

To that End, I run a 'Beefy' (Thick as I can Find) Round Cable, Directly from one Starter Motor Mounting Bolt, to the Nearest Mounting Bolt, of the (removable) Cross-Member Support. Just to the Right of the Clutch Slave.
I Put one Loop in it for Flexibility.

The Resistance is Lessened with the Shorter Distance to Ground. A Higher Currant is 'Allowed'. IF one is still depending on the 'Woven' Ground Strap (Yuk) Original from the Factory, Connected to the Tail of the ZF Transaxle, Just think...the High Amperage Currant Drawn by the Starter, MUST conduct through the ZF Aluminum Case!! The Electricity, Possibly, in searching for a 'Path', For an Instant, may even travel through the Shafts and Gear Teeth!! Think about THAT one for a Moment!

In My Years of Experience with 'Power Transmission Gearboxes', our Team Once came upon a Very Large Gearbox, in for New Bronze Bearings. Powered by a 70 Horsepower 440 Volt AC Electric Motor, that was NEVER Properly Grounded!
We pulled the Shafts and found the Bronze Bearings were Impossible to Remove, as the Bronze had 'Eroded' to the Steel of the Shaft. Known as an 'Eddy'(SP?) Current.
So severe was the attachment, that the only way of removal was to mount the shaft in a Vertical Mill, and Mill Two Opposing Slots, the Length of the Bearing and all the way through the Bearing, to the Shaft, in effect splitting the Bearing into Halves.
Then the Work Started, I had to Wedge into the Halves and Hammer onto them with a 20 Pound, 3 Foot, Sledge Hammer. Took All the Might I had, About a half-hour, or More, later, I had 'One' Half Hammered Off. Another half and 2 Halves of the Second Bearing to go.

...One interesting fact, upon Close Inpection of the Bearing Half. The Erosion was evident in 'Rings', as in rings like 'Tree Growth'. Why? Because the Motor was Shut-Off every night and the Erosion only took place while running during the days. Every Ring represented a 'Few Hours Shift Period of Operation'. Almost 'Microscopic', there were Hundreds of rings, Eroding(I can't describe it as Welding) the Bronze to the Steel, UNTIL the Shaft finally Froze-Up, and came to a Dead-Stop!!

The point of all this would be, if You are running a Grounding Strap to the TAIL cap of Your ZF, and it is the ONLY PATH for The Starter to CONDUCT 200+ AMP's or More, it is MY Recommendation that You Scrap THAT Strap and Install a Thicker Strap Closest to the Starter Motor.

...For What It's Worth.

I have ground jumpers all over the cars... The chassis, body and engine are jumped together in various places...

I've added grounds at many spots on the cabin/chassis wiring harness, but grounds related to the starter are as designed, through clean metal (starter flange/bell housing/transmission housing/ground strap/frame)connected with clean tight fasteners.
I tend to believe that improvements noted after adding any other grounding means you have missed a compromised existing connection somewhere else.
Starting with the best, the most conductive metals are silver, copper, gold and aluminium. Steel is far down on the list. I don't worry about current looking for a path through the transmission bearings and gears when the easy path is through the aluminium housing.
Keep your connections clean and tight.