Two outta three ain’t bad
- I’m grizzled
- I’m old
You did a compression check!
Hello Paul,
Thankyou, but unfortunately only limited access through replying to email, strangely enough.
Best regards,
Bill
Craig,
Here’s a photo showing an OEM grounding strap installed. One end goes under the frame bolt and the other end installed under the top bolt of the locking bracket. Very important item. Yours may not be heavy enough to carry the load(s) back to the battery. Make sure they reach bare metal when installed. Also note other items that connect to the +Ve power block and the rubber hood, protecting the live end. You need that rubber boot!
Where did you connect the lead from the blue filter cap fitted above the voltage regulator? It also goes to the +Ve block.
Happy building,
Dick
Just remember: you can never have too many grounding paths.
Well – I didn’t know a grounding strap there was original. I’d always assumed the mechanic in Boston added it as an aid. Between MarekH’s comment and yours, it’s a no-brainer
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Yeah – I noticed I neglected to add the boots an hour after tightening down the last Whitworth nut.
I gotta pull it apart anyhow - I still need to add the Firewall Grommet and several of these wires are among those that thread thru it.
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Oops; not tellin’. Dang it
Just another reason to redo the Terminal Block and add the rubber boots;
Any recommendations vis-à-vis location(s) for additional grounding straps?
Since it appears the link needs to be made between the frame(s) and the chassis, I’m thinking one option
for another is where the rearmost under-body steel tube brace connects the left/right side frames in the foremost edge of the transmission tunnel.
While searching for a photo to show what I’m talking about above, I came across this photo of undercarriage on passenger side - looking rearward thru the trans tunnel
The bottom tube of the passenger side frame is through-bolted to the chassis (the 2 bolts at bottom center) . . .
. . . which are inches forward of the torsion bar mounting bracket (beside and just left of the ID tag) the inner most attaching bolt of which is lurking in the shadow.
Yes?
Possible?
Don’t do that!
I usually would install an extra one between the bonnet and the trapeze.
If you look at the last photo, the thick battery connection appears to be on the other side of the terminal bolt block to that of the starter motor. This would be an accident waiting to happen. It means that the starter current goes through the eyelet through the insulators. If you you thrash the starter motor too much, this will all heat up. That may lead to a serious accident. Always put the thick starter motor cable up against the battery positive connection. That is the safest option.
By the same token, it is pretty wise to run a separate equally thick ground cable from a starter motor bolt back to the battery direct. This sort of thing cost money back in the day and Jaguar built these cars for profit. You can do better.
kind regards
Marek
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Boy Howdy – that is worth the price admission, right there.
Worth repeating: Always put the thick starter motor cable up against the battery positive connection
Worth highlighting: Always put the thick starter motor cable up against the battery positive connection
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Craig,
Jaguar installed one Engine-to-Frame ground on the LH side as per this photo.
I’ve found adding a second grounding strap to the right side most beneficial. Both bolt to the bell housing. Ineffective or improperly installed grounding straps can cause serious problems. Once found a car with the RH bonnet latch/engine frame ground strap missing. The accelerator cable was also welded immovable. It became a ground, overheated and fused to the outer sleeve. Make sure all paint is removed where a grounding strap/lug, etc. is installed. Metal-to-metal is what you’re looking for!
C16919 Engine/Body Earth cable.
Happy Trails,
Dick
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Yes- and use dielectric grease on the interface to prevent future corrosion.
I have been applying dab of dielectric grease to every electrical fitting as I add wiring harnesses and components,
Good reminder though – Thanx
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^^This^^ will save you from untold issues in the future. I am convinced that most of the issues that gave Lucas the “Prince of Darkness” moniker were related to corrosion in un-sealed electrical connectors.
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I would have thought that most of the problems are due to inappropriate fuses. These allow up to 35 amps to flow and that is why smoke escapes. If the fuses were rated at the lowest value possible that still allowed the job to be done, then a component failure would lead to a fuse blowing long before wiring or connectors are damaged.
Corrosion and lack of sealing doesn’t cause a high current to flow. In fact it does the opposite. A high resistance means not much current can flow. You can have lots of corrosion on a low current circuit and smoke will never escape.
The design flaw is that the primitive fuseboard allows lots of current to flow per wire - far more than any individual component needs. Essentially you have a legacy item from the 1940s xk120 design but are using it inappropriately once lots more current hungry items have been bundled onto the same bus.
kind regards
Marek
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Well, I will throw in my perspective. Yes, one cannot have too many ground straps. But also, one cannot have too many positive cables. Just because one cannot have too many, does not mean there is any reason to have more than designed. The factory ground cables and connections have been adequate on this and most cars for many years. If there is a problem, I suggest fixing the problem, not going around it. It seems to me the main reason grounds seem to cause people problems is that maybe they ignore them because they are not easily seen, and maybe they are not proficient at troubleshooting them. Neither, IMO, a reason to add more. But as was said, more will not hurt, so add as many as you wish.
Next, yes, corrosion problems will typically cause high resistance. And higher resistance in a circuit will cause lower current draw- if the circuit is a resistive circuit. Such as a headlight, where the corrosion causes the bulb to be dim. However, cars have inductive loads- such as the starter motor. And yes, typically corrosion on the starter motor circuit will cause lower current and lower cranking speed. But not always. With a certain amount of added resistance to a motor circuit, it can cause the motor to crank a slower speed, which can cause the motor to operate at a very inefficient speed that will cause the amp draw to go very high and can burn up the starter motor. Note I did not say it always will, but it can and has ruined motors.
Tom
Marek- I had always assumed that the Prince of Darkness moniker came from electrical items not functioning or malfunctioning (dim/no headlights or tail lights etc.) not car-b-ques. Oversized fuses would not lead to non functioning or malfunctioning electrical items, but certainly could lead to letting the magic smoke out/car-b-ques.
Hello Craig,
Bill here.
Dielectric grease on the interfaces of your earth, is the last thing you would want to use. Its an insulator, not a conductor; you certainly don’t want an insulator between the contact faces (interfaces). Ordinary grease, or better than that would be bronze anti-seize compound; something that’s conductive.
Kind regards,
Bill
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I did not know that. It seems a common misconception.
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I missed that: NEVER in an electrical connector, just over the completed current path.