Lotus Elan

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PostPost by: prezoom » Mon May 15, 2017 3:28 pm

While entangled in a mass of wire in the engine compartment yesterday, I was busy running/replacing grounds/earths, the most troublesome electrical part of fiberglass cars. In the process, I was looking for a good place to terminate the ground between the chassis and the engine, when it dawned on me that there was a very nice threaded lug in the unused hand brake cable bracket. Nice, very secure place to install a short piece of cable between there and the engine block.
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PostPost by: billwill » Mon May 15, 2017 8:46 pm

You don't need to connect to the engine block itself as that has a nice thick braided copper strap cable to connect engine block to chassis.

In fact connecting thin wires to the engine block might be a bad idea, because if the contacts of the above mentioned earth strap got dirty the thin wire might attempt to carry the starter motor current, which would overheat the thin wire and maybe burn it out.
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PostPost by: prezoom » Tue May 16, 2017 12:44 am

Those are the two points I plan on installing chassis to engine ground. This work is part of the Zetec installation and I was looking for the best possible grounding point. A threaded lug, welded into the chassis met those requirements. That ground will be a short section of number one multi strand cable. The small wires in the engine compartment are now terminated at the body to chassis bolts. Interestingly, I did find a couple of small gauge ground wires that had been hot enough to melt the insulation. Thus the complete going over of the entire wiring harness in the engine bay.
Rob Walker
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1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe

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PostPost by: billwill » Tue May 16, 2017 11:53 am

I think the grounding strap is usually fitted to a bolt that goes through the fibreglass from engine compartment into the RH turret, but I'm not very sure of that.
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
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PostPost by: prezoom » Tue May 16, 2017 3:51 pm

I am thinking that converting a Plus2 to a Zetec engine is not exactly normal. When looking for the best possible place to attach the engine ground (B-) to the chassis, a bolt passing through a painted bobbin to an also fixed threaded connection, seemed to provide a less secure ground that what was offered by the unused hand brake adjuster location. This position puts the cable connector directly in contact with the chassis as well the bolt. My new ignition system also requires a very secure B- ground, so this new location will serve both . I am not exactly enamored with the grounding connection on the opposite side, i.e., through the bobbin. I gave some thought of welding a bolt to chassis on the front suspension turret just above the vacuum tank. I wished I had done that prior to painting the chassis. Grounds being the most troublesome part of an electrical system in a fiberglass car need all the help that they can get. The B- battery ground connection in the trunk was also augmented with a short section of equal cable from the single ground point in the trunk to the adjacent chassis/body connection a couple of inches away.

I also installed additional fusing, augmenting what was already existing. Both brown B+ battery leads that connect directly to the ignition and the lighting circuits were not fused and now are. Though the lighting circuit does pass through a thermal breaker, but nothing between the solenoid and the breaker. The new fusing location is next to the solenoid. I installed relays to down load the current flow through the switches that control the air horns, the headlight raising motor, the radiator fan (enlarged to 12") and the new ignition. All of the B+ battery to those relays are also fused at the new location.
Rob Walker
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1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe

Owning a Lotus will get you off the couch
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PostPost by: mbell » Tue May 16, 2017 9:35 pm

Your grounding suggestion sounds good to me and I think will offer a easier more reliable connection at the cost of a few extra grams. No doubts the normal engine mount bolts work well enough if done right and kept in good order.

Need to revisit this in my car as it struggles a little to turn over fast if the battery isn't absolutely 100% since I removed and refuted the engine. So suspect my ground connection could be better.

On a side topic I've a spyder suave frame chassis on the wall watering to be fitted. This has a couple of bolts just behind the front turrets that is not 100% clear what they are for. So I guess they're meant to serve as good ground connections for the front.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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