'35 Question: Engine Ground Strap

[Detonator]

Moving up the chassis of my new coupe I found there's no battery-to-engine ground strap. The motor must have been grounding through the chassis/motor mounts. Original 6V '35 coupe.

I see it takes a 12.5 inch 48-14301 strap -- but where does it bolt to the engine?

Thanks

Dave

[lotsagas4u]

Check your torque tube clamshell, the 1934 positive cable bolts to the upper left bolt.

[rockfla]

Doesn't battery ground cable bolt to the universal joint cap bolt, then some will run a ground strap from either starter bolt/bell housing bolt to frame OR Bell Housing bolt to frame??? I'm not at my book so going from memory

[Don Rogers]

The ground strap goes from the positive battery terminal across the frame to the bolt holding the left side of the universal cap halves together. See photos.

[Detonator]

Thanks guys!

[flatheadfan]

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I know it is not original but in addition to the original ground to the u-joint shell, I also have one from the starter mount to the frame and a smaller strap from the intake manifold to the firewall. Never hurts to have too many grounds!

Tom

[rockfla]

@Detonator
I would ad, I like to use Dielectric grease on all the bolt connections (ONCE GOOD AND CLEAN) to help keep a good clean ground.

[JSeery]

Or any grease, really no reason to use dielectric grease

[rockfla]

JSeery
I read all of your post and always take your wisdom to heart and memory.....BUT.......My best friend works a NADEP/NAS Jax for 33 years, several in the electrical/cable shop (Which is who turned me onto using dielectric grease) and which is used exclusively on most electrical connections, snap switches, etc etc on ALL P3 Orion's (including NOA Weather hurricane tracking P3's) the local NADEP rework facility reworks and is arguably THE Finest P3 rework facility in the world!!!! Regular grease "MAY" work ok for our pedestrian V8 Fords, I'll stick to the Dielectric grease AKA used on the P3's (and now the Boeing P8 Poseidon) for low attitude surface tracking of sub-marines over the worlds oceans to protect all electrical connections from the salt environments these aircraft are subject to on a daily basis. And IF there was NO difference then why make it, why don't they just use regular grease?

[JSeery]

Do you understand what dielectric means? It is used to block electric current flow. It has it's place (and an important one!) in electrical connections and electronics. It is used in modern auto electronic connections because you want to block current flow! When you have multiple pins in a connector anything that would allow current to flow between the pins would be a disaster. Same with a lot, and most likely the majority, of eclectic connections, if it is possible for current to flow between two points nothing can be used which would allow current flow, this is extremely important. It could not only cause a failure it could be very dangerous as well.

Now in the case of a single point ground on a car/truck or a battery terminal, why would you want to use a grease that one of it's main purposes is to block current flow? The truth is (if you check the testing of dielectric grease) there is not a great amount of blockage to the current flow in most connections. This is because there is enough metal to metal contact that the dielectric grease is not able to block.

So why use it on a ground (or any single connection for that matter) in an early Ford wiring system? On my cars I am interested in maximum current flow through all the connections and especially the grounds. I do not use dielectric grease on ground connections because I want maximum current flow, not to block current flow, even if it is only a small percentage! It probably doesn't make that much difference really, but to me, why use it.

On the Boeing reference, I worked for Boeing military for 35 years in electrical design, so understand the reference you are making. But this is a Ford car with a single current path that we are wanting to maximize current flow between two surfaces with no worry about current leaks to any other surface near by.

If you like dielectric grease, use it, but understand what it is and what it is for. I much prefer a conducting grease for a ground connection.

Here is the definition of dielectric grease if that is of interest to anyone:

"Dielectric grease is a non-conductive, silicone-based grease that's designed to seal out moisture and prevent corrosion on electrical connectors. It also disrupts the flow of electrical current, which makes it good for lubricating and sealing the rubber parts of electrical connectors. It's commonly used in automotive spark plug wires, recreational and utility vehicles, and electrical systems in aircraft."


"It can withstand high temperatures, making it a good choice for engine compartments and similar locations. Many dielectric greases are rated to work in up to 392° F (200° C) temperatures, and some can operate at up to 500° F (260° C). Though there are other greases that can work at these temperatures, they may not prevent the flow of electrical current like dielectric grease does."

[rockfla]

http://www.w8ji.com/dielectric_greas...ive_grease.htm Not to be argumentative but here is the link to the electrical engineer who helped develop such electrical greases.....as he states....NO apparent evidence that it interrupts current flow....as you stated in your post.....it is a good sealer and preservative grease.....it has a higher melting point than standard petroleum based grease and as this electrical engineer has stated "He uses it on battery terminals" "Especially grounds" etc. etc.

[JSeery]

I'm an electrical engineer! LOL Anyway, one of the main functions of dielectric grease is to block current flow, that is why it was developed and that is why it is used! That's what it is for. But, there are arguments all over the internet on this subject. What they are saying is that most of the dielectric grease is pushed out of the way and you get metal to metal connect so the current blocking characteristic of the dielectric grease is not a factor.

I don't have the slightest interest in arguing this topic. If anyone likes using dielectric grease use it. I just personally prefer using a conduction grease. So guess it ends up being a personal choice. On modern cars it's dielectric grease for me, for old Fords it's a conduction grease. But if you prefer otherwise, it will work fine and I'm not the least concerned by it! LOL

[JM 35 Sedan]

I don't necessarily want to get in the middle of this debate, but dielectric materials are normally considered to be good insulators which would prevent current flow between conductors of different polarity. Some examples are: mica, rubber, paper, porcelain, ceramic, cloth, most plastics, glass, phenolic/bakelite, etc.

I believe what's necessary in this case, which is a good ground connection, is to have the two conductive surfaces cleaned to nice bright bare metal, join those surfaces tightly together, and keep that joint as clean and tight as possible. This might require some type of non conductive covering or coating to accomplish.

[rockfla]

@ JM 35 Sedan
Your final analysis is kind of what my point was meant to be....There seems to be two arguments among Electrical engineers that could continue a debate until the cows come home...with that said....the one fact of Dielectric grease (sans which side of the conductivity argument you are on) is that it is a sealer and protector and here in FLA where humidity is king and salt in the air......All things being equal I go with what is a sealer, protector and a higher heat tolerance for longevity. As JSEERY has posted, its not to be argumentative, Nor do I question his expertise.....obviously either will work.....I was just passing along what I had been taught by the "experts" I have known on electronics and from that frame of reference.

[ford38v8]

I'm going to chime in here with my 2¢ worth.... Dialectic grease on our old Fords.... In and through the plug wire conduits, rubber distributor wire caps, and coil rubber caps. Definitely not for use in harness wire bullet connectors. Virtually all electrical connections benefit from sealants against oxidation, but casual connections such as bullet connectors should have a conductive grease rather than a dialectic grease. I'm not an Electrical Engineer, and I approve of this message.

[V8COOPMAN]

POS gnd, or NEG gnd? DD

[rotorwrench]

Dielectric grease will not affect tight connections, it is non reactive silicon, and most importantly, it keeps the elements out of the electrical connection. We put a little in the cannon plugs before we screw them together. We put it on any open terminal connection. Those that don't have it will fail a lot quicker than those that do. This has been an aviation staple since WWII. If you put a conductive material on a connection and it makes its way to another conductive surface then you have a short.

A dielectric only blocks electrical flow when a connection is not positive. It will keep a high tension connection like a magneto cap from cross firing between connector terminals. I've always used DC-4 (Dow Corning #4)for this stuff and I'll guarantee that the aircraft I work on are reliable or I wouldn't approve them for return to service.

[rockfla]

@ Ford38 V8
For what its worth department......On most of our cars where a "More Modern" bullet connector or spade connector is used, I pull the color covers off and use heat shrink to fully cover the connection, hopefully keep it fairly well sealed and not look as conspicuous with the red, blue or yellow connections!!!