1938 Ford "6 volt ground problems"

J

jhstal

Junior Member
My 1938 Ford tudor deluxe early (nov 37) 221 engine has the dash mounted ground strap mounted to dash stud correct, but has the other end to rear of intake manifold. What is correct?? Is it suppose to be mounted on right rear cyl head under one of the two rear head stud nuts? Upper rear head stud has the nut flush with top of stud. Lower head stud is longer and has extra room to mount cable, but is already has factory (??) mounted exhaust bracket hanging from it to exhaust pipe. Any thoughts.
 
While I don't know what's factory correct, it's likely not a good longterm solution to attach a copper ground strap to an aluminum casting held to a cast iron block with a steel bolt. You might want to consider attaching the strap to the exhaust bracket itself if it has any existing holes or bolts.

Jack E/NJ
 
On my '40, I have a braided strap from the positive battery terminal to the firewall, and another braided strap from the firewall to one of the transmission mounting bolts.
 
It sounds like you are trying to be factory correct if so , go by the early V-8 club guide lines. That being said the best thing to do is somewhere out of sight ground the body to the engine via the bolts on the transmission and ground the battery to the engine via a bolt at the rear of engine possibly the back of the manifold or rear of the head. Grounding is very important to any electrical system. When I put any electrical connections together I use diletric compound at all connections and also use those star washers with clean areas where they are to make contact to the block or body, good connections are a MUST. All my old Fords work and start very good with 6v the way they were made from the factory.
 
Something I was surprised to learn recently is that dielectric grease does not conduct electricity:

Dielectric grease is a nonconductive grease. Because it is nonconductive it does not enhance the flow electrical current. Electrical conductors should not be coated with dielectric grease prior to being mated.

This from Wikipedia. A better compound to use in these ground connection areas is carbon conductive grease, that you can find at an electronics store. I use this at all ground connections, on the starter bolts, battery leads, and so forth. But if you use it, be careful to use it sparingly, because you don't want it migrating to areas where you don't want it -- like starter commutator, brushes and so on.
 
OLDDAD; I have always been aware of the face that diletric compound it is not a conductor. It keep's out the corrosion factor. It is used on many of the newer vehicles on the road with high and low voltage connections. I have been using it for about twenty years. Works very good on your trailer plug just fill the cavity with it and insert the plug don,t worry you will get a good connection. Also use it on battery connections they never get all full of corrosion. It would not hurt to use a conductor on block and fire wall connections but do not use it on other types of connections it would cause problems. GMHO Frank pkny
 
Certainly works to prevent corrosion, Frank, and I meant no criticism of your usage. I just prefer to use a conductive compound, with the caveats I mentioned. Sparingly, and where it won't migrate.
 
Old Dad no offense taken, Years ago an old mechanic made me put heavy bearing grease on all the new battery connections. It stops corrosion, I still do it to this day. You still get good conduction lead to lead. He said in WW1 they used it on all battery conections in airplans and trucks. He claimed they still did it in WW11. I apply it to the bottom of the post and to the bottom of the connector apply the connector tighten and then smear on the ballance of areas not already covered. [I sometimes use diletric compound also in this endever]. Last week I replaced the battery on my Ford tractor. It was eight years old and the connection looked like it was done the week before. The grease gets dirty but the connection was perfect. No corrosion whatsoever.
 
While we are at grounding, be sure the back of your generator mounting arm is clean and that of the intake manifold face. To be sure I ground the gen. case to a intake stud. Also the starter has a small steel piece for grounding. This little piece always goes missing.
Clem
 
What Clem means here is the small bracket from the starter to block it helps ground but also supports the starter.
 
From the picture on page 5-15 of The 1937 Ford Book (I don't have my 38-39 book with me at the moment) the body to engine ground strap goes from the bolt below and to the center of the car from the starter solenoid to the bottom rear head stud. I think this is correct for 38 also. To be sure refer to the 38-39 book.
 
This conductive grease concept was new to me, having used dielectric grease, red battery terminal grease, or vaseline for years. I discovered this when I bought a rebuilt starter from Vern Davidson (970-683-0178), who included an exhaustive installation guide (didn't think there was much to say about two bolts and a cable) with his beautifully rebuilt starter. He mentioned using OX-GARD, and recommended using it on the starter bolts, as this provides the best ground contact to the commutator end. He recommends cleaning each section of the starter of any paint or rust, and using the (often missing) front starter support bracket, which also is a good ground point to the block. I did a little research, as Old Henry did, and decided it made sense to me. Couldn't find OX-GARD at the local hardware store, but found the carbon conductive grease at an electronics store, so I used that. Spins over like a top, but of course it should anyway with a rebuilt starter and a brand new battery. I'd be curious if it would make any difference in a tired starter/older battery situation.

Anyway, glad you took no offense Frank. Now I don't have to drive the '40 to Poughkeepsie for a starter spinoff -- dielectric vs. carbon conductive grease!
 
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