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Trifive Automotive Electrical Wiring Expert
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Stock had a ground strap from the battery to the firewall. ....http://www.trifive.com/garage/55%20Chevy%20Assembly%20Manual/12-11.gif http://www.trifive.com/garage/55%20Chevy%20Assembly%20Manual/12-14.gif and another from the starter motor to the body. .... That's not a good place IMO. Run the cable from the battery directly to the starter mount bolt to any of the bellhouseing bolts on the engine. That provides a direct path for the high current for the starter. Then run a ground from the engine to the body. Clean the area under the cable of paint, to provide a good connection.
 

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The oem way of doing things my have worked for a 6 banger with points, but it is not optimum for a more modern system. Ground the battery to a clean spot on bellhousing for best result as stated.
 

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I have my battery in the trunk. I ran a ground to the trunk floor and on to the frame beneath it. I also ran a ground from the fire wall to the frame and the engine. It works so far but it's only been running for three days.
Jim
 

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Good grounds

Good grounds are absolutely vital for those of you running shifters with cables. I used to work part time in a speed shop. and many cables had to be replaced as owners didn't take care of or removed the factory grounds as they were in the way of headers. The end result is the cable ends up being the ground and welds operating wire to case. :anim_25:
 

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To stop electrolysis you should create a triangle - batt to block (bell bolt is good), block to frame, frame to batt. Especialy if you have any aluminum wet parts (parts that see contact with coolant) such as heads, intake manifold, waterpump or therm housing.
 

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There's really no need to ground the frame at all unless some of your accessories are grounded there, or you're using the frame as a ground path for a remote battery to the engine. The body contains all the grounds you need for lights, etc.
 

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There's really no need to ground the frame at all unless some of your accessories are grounded there, or you're using the frame as a ground path for a remote battery to the engine. The body contains all the grounds you need for lights, etc.
Not for performance - there is also no need to zinc boats either they will still float and run. But check out a on prop from a zinced boat and a prop from that the owner says the "you don't need" where they both have the same hrs and you will see the difference.

but after very few years look inside the the water passages of your aluminum head and intakes. See all them places where the aluminum dissapeared and left cavities?? Yep? Comes back to no triangle every time ya see it.

NOT because of the batteries current as in "using your frame to ground accesories" but because of the difference between the batteries current flow through the block and the static electricity from the coolant flow. the tringle eliminates the static by ensuring the water is part of the entire vehicles ground!
 

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Not for performance - there is also no need to zinc boats either they will still float and run. But check out a on prop from a zinced boat and a prop from that the owner says the "you don't need" where they both have the same hrs and you will see the difference.

but after very few years look inside the the water passages of your aluminum head and intakes. See all them places where the aluminum dissapeared and left cavities?? Yep? Comes back to no triangle every time ya see it.

NOT because of the batteries current as in "using your frame to ground accesories" but because of the difference between the batteries current flow through the block and the static electricity from the coolant flow. the tringle eliminates the static by ensuring the water is part of the entire vehicles ground!
The frame is electically insulated from the body due to the rubber body mounts and engine/tranny mounts. I don't see any way that any "electrolysis" can occur due to an ungrounded frame, and I don't see how any "triangle" of grounds can prevent it if it even COULD occur. Old wives tales, and hocus pocus, imo. :rolleyes:

"Static electricity" from coolant flow? No offense, but....:sign0020:

Sorry, I couldn't help it. :D

I maintain that the frame doesn't need to be grounded at all, and that it will cause no problems if it isn't. All you have to do is use the body for ground. I'm not aware of any place the factory grounded the frame on these cars. I think all the grounds were made to the body and to the engine. That's all you need.
 

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Coolant voltage??

I recall an article some time ago that stated you should dump your coolant when its voltage read .5 on a digital voltmeter to prevent corrosion from going wild. I think this indicates an acidic level. :anim_25:
 

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Actually its not static electricity but electro-chemically generated current due to dissimilar metals aluminum , cast iron in contact with coolant that provides the electrolyte and the aluminum is eroded by it. Use sacrifical anodes in the coolant system and that will help prevent damage to the aluminum parts.

Regards, Robert
 

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"Static electricity" from coolant flow? No offense, but....:sign0020:

Sorry, I couldn't help it. :D
none taken - and I am laughing as well. My brain was thinking "electro static current" yet my fingers typed "static electricity". lol - although interestgly enough static electricity does play a part! See link below!

One thing to clarify though - in the triangle I describe - frame ground and body ground interchange in terms - in other words the triangle can be stated as batt to frame/body, frame/body to engine block, engine block to batt. The goal is to make sure that the source of ground for all your electronics whether it's the body or the frame is carrying an equal ground as both the battery and block.

http://www.awrracing.com/media/electrolysis.pdf - refer to paragraph electrolysis facts.

http://www.cb7tuner.com/vbb/showthread.php?p=492835

http://www.search-autoparts.com/searchautoparts/article/articleDetail.jsp?id=154932

http://www.lcengineering.com/Inst/1021024_1021027.htm (read the ground strap warning re warranty thats the block to body/frame leg they are requiring.

and finally:
http://www.pelicanparts.com/bmw/techarticles/E36-Coolant_Flush/E36-Coolant-Flush.htm - the discussion there explains it well - and the accompanying photo show MINIMAL damage compared to some I have spent hours huntched over a tig welder repairing.

no in 55-57 they did not have a ground triangle - nor did they have aluminum heads, blocks, radiators or on board electronics, etc.

You can lead a horse to water.... and you can take his money when he learns the hard way.
 

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Actually its not static electricity but electro-chemically generated current due to dissimilar metals aluminum , cast iron in contact with coolant that provides the electrolyte and the aluminum is eroded by it. Use sacrifical anodes in the coolant system and that will help prevent damage to the aluminum parts.

Regards, Robert
Thanks Robert, read above post - lmao at myself. static electricity in water. duh...electrostatic!

sacrificial anodes (much like the rather expensive zincs on a boat) do prevent -but seem more expensive to install and replace regularly (annually in marine maintenace) than just eliminating the current flow issues with straps that should last 20 years. Just my thoughts and certainly the way I would (and do) protect my investment.
 

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I recall an article some time ago that stated you should dump your coolant when its voltage read .5 on a digital voltmeter to prevent corrosion from going wild. I think this indicates an acidic level. :anim_25:
How in the world do you get .5V in your coolant? Where is this measured?

I know galvanic or electrolytic corrosion can take place between dissimilar metals with the presence of an electrolyte (like sea water) but I don't understand where the electrolyte is in a cooling system. Does the coolant become contaminated with ions of some sort? I can't imagine anything causing a .5V differential. I can see a few millivolts....maybe. :confused0006:
 

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I bought a 55 with a 6 cyl last winter. It would do NOTHING when I turned the key. Although I was told this car was running but the battery was shot, I found the lower braided ground cable hanging. When I cleaned it and bolted it to the starter, it turned over. :confused0006: I'll never buy one at a RUNNING price without hearing it run 1st. I also do not usually ground the chassis unless I'm running an electric fuel pump mounted to it or mounting a battery in the trunk.
 

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How in the world do you get .5V in your coolant? Where is this measured?

I know galvanic or electrolytic corrosion can take place between dissimilar metals with the presence of an electrolyte (like sea water) but I don't understand where the electrolyte is in a cooling system. Does the coolant become contaminated with ions of some sort? I can't imagine anything causing a .5V differential. I can see a few millivolts....maybe. :confused0006:

From the last link I provided:

How can you test for electrolysis? Other than actually seeing visible signs of erosion, you can perform a current flow test. Connect the negative terminal of a voltmeter to the chassis ground. Test for adequate continuity by touching another point on the chassis - the resistance should be near to zero. With the engine cold and running, submerge the positive probe into the coolant tank, making sure that the probe does not touch any metal parts. The voltage should be less than .10 volts. If not, methodically turn off or unplug each electrical accessory until the reading reads below .10 volts. Have an assistant switch accessories (like the A/C compressor, heater blower, etc.) while you measure the voltage.
 

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Dissimmilar metals are the base cause - eltro-static current is the accelerant.

From experience - Ford Tempo 1.8 engine. Know anyone who drives one? Go out and cut the braided line that runs from the back of the cylinder head to the firewall (as many mechanics do when they forget to hook it back up after a water pump change and) - everything will still work fine. So you are correct - you don't need that third ground - but you may want it because if you are lucky it will blow a head gasket in 6 months and the machine shop will be able to grind out the bad and tig in some new alumiminum around the water ports at the head gasket surfaces and remill. If you are unlucky the head gasket will hang in there by a thread and not blow - right away. By the time it does the head will look like swiss cheese in the water jackets and there will be no saving it. In this worst case screwdriver can often be pushed from the upper oil returns, the exhaust port and even the outside of the cyl head above the spark plug holes right into the water jacket. We got at least 3 1.8, a couple of 3.8 chevys and a one or two other models PER WEEK for these types of repairs (coming from dealers as well as reputable mechanic shops) - the common denominator when showing the problem and discussing the solution with our clients was the ground from engine to firewall.

Ford cable from the factory is a two cable connect at batt serving both frame\body and engine - the triangle is completed by the braided wire from head to firewall.

Now I will agree with ya that if all ya got is points type distrib and a radio (very stock) with all cast iron block having the extra ground is really overkill for nada. But if you are running a computer, A\C, high end radio, electric fuel pump, power windows etc etc and have aluminum - why argue with the engineers that solved most of the longevity problems back the 80"s by using the triangle? I ain't making this stuff up - I am simply sharing what I was taught to explain and solve what I was seeing! Even without all that upgrade stuff on my 57 - if it means my baby will last longer - I'll do it! Who cares if it outlives me and my grandkids? Somday they may have the only one left and ya'll non hocus pocus ers will NOT be the ones being coveted! Its a five dollar cable!

Whats the difference between old cars and new cars? The new cars have a bigger pile of leftover parts after the mechanic gets done removing the "uneeded" ones.:sign0020:
 
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