6 Voltage

[John T]

Got the new (heavy) ground cable and an oversize tractor battery in the car but it is slow cranking. Apparently that is just a characteristic of an automatic transmission equipped car on six volts.

Ifffffffff you have a good heavy duty adequate high CCA battery ?? fully charged,,, perfect low resistance cables grounds and connections ??,,,a good low resistance starter switch/solenoid ??,,,,,,,but still slow cranking,, it could be the fault of the starter motor or for whatever reason ?? the engine is just hard to crank.. That being said having owned countless 6 volt cars trucks n tractors over 50 years, they were in general NOT known to be super fast crankers lol

John T

 

[rusty6]

Ifffffffff you have a good heavy duty adequate high CCA battery ?? fully charged,,, perfect low resistance cables grounds and connections ??,,,a good low resistance starter switch/solenoid ??,,,,,,,but still slow cranking,, it could be the fault of the starter motor or for whatever reason ?? the engine is just hard to crank.. That being said having owned countless 6 volt cars trucks n tractors over 50 years, they were in general NOT known to be super fast crankers lol

John T

There is a noticeable difference in cranking speed between cars with the standard transmission and the automatics. My 39 Deluxe with six volts sounds like it cranks twice as fast on six volts as the 52 Mercomatic. Always been that way.

 

[John T]

There is a noticeable difference in cranking speed between cars with the standard transmission and the automatics. My 39 Deluxe with six volts sounds like it cranks twice as fast on six volts as the 52 Mercomatic. Always been that way.

A torque converter even if out of drive yet its still turning, especially if the oil is cold, could cause a drag ??

John T NOT an auto tranny expert so no warranty

 

[buickanddeere]

Biggest trouble I’ve had with 6 volt (tractor) is poor grounds to chassis,corrosion on the cables. Oh too small a battery

I agree . A voltmeter should be placed across every connection/bond . Voltage measured while cranking .

 

[rusty6]

A torque converter even if out of drive yet its still turning, especially if the oil is cold, could cause a drag ??

John T NOT an auto tranny expert so no warranty

Yes, and I expect that is why Ford put the lower geared starter drive in the automatic equipped cars.

 

[westga]

I agree . A voltmeter should be placed across every connection/bond . Voltage measured while cranking .

On early chevys the ground went just to the fire wall. It would help if this is the case on this Merc to go to the engine block.

 

[rusty6]

On early chevys the ground went just to the fire wall. It would help if this is the case on this Merc to go to the engine block.

Yes, ground cable is under a bolt on the intake manifold so that should be good.

 

[kencombs]

A torque converter even if out of drive yet its still turning, especially if the oil is cold, could cause a drag ??

John T NOT an auto tranny expert so no warranty

Not only is the torque converter turning but the tangs on the back of it are turning the front pump in the transmission. Fair amount of load there too.

 

[Janicholson]

He would be better served to observe the voltage while cranking the engine. That would be a true load test under normal conditions. I don't trust those analogy gauges I always back the up with a DVOM.

The video did show it cranking at ~5 volts and wiggling as the engine came up on compression. I would probably put 10 40 oil in it to see if it made a difference. Jim

 

[buickanddeere]

Yes, ground cable is under a bolt on the intake manifold so that should be good.

Ground cable on a starter mounting bolt is an even safer bet . Although moving away from the firewall is a good plan and eliminates many potential problems .

Once upon a time we had a Deere 4230 that appeared to have a clean ground contract onto the engine block . Had to buff everything to a shine and it took several attempts to eliminate the voltage drop.

 

[560Dennis]

How many volts at the coil while cranking ? Just wondering ? Good information for everyone also .