1953 Buick special slow cranking

[Skolfield]

My 1953 Buick special wont crank fast enough with a 6 volt battery. I had it running with a 12 volt battery but I can't use that one permanently without adding resistors. its not the starter or solenoid both are refurbished.  Thanks for any help

[rocketraider]

What gage wire are your battery cables? 0 or 00 are good for 6v system (+) cables, and I think most all GM vehicles back then were using braided flat cable ground straps from battery (-) to the car's frame or engine block.

 

Using modern, smaller gage 12v battery cables on 6 or 8 volt systems can cause problems like you're having.

[Skolfield]

I am using 00 gauge battery cables on both positive and negative terminals. 

[37_Roadmaster_C]

Ok, a couple of questions... First, 6 volt cars DO NOT crank fast. If you are expecting it to crank like a more modern car, it will not! A slow crank is just fine if the engine is tuned properly. It will start, it just seems wrong until you get used to it. Now with that said, check ALL connections. They need to be clean, rust free and tight! Another thing you might try is to add a ground cable between the bolt that the battery grounds to and the starter or engine block. Some have had trouble with the engine ground without a bonding cable.

[195354]

Clean everything like Robin suggested check every ground surface and cable. I am not sure how this grounds, I would suspect a weaved cable to the block or frame then does the starter ground with a short cable to the frame or block. I personally have fought problems with  starting systems and lost sight of a good grounding system. 12 volt or 6 volt systems all need a sound ground this will affect cranking and possibly give you a voltage drop for the ignition.

I just had a cable issue at work, the cables looked good ohm checked  out good but the unit would crank slow intermittently.  I added jumper cables from the battery to the starter and found the problem. If possible try this if they will fit, home run jumper cables  from battery to starter fully charged battery and see how it cranks. You need the larger cables that Robin suggested the lower voltage needs larger cables. 

 

 I would check voltage at the coil before and while cranking possibly give the points a file treatment if needed. I checked the service manual and did not see a spec for cranking speed, I would think its in a spec that I have not found. Other things that you could check are coil and condenser and ground at the distributor and check your plugs. 

 

Hows the floor repair coming along these can be time consuming, like to see how the braces are working out. 

 

Steve  

 

 

 

 

[60FlatTop]

I would check the action of the breaker plate in the distributor to be sure it wasn't sticking and giving you too much advance on start up. Just push against the condenser with your finger to rotate it. Release and it should snap right back. If it doesn't there is a cork lubrication pad that wicks oil from the lubrication pipe. You could try feeding some fresh oil but taking the plate out for lube would be better.

[Pete O]

I had the same problem of slow cranking, particularly when the engine was hot.  After a lot of trial and error, I found that the starter itself was binding.  The bushings were too tight on the armature shaft.  I could not spin the armature by hand.  Took it apart and reamed the bushings and that fixed it.

[Skolfield]

Tried everything mentioned in this thread. Car still cranks slow unless spark plugs are out. The generator is not hooked up to the car. didn't think it would make a difference but I am running out of ideas. Is the generator necessary for starting?

[old-tank]

On 12/12/2021 at 12:21 PM, Skolfield said:

its not the starter or solenoid both are refurbished.

We have all had rebuilt/refurbished/new parts that were worse than the parts they replaced.  Try a different starter.

[southpaw]

Eliminate advanced ignition by removing coil hi voltage wire from center of distributor and grounding to block. If it cranks correctly now your timing is too advanced. No change, you're left with weak battery or weak starter. Remember these cars started just fine back in the day. There is a problem you have not found YET. Triple check your grounds. With auto electrical systems it's always the ground.  As mentioned above they did not crank fast. Get busy spring is almost here.

 

Best of luck,

Jim

[PONTIAC1953]

7 hours ago, Skolfield said:

Tried everything mentioned in this thread. Car still cranks slow unless spark plugs are out. The generator is not hooked up to the car. didn't think it would make a difference but I am running out of ideas. Is the generator necessary for starting?

no it isn't/

[60FlatTop]

If I was stuck and not finding a problem I would pull the pin from the solenoid on the arm that pulls the Bendix in. That way the engine won't crank but you have a load on the starting circuit. Then us a VOM to measure for voltage drop across each node and terminal starting between the battery post and battery clamp and work your way through the whole system. Look for zero voltage drop at each connection.

[Skolfield]

The starter is getting 5.6 volts when cranking. Is it possible the previous owner put an armature in designed for a 12v starter.

[EmTee]

If I understand what you're saying, there's about a 1 Volt drop between the battery and the starter (assuming a full charge battery voltage of 6.6 V).  If so, that seems reasonable.

[195354]

I would Pull the starter out and have it checked out or find another one for testing. I would think it is possible it has a 12volt field winding or armature.  I have an electric shop close by they never ask if it is 12 volt or 6 volt, I bring it up when dropping things off for repair.  Just to be sure I don't get the wrong parts installed. 

One thing you could  try if you have the cables is hook short cables direct to the stater and use a starter bumper. This will bypass everything, if it cranks over like it should start back tracking 

Good luck 

Steve 

[Skolfield]

At this point I am fairly certain that the engine is partially seized. I am getting oil pressure but there is sludge in the valve cover. Might try putting some marvel mystery oil in the crank case.

[Larry Schramm]

On 4/3/2022 at 8:09 PM, EmTee said:

If I understand what you're saying, there's about a 1 Volt drop between the battery and the starter (assuming a full charge battery voltage of 6.6 V).  If so, that seems reasonable.

 

I would go back and check/change the cables to larger wire.  Possibly 0000/ 4. One volt drop seems like a lot.

 

Could be a bad battery.  Have you had the battery load tested? 

 

If so and you change to larger cables, you can solder the ends which will give you a better connection between the cables and the terminals where there could be a voltage drop. 

 

Just my thoughts.