Undersized cables ?

[p24-1953]

I have a slow crank condition on the 40' but I thought yall could help.  Symptoms:

1) Extremely slow cranking even thought I am using a 1000ca optima battery ( new)

2) battery cables get very hot after starting.

 

It will start it just takes 5 or 10 secs of cranking.  Timing is set to 4btdc ( set it to 0 and made no difference)

The battery is well grounded.

Bypassed the Selinoid by touching cables together and still supper slow.

 

The cables look to be the right size, but not sure.  Are all signs leading to undersized battery cables?

 

[greg g]

Should be zero gauge cables.  Some times the rear armature bushings wears oval, this allows the armature to drag against thefield coils when cranking. It's fixable but do the cables first.make sure all connections are clean and tight and grounds are good. 

[keithb7]

Hot cables is a clue. Too many amps trying to be shoved through too small of a path. For example. Good vs Bad.

Could be part of your problem. There are other factors too. Field windings? Armature windings condition? Brushes? Etc...

 

 

Edited August 18, 2020 by keithb7

[Plymouthy Adams]

as stated...too small a cable....not good....dragging starter due to worn/elongated rear bushing...and voltage drops due to poor connections not only where they bolt at the connectors...but the internals of the cables themselves may be poorly made also...do a voltage drop test....read a good white paper on testing voltage drops....not hard to do but would be a long write up for anyone to step by step this.

[Sam Buchanan]

Proper size cables are huge and easily sourced online:

 

Edited August 18, 2020 by Sam Buchanan

[Sniper]

Assuming the 40 has the original 6v system, which the OP doesn't mention.  Then cable size is important.  When I got the 51 it was a 6v system and the PO's hack mechanic put 12v size cables on it.  It had no problem starting though, so I would also look for any other issues that might be making the engine harder to start than it should be.  I can turn the engine over by hand just by rotating the fan.  If the engine's too tight then battery cables won;t matter. 

 

 

[Jerry Roberts]

The O P mentioned he has an Optima with 1000 CCA .  Probably he has a 12 volt system as when I look up the Optima it doesn't show a battery in 6 volt with 1000 CCA . 

[greg g]

Should have said his setup was not stock. Be nice to have that info before suggesting long distance trouble shooting...

[p24-1953]

1 hour ago, Jerry Roberts said:

The O P mentioned he has an Optima with 1000 CCA .  Probably he has a 12 volt system as when I look up the Optima it doesn't show a battery in 6 volt with 1000 CCA . 

Sorry its 800 cca 1000 cranking amps and yes it is 6v.

[p24-1953]

34 minutes ago, greg g said:

Should have said his setup was not stock. Be nice to have that info before suggesting long distance trouble shooting...

greg, if it was not stock I would have said so.  I am running a 6v optima.  It is basicly in a preserved state as it sat in 65.  I have rewired it and switched to disc brakes.  Is that stock enough?

[greg g]

Was reacting to Jerry's post.

[lepic56]

Because of this topic and many others before..  I did replaced my 12 volts cables (3) with bigger 6 volts cable from rock auto,,   what a difference when starting the engine so much faster.. thank you all for the good advises..  ?

[p24-1953]

Got new 2/0 cables last night so I will put them on and let everyone know how it goes.