Slow Crank, No Start When Warm

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What battery?

I still believe your cable size is part of it.

Electric fans?
 
Just your basic Napa battery, 34 group, 690 CCA. 2 guage cables running to and from the terminals. Yes I have dual electric rad fans but they're on a toggle switch so when I'm trying to heat it up(or test like I just did) I don't turn them on.
 
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To make sure we are on the same page, are you sure they are not 2/0 sized wires?

2 gauge is much smaller then 2/0.
 
After you try cranking it when hot, go feel your ground cable at the battery
 

2 AWG Wire​

2 AWG wire has a diameter of 0.2576 inches (6.54 mm) and is commonly used for applications that require high ampacity, such as industrial equipment, heavy machinery, and large appliances. It has an ampacity of 115 amps at 60°C (140°F), 130 amps at 75°C (167°F), and 150 amps at 90°C (194°F).

2/0 AWG Wire​

2/0 AWG wire has a diameter of 0.3648 inches (9.27 mm) and is larger than 2 AWG wire. This wire is commonly used in power distribution and transmission applications, as well as for grounding and bonding. It has an ampacity of 135 amps at 60°C (140°F), 155 amps at 75°C (167°F), and 180 amps at 90°C (194°F).

Differences Between 2 AWG and 2/0 AWG Wires​

Attribute2 AWG Wire2/0 AWG Wire
Diameter0.2576 inches (6.54 mm)0.3648 inches (9.27 mm)
Ampacity (60°C)115 amps135 amps
Ampacity (75°C)130 amps155 amps
Ampacity (90°C)150 amps180 amps
Resistance (Ohms/1000ft)0.6240.393
The main differences between 2 AWG and 2/0 AWG wires are their diameter, ampacity, and resistance. 2/0 AWG wire is larger in diameter than 2 AWG wire and has a higher ampacity. Additionally, 2/0 AWG wire has lower resistance than 2 AWG wire.
 
I might end up needing to run larger cable than 2/0 then as I have a high output alternator putting out around 215 amps
 
I might end up needing to run larger cable than 2/0 then as I have a high output alternator putting out around 215 amps
those are for 115 volts. 2/0 wire good for 500 amps at 12 V. Or so....
 
Alright, ill look into getting some 2/0 welding cable. I'll be sure to post weather or not that was the problem. Thanks
 
Alright, ill look into getting some 2/0 welding cable. I'll be sure to post weather or not that was the problem
You might be able to get additional 2AWG wire and double up the runs! Might be cheaper than 2/0 wire.

Either way you can use both sets of wire in the end.

The cross section area of 2x 2AWG is about .098 in sq

The cross section area of 2/0 is about 0.102 in sq
 

2 AWG Wire​

2 AWG wire has a diameter of 0.2576 inches (6.54 mm) and is commonly used for applications that require high ampacity, such as industrial equipment, heavy machinery, and large appliances. It has an ampacity of 115 amps at 60°C (140°F), 130 amps at 75°C (167°F), and 150 amps at 90°C (194°F).

2/0 AWG Wire​

2/0 AWG wire has a diameter of 0.3648 inches (9.27 mm) and is larger than 2 AWG wire. This wire is commonly used in power distribution and transmission applications, as well as for grounding and bonding. It has an ampacity of 135 amps at 60°C (140°F), 155 amps at 75°C (167°F), and 180 amps at 90°C (194°F).

Differences Between 2 AWG and 2/0 AWG Wires​

Attribute2 AWG Wire2/0 AWG Wire
Diameter0.2576 inches (6.54 mm)0.3648 inches (9.27 mm)
Ampacity (60°C)115 amps135 amps
Ampacity (75°C)130 amps155 amps
Ampacity (90°C)150 amps180 amps
Resistance (Ohms/1000ft)0.6240.393
The main differences between 2 AWG and 2/0 AWG wires are their diameter, ampacity, and resistance. 2/0 AWG wire is larger in diameter than 2 AWG wire and has a higher ampacity. Additionally, 2/0 AWG wire has lower resistance than 2 AWG wire.
Tim where did you get that chart? There are all kinds of them, and "some disagreement" LOL. AC ampacity is not to be used for automotive. Also, FOOTAGE of the total wire matters

I'm not claiming this website is more accurate, but quite different results.......


To the OP............2/0 is considerably more capable than no2. As an example, wire size goes (smaller to larger) 10/ 8/ 6/ 4/ 2/ 1/ 0/ 00 or same as 2/0.
As an example, "old school" no4 was normally front mount 12V cable in most cars. Older 6V were commonly 1 ga.
 
[1] If you are running a grd cable from the starter [ block ] to the battery, that will be part of the problem. Too much resistance, which causes a power loss. You should use the body/chassis as the grd connection.
[2] I had a look at the TuffStuff website & two starters are shown for the SBM, a 'std' & a more powerful one for high output engines. Neither one has a HP rating [ post #14 ] , which makes me suspicious that are low HP. A high HP rating would be a plus for selling the product. The starter needs to produce a certain amount of HP to crank the engine. When hot, the res increases & HP output is decreased. This loss has to be factored into the choice of starter used. That is why there are 0.9hp starters &....3.2 hp starters.
[3] The TS starters are the Nippon Denso style, motor on top. Never found them as powerful as the Hitachi design, sol on top.
 
What I'm going to be saying I know as personal fact. My dad had a 1981 dodge pick up and he had issues with starting when the engine was warm and a charging issue as well. I replaced both battery cables, checked all wire connections for being clean and tight, only a temporary solution. I put on a starter for a 440 ( his truck had a 318 ) and it helped for a while and then one day while I was trying to figure it out I noticed a braided cable that was bolted to the firewall but the other end went no where so I decided to bolt the other end to the block and problem solved. So I decided to do some research on this and I discovered that a ground cable has to go from the battery to the block, and from the block to the firewall. I don't know if this was factory or not but it also had a cable going from the frame to the block. I don't know if this will be of any use for the OP, but I hope that maybe it will be of some help to someone else. Also I've seen both battery cables corrode inside the cable. No one told me this and I didn't hear about it from anyone, it's from personal experience.
 
Just checked for voltage drop, 12.61v at battery, 12.61v at alternator, and 12.60v at starter. Can't test while cranking as I'm alone
Then get a remote starter switch. Any auto parts store will have one cheap.
 
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