Hi Joe. I looked at the starter box that came from KEP and I have the same numbers as yours. So we have the same starter. I tried all the things people said here before but it just didnt crank my engine. If you think your starter is defective, then you can borrow mine , just pay for shipping (95757). Just like you, I looked everywhere and the only one that is similar to our starter was from mean green. Its 2.5 KW. Its Model MG16674. www.mean-green.com. I am not affiliated with them. Just trying to help you. Good luck.
Joe’s AP MK1 Gt40 build
- Thread starter Buttinz
- Start date
Battery is literally right next to motor. Is a braile battery B2015 series 1067 CA. All wire feeds&grounds are 4g and 10g ignition from switch to solenoid
I would try hooking some jumper cables or a bigger cable along with the regular cable from the battery to the starter to see if it makes a difference. I think 4ga wire is only good for about 60 amps.
Davidmgbv8
Supporter
I agree your wire is too small remember an electric motor under starting mode inrush current is far higher. I would be at a #2 or 1/0 ground to the block and a or a 2/0 positive wire to the starter.
For reference my Zero turn lawn mower had a #14 ground and a #10 positive, turned over slow and so I got a Battery disconnect and did everything in 6ga and you barely hit the key and the motor zings over and starts with about 3 rotations.
For reference my Zero turn lawn mower had a #14 ground and a #10 positive, turned over slow and so I got a Battery disconnect and did everything in 6ga and you barely hit the key and the motor zings over and starts with about 3 rotations.
4 ga wire is good for 100A on a short run. Kind of marginal for a 427.
If you're only seeing 7.2V at the starter, you have too much loss. Could be-
Poor connections
Weak battery
Weak or undersized or too long wires
Soggy solenoid
Poor crimps on terminal ends
If you're only getting 7.2V to the motor, that's not a fault of the motor. A stalled brush motor acts like a big ass resistor, and if you're only feeding it 70% of the minimum voltage, you're only getting 70% of its potential torque.
I say 70 because sagging to 10-11V would be acceptable and expected. 7 is unacceptable.
It very possible could be a combination of 2-3 of the above, and fixing one will make it work... this time. But ready to fail.
But I would still say a 1KW (crappy AC Delco reman) starter isn't enough. I would at least get one of the new aftermarket high output ones that cross reference to yours. One that I linked to above claimed to have a 1.4KW motor. That's 40% more. Another one I saw that looked like the same snout and was a toyota claimed a 1.7KW motor. But those may be chinese watts that will leave you hungry in 2 hrs.
You can put your volt meter from the positive batter terminal to the wire between the solenoid and starter motor. Not cranking you should see 13V. When cranking you need to see less than .7V or so. This is the loss on the positive side.
Then do the same for the grounds. meter between the neg terminal on the bat and started case and see what you have when you hit the starter. Should be less than the positive.
If you're only seeing 7.2V at the starter, you have too much loss. Could be-
Poor connections
Weak battery
Weak or undersized or too long wires
Soggy solenoid
Poor crimps on terminal ends
If you're only getting 7.2V to the motor, that's not a fault of the motor. A stalled brush motor acts like a big ass resistor, and if you're only feeding it 70% of the minimum voltage, you're only getting 70% of its potential torque.
I say 70 because sagging to 10-11V would be acceptable and expected. 7 is unacceptable.
It very possible could be a combination of 2-3 of the above, and fixing one will make it work... this time. But ready to fail.
But I would still say a 1KW (crappy AC Delco reman) starter isn't enough. I would at least get one of the new aftermarket high output ones that cross reference to yours. One that I linked to above claimed to have a 1.4KW motor. That's 40% more. Another one I saw that looked like the same snout and was a toyota claimed a 1.7KW motor. But those may be chinese watts that will leave you hungry in 2 hrs.
You can put your volt meter from the positive batter terminal to the wire between the solenoid and starter motor. Not cranking you should see 13V. When cranking you need to see less than .7V or so. This is the loss on the positive side.
Then do the same for the grounds. meter between the neg terminal on the bat and started case and see what you have when you hit the starter. Should be less than the positive.
On the battery post at starter I have 12V, on solenoid (ign)of starter its 7v during cranking. If I pull wire of starter and crank I have 12v. All grounds are good. So your thinking the 4g is good enough? I know I did at first lol.the acdelco supplied starter is 1.4kw
Looking forward to you getting this figured out so I don't have to deal with it! It seems like it is something that Chris has probably dealt with before, since I think he uses the Porsche transaxles often.
I have a 570 horse LS3 in my 69 Firebird with the Optima in the trunk. It has an AC Delco starter as well. I used 1-0 gauge for the positive and everything has been working ok.
I have a 570 horse LS3 in my 69 Firebird with the Optima in the trunk. It has an AC Delco starter as well. I used 1-0 gauge for the positive and everything has been working ok.
Not sure I'm following what you've measured, but 7V across the motor is not enough.
Do you have a battery cut off switch in the circuit? That could also be a loss point.
If you're losing more than 1 volt in the wire from the battery to the starter, it's not heavy enough.
Are you running the old Ford style separate solenoid or hot wired to the solenoid on the starter?
Do you have a battery cut off switch in the circuit? That could also be a loss point.
If you're losing more than 1 volt in the wire from the battery to the starter, it's not heavy enough.
Are you running the old Ford style separate solenoid or hot wired to the solenoid on the starter?
Davidmgbv8
Supporter
If I did my math right, That starter is drawing 158 amps. So if the starter is good your wire was undersized for the application
I typically use 1g cable on runs longer than 24” as there is too much loss and amps too high at starter motor with smaller cables.
Try using an automobile jumper cable from the negative battery terminal to the block close by the starter. This will augment your ground connection. You can do similar with the positive cable from battery to the starter post.
Try using an automobile jumper cable from the negative battery terminal to the block close by the starter. This will augment your ground connection. You can do similar with the positive cable from battery to the starter post.
Yes I have battery kill switch.no remote starter solenoid I’m directly to starter solenoid. New cables came today I’m just waiting for terminal ends,still out for delivery smh. As you can see in pic it’s a big diff in size,hopefully solves problem.
I wouldn’t even know where to start on trying to do that math lol. Swapping all out with 1/0
Davidmgbv8
Supporter
Congratulation! sounds awsome
Glad you got it figured out! it must have been the starter battery cable?
I would be watching your AFR closely. if it climbs to 35 and becomes unresponsive, check for an exhaust leak....ask me how I know. Getting the exhaust to seal up for the O2 sensor is the main concern I have with the Bundle of Snakes type of exhaust and running fuel injection.
I would be watching your AFR closely. if it climbs to 35 and becomes unresponsive, check for an exhaust leak....ask me how I know. Getting the exhaust to seal up for the O2 sensor is the main concern I have with the Bundle of Snakes type of exhaust and running fuel injection.
Swapped out main cables to 1/0 gauge and still had issue.bought another new starter and it fired right up
