72downunder

Hey all,

completed a rebuild of our '72 350, which is now a slightly worked 383, compression is high, and while it used to start first time everytime. Now it sometimes starts first go then at other times just cranks over. We've been away fro 2 weeks, its been cold, I've had a trickle charger on the battery, and tried to start it this morning. Wouldn't go, primed the carb, tiny bit of throttle as always and then acoup[le of very slow wrrrrs from the starter and thats it. Thought I might have flooded it, so waited 5 minutes with the charger on, same thing. Had a look at the starter, all the wires are connected tight, 5 minutes later tried again and roared into life first go. Starter is original

Is there a problem with these starter motors, could it be wearing, or something else maybe? Its certainly getting power and spark, the starter sometimes just seems to not want to turn, yet other times its fine

Cooter Tech

How old is the battery? I have had batteries with a bad cell do the same thing, battery maintainer even indicated a full charge. Check your grounds and starter connections.

ntfday

I would suggest having the battery load tested. That should determine whether it has a weak/bad cell.
Then pull the starter and disassemble. It should have thrust washers at each end so be careful not to loose them. Clean the commutator with fine emery cloth and ensure the brushes aren't too badly worn and if so replace them. Put a tad bit of grease on both ends of the armature and reassemble.
The solenoid is probably your problem and if you disassemble it you will probably find that the copper clad disc is badly burnt. It can be cleaned but if it's badly burnt I'd replace it. The solenoid is the weak link in a GM starter and generally fails long before the the starter motor wears out.

72downunder

Battery is only one year old, last time I was at the mechanics they tested the battery and it appeared fine, about 1 month ago. So maybe it is the solenoid then, seeing it happens sometimes and not at others.

showing fully charged this morning, took a few goes to get it going in 10'c temp same problem starter clicks over 1 -2 times very slowly then nothing, then started 3rd time straight off the bat. went for a half hour drive, had a coffee somewhere, so half hour later started fine with starter doing its normal faster turn over. Stopped short time later and bumped the hazzard lights on for 5 minutes. came out and the battery didn't have enough charge get the starter going more than once.

Would hazards running for that short amount of time run down the battery that much?

ntfday

Yes, if the battery has a weak cell and I've had a couple of batteries develop weak a cell within the first two years of life. Have it load tested.

Cooter Tech

You might have bought the battery a year ago, but it could have sat in the store for two or more years. As soon as they put acid in the battery, it starts to degrade. Your symptoms sound like a failing battery that can’t hold a charge or get fully charged. Are batteries in your country date coded?

72downunder

Cooter you may be onto something there. When we got the engine rebuilt it also went in for some accident repair which by the time insurance came through it was six months, so it had just sat at the shop wearing the battery down I guess.

Took it to a shop we have here called battery world, deals in all sorts of battery for cars truck etc, explained the situation and they tested it. Looks like voltage was good but cranking power was down by half. Bought a new battery, so far its started first go and cranked over faster and more immediately than described in the problem.

Thanks for your help guys.

Cooter Tech

Good! An alternator can also destroy a battery by overcharging it. It can boil the acid out, but you will smell the odor and the battery will be extremely hot. Don’t use a trickle charger to keep the battery at full strength. I suggest a battery maintainer or disconnect the battery if it sits for an extended period of time.