Thread: 350 trouble

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So I just bought an 88 comaro with a Chevy 350, obviously not the original motor, the car was running just fine. I drove it from a Bronx to Hackensack. Now when I go to start it it doesn’t crank it just makes the noise of an electric motor humming. The battery is charged but when I crawled underneath I found that the noise was definitely not coming from the starter. Btw I’m a little new to auto mechanics and this car is like a first project

It sounds as though your starter is failing. Disconnect the battery and make sure all the connections at the starter are tight and not oily or greasy. If it still does the same thing pull the starter and take it to your favorite auto parts store and they should be able to test it for you.

If you have some basic tools like a socket set and ratchet. See if you can get a socket to fit onto the bolt head in the center of the harmonic balancer, ( big pulley at the bottom front) see if the motor will turn in either direction - even just a short distance.

Just to prove the motor isn't stuck.

sure sounds like a bad starter solinoid.
Witch I always called a bendix..

Originally Posted by Stroker51

sure sounds like a bad starter solinoid.
Witch I always called a bendix..

The solenoid engages the starter motor electrically and mechanically drives the bendix to the rear to engage the flywheel/flexpalte. Two totally different animals.

If you have to get technical, there's no such thing as a bendex.thats the man's name that invented it, it's called a starter drive.

Originally Posted by Stroker51

If you have to get technical, there's no such thing as a bendex.thats the man's name that invented it, it's called a starter drive.

Then you damn well should know the difference. Bad information is as bad as no information, maybe worse.

And I damn well know my information is not bad.this sounds like one of them know it all bull shit sites. How stupid can you get about something simple as a starter

Originally Posted by Stroker51

And I damn well know my information is not bad.this sounds like one of them know it all bull shit sites. How stupid can you get about something simple as a starter

You're the only one spouting bullshit, a bendix and a solenoid are TWO different animals, period.

Welcome to CHR!

Let’s see if we can turn this into a teaching moment. An internal combustion engine must be rotated at a great enough speed to suck both fuel and air into the combustion chamber(s), while the intake valve(s) are open, and continue turning as the valve(s) close to compress the mixture which will be ignited by a timed spark. The starter motor is a compact device that packs a lot of punch and is geared very low to turn an engine over (via the flywheel or flexplate) to provide said rotation. The challenge is engaging the starter motor only when necessary. Bendix versus pre-engagement (using a solenoid) – two very different animals.

Vincent Hugo Bendix (really interesting guy – look him up on the web) developed the Bendix drive in 1910. As per Wikipedia,
“The Bendix drive places the starter drive pinion on a helical drive spring. When the starter motor begins turning, the inertia of the drive pinion assembly causes it to wind the spring forcing the length of the spring to change, and allowing the pinion to engage with the ring gear. When the engine starts, backdrive from the ring gear causes the drive pinion to exceed the rotative speed of the starter, at which point the drive pinion is forced back and out of mesh with the ring gear.
The main drawback to the Bendix drive is that it relies on a certain amount of ‘clash’ between the teeth of the pinion and the ring gears before they slip into place and mate completely; the teeth of the pinion are already spinning when they come into contact with the static ring gear, and unless they happen to align perfectly at the moment they engage, the pinion teeth will strike the teeth of the ring gear side-to-side rather than face-to-face, and continue to rotate until both align. This increases wear on both sets of teeth. For this reason the Bendix drive has been largely superseded in starter motor design by the pre-engagement system using a solenoid.”

The pre-engagement system uses a solenoid (using an electromagnetic engagement) to move an actuating arm, forcing the pinion (drive gear) onto the flywheel, typically when the ignition key is in the “start” position. When the key is released, the power is dropped from the electromagnetic circuit and the solenoid returns to its original position. As such, when functioning properly, the starter motor is only engaged during the starting operation.

In your case, it appears that the solenoid is not functioning correctly and therefore failing to move the actuating arm and engage the pinion gear with the flywheel. Pretty straight forward fix and in most cases, a rebuilt GM starter motor comes with a new solenoid.

Count me out,Cowboys.

Originally Posted by Stroker51

And I damn well know my information is not bad.this sounds like one of them know it all bull shit sites. How stupid can you get about something simple as a starter

Well, sometimes even a simple starter motor has a lot of technical info behind it. And the words we choose to call things do make a difference. I hope you'll reconsider you final post above. We aren't a bad group of guys. And we like sharing our knowledge.

Originally Posted by Gangi

Now when I go to start it it doesn’t crank it just makes the noise of an electric motor humming. The battery is charged but when I crawled underneath I found that the noise was definitely not coming from the starter. Btw I’m a little new to auto mechanics and this car is like a first project

JMHO, and, in my own experience, when there is only a hum from the starter (usually no click and the starter motor does not spin), it is a stuck / frozen solenoid plunger.

When this happens the solenoid coil activates (hum noise) but the plunger does not move, in turn, it does not activate the starter motor (motor does not spin) because solenoid switch contacts do not close or engage it, and the starter drive mechanism does not push out into the fly wheel (no click).

GM solenoids are usually located on top of the starter motor, which can make the noise (hum) location a little difficult for some to determine as it is coming from on top and not actually from the starter motor itself. A stethoscope or wooden dowel can greatly aid in noise location diagnostics.

An old (temporary) fix for a stuck solenoid, was to tap the solenoid (top of starter) with a rubber mallet or wooden handle.

Way back when you could rebuild, more or less, a GM solenoid. You could take apart the disc assembly and reverse the disc exposing the unburnt side. Emery cloth to the 4 contacts, battery, starter, r and s, and you were good to go. The "R" terminal was discontinued with the advent of HEI distributors.

Originally Posted by NTFDAY

Way back when you could rebuild, more or less, a GM solenoid. You could take apart the disc assembly and reverse the disc exposing the unburnt side. Emery cloth to the 4 contacts, battery, starter, r and s, and you were good to go. The "R" terminal was discontinued with the advent of HEI distributors.

I remember those days!! Many a road side repairs like that in my youth!!!