96 LT1
A few years ago I had a bad spark plug causing kickback and the starter finally started making noise. I also had something rattling around in the TC cover which I assumed was a TC bolt. I got under it expecting to find a snapped starter bolt (or worse, a broken boss) but to my surprise, the nose of the starter had broken off and was rattling around in the TC cover.
Bought new starter, fixed the misfire, and the starter lasted about 5000 miles (which unfortunately was about 2 years later so no warranty). This time, the starter not only broke the nose off (which I fixed by just removing the TC cover permanently) but it also snapped the shaft right behind the starter gear. New starter again, and it lasted maybe a dozen times before snapping the nose off again.
What gives? Why on earth is it snapping the nose off? I triple checked that none of the flexplate teeth are damaged or missing.
In reply to Curtis :
My 1997 350 went over 371.000 miles on the original starter. It’s not the design. Check the alignment and that the flex plate isn’t bent.
I'd bet it's mounting a bit too close to the flex plate and stressing it.
Brand new Chinese casting?
For some reason, you are shocking the starter. You don't have the drive kicking out and back in for some reason? Starter relay not holding correctly?
Any time I have seen that, it was due to too much initial timing causing the engine to kick back against the starter.
That... should not be an issue on an LT1. And if it were, you'd KNOW it by the way the engine would (not want to) crank.
Streetwiseguy said:
Brand new Chinese casting?
For some reason, you are shocking the starter. You don't have the drive kicking out and back in for some reason? Starter relay not holding correctly?
Since the relay is part of the starter, it gets replaced when I replace the starter. I guess it's possible that I've had three bad relays in a row, but unlikely.
And the probability of chinesium is very high. I don't buy top shelf stuff, but I at least get name brands from the parts store. The one on it now is a reman ACDelco.
Knurled. said:
Any time I have seen that, it was due to too much initial timing causing the engine to kick back against the starter.
That... should not be an issue on an LT1. And if it were, you'd KNOW it by the way the engine would (not want to) crank.
Agreed that it shouldn't be a problem. The Optispark is a new OEM GM part that was put in around 120k along with new wires and plugs. When I started getting the kickback a few years ago, it was determined that one of the wires was no good and had eroded the electrode/collapsed the gap. It was definitely kicking back then, but new plugs/wires fixed it. Now I'm not getting the kickback, but the starters keep busting.
Maybe lends credence to frenchyd's suggestion of bent flexplate.
Has there ever been any shims between the starter and the block? And check the clearance between the starter pinion and the flywheel.
Never any shims, but it's worth checking clearances. I have yet to have an SBC after about 1975 need shims unless you have an aftermarket flexplate or starter. The way they cast the blocks it is nearly impossible to get radial core shift. The fact that the factory starter lasted 120k and I only had trouble after the misfire/kickback suggests that it isn't a shim issue, but you're right... worth a check.
My ear is also pretty keen on how an incorrectly- aligned starter sounds, but that isn't very scientific.
In reply to Curtis :
Any chance you still have the factory starter to measure? Maybe try to measure an oem at the JY?
zordak
Reader
10/14/19 9:12 a.m.
My experience with braking the nose on a SBC starter was the to much clearance between the starter and the flex plate. They used to fix this by shimming the out side of the starter. But since the first starter lasted so long I am inclined to go along with flex plate damage the first time around.
In reply to Curtis :
I have personally witnesed a starter kickback make a flexplate eggshaped. You'll definitely hear it if you disable spark/fuel and keep cranking it around.
Oooooh... that sounds like an easy thing to try. Thanks.
Vigo
MegaDork
10/14/19 3:05 p.m.
I would honestly just stick shims under it until you reached an obvious tipping point where you were making it worse instead of better. If you leave the big wire off the starter you can pop the gear out without spinning it (by cranking at key or jumping power to solenoid wire) and see what it looks like. Just don't leave it engaged for a long time or it might (im not sure, but maybe) overheat the solenoid windings and short itself out.
grover said:
In reply to Curtis :
Any chance you still have the factory starter to measure? Maybe try to measure an oem at the JY?
No. Long gone. Turned in for a core. I called a GM parts counter today to see if they had one I could measure, but they'd have to order it.
Any chance that on the original starter the starter brace was left out during reinstallation? I know some SBC's had them, but I'm not to sure on the LT1. Cheap enough to put one on. Looks like this...
No bracket on it now, and I don't recall ever having one.
Looking over parts diagrams I don't see one.
There was never said bracket on my 95 9C1.
