Problem breaking starters

[72longhornTX]

I am having an issue with starters breaking to nose cone off. I have a 1982 Chevy K-30 with a 454 and 700r4 in it. I have been through 3 starters and watched the gear as it tried to start on one of them and it looks like the gears were skipping so I tried shimming it all different ways and nothing was working. Then the nose cone broke in half.

I have been told it could be a cracker flexplate but don't want to drop the trans just to find out. Any ideas on what it could be?

The truck ran fine up until all this happened.

[ray_mcavoy]

Instead of just randomly trying different shim combinations, it's best to actually measure the clearance between the gears. With the inspection cover and solenoid temporarily removed, pull the plunger out to engage the starter pinion gear with the ring gear. Clearance (from the tip of a pinion gear tooth and the root of the ring gear) should be in the .035" to .065" range. A paperclip (about .045" dia) makes a good feeler gauge.

If you need to increase the clearance, add a long shim that goes across both bolt locations. If the clearance needs to be decreased, use a short shim only at the outboard bolt location.

Some other things to check:

(1) Make sure you're using the correct style starter bolts with a knurled shank.
(2) Make sure you're using a starter-to-block brace to support the forward end of the starter motor.
(3) Check the timing to make sure it's not advanced too far, causing the engine to kick back against the starter.

[72longhornTX]

Once I read about how to measure the gap was after the last starter broke. I will do that with the new starter this next time.

Now with that brace. I have heard people say that but I have never been able to see a picture of this mystery brace or where to get one. The auto parts stores have nothing about them.

How do I check timing when I can't even get the starter to turn the engine over?

[hopped up]

Your flywheel bolts could be loose , gotta drop the tranny to check. 3of mine were finger tight and 1 was missing! That was one problem still having other problems with my starters
Posted via Mobile Device

[ray_mcavoy]

Here's a pic of the type of starter brace I'm talking about:



This particular example is on a small block, but similar braces were used on big blocks as well. Finding one can be a bit tricky since they were commonly thrown away when someone replaced a starter and didn't figure it was necessary. You might still be able to get one from a GM dealer or restoration parts supplier. Or look for one at a junkyard. You could probably even make a homemade one from a small piece of angle iron.

I can see where checking the timing could be a bit difficult in your situation. And unless something was recently changed that would have disturbed the timing, you'll probably be okay with getting the new starter shimmed/braced properly. Although, I suppose you could set the static timing like you'd do after replacing a distributor and then fine tune it with the timing light once it's running.

[72longhornTX]

Thanks for the advice. I will look into finding a brace like that or making one. Will do some shimming tomorrow and see what happens. Maybe I can figure something out.

It's the damnedest thing though. It ran fine for 6 months of me owning it plus before then one day the starter blew up the nose cone and it's done it 3 more times since. Hoping it isn't the flex plate.

[ray_mcavoy]

Yeah, the fact that it's all of a sudden started having this problem does kind of suggest there might be a problem with the flexplate.

It might be a good idea to turn the engine by hand using the balancer retainer bolt (remove the spark plugs if necessary to make it turn over easier) so you can check the starter pinion gear to ring gear clearance in 3 or 4 different positions around the flexplate. Basically checking to see if you have some sort of runout condition that's making the clearance tighter/looser in certain spots.

[72longhornTX]

Alright. I can do all that tomorrow. Thanks for the advice. I have read quite a bit just now about them all and some people have said the bolt holes in the starter could be too big and have slop. I guess I will need to take the bolts up to the store and try the different starters as well.

[motornut]

maybe the flexplate is worn out
on my SB 350 it looked ok, till it was out and compared to a new one