1985 K5 keeps breaking starters, help!

[DnS421]

Another thing on my Burb that was eating starters until I got the flexplate replaced: the distributor cap was really bad corroded, and the rotor wasn't great either. I think the PO probably ran it too long like that, and it misfired bad enough to not be firing properly right as it started? Hopefully that kinda makes sense....you know how the #5 and #7 like to try to fire at the wrong times if the spark is bleeding through the cap or jumping across the wires.
That's something else to look at....

All new plugs, wires and distributor and cap and rotor. I’m going to put a timing light on it and make sure timing is set properly on Monday.

 

[DnS421]

Are you still using the factory big size for the age starter?
Or have you stepped up to the mini starter from the mid 90's?

We run the mini starters on everything now.
From a 250 straight six, small blocks, and our big block.

I’m still using factory big starter.

 

[DnS421]

There's another issue going on for sure. Does the engine start perfectly smooth or does it start a bit unsteady and kick back a bit?

Starter shimming shouldn't be done willy nilly style. You shim for proper clearance. You can check for proper clearance with an 1/8" drill bit as a feeler gauge, then shim accordingly.

One other tidbit, by the 80's the Chevy V8 starters were smaller and lighter than what was used in the 60's and 70's and many models did not have a brace. Which is why they are almost always "missing".

Engine starts perfectly smooth. I know it has to be hitting or it wouldn’t break I just can’t pin point when it hits. I have already checked the clearance with a drill bit and it was perfect and had the brace and proper bolts so I know it didn’t move and still broke the starter. I have a flex plate in the truck brand new in box still I just haven’t had time to install yet. I was wondering if mine might have a warped spot in it. The teeth on it look good though.

 

[DnS421]

Not saying this is your problem,but it was a problem for me once,it was a real head scratcher. Look at these 2 nose cones one has a recessed area right around the bolt holes,one doesn't. I had a block that was thin enough at one edge,you'd put a starter on it would work fine short term,then walk off the edge of the block drop that recess over the corner then, I'd break another nose cone.Went through a dozen starter boxes until I found one without the recesses,problem solved. It's worth looking at.

Never seen this suggestion anywhere else. I will pull my starter back down and check that.

 

[bucket]

Engine starts perfectly smooth. I know it has to be hitting or it wouldn’t break I just can’t pin point when it hits. I have already checked the clearance with a drill bit and it was perfect and had the brace and proper bolts so I know it didn’t move and still broke the starter. I have a flex plate in the truck brand new in box still I just haven’t had time to install yet. I was wondering if mine might have a warped spot in it. The teeth on it look good though.

When you are pulling your starter back down, also remove the torque converter bolts and push the converter away from the flex plate. Then you can tug on the flexplate in different directions, looking for abnormal movement or light popping/cracking that would indicate that it's broken around the crank flange.

 

[JBswth]

Not saying this is your problem,but it was a problem for me once,it was a real head scratcher. Look at these 2 nose cones one has a recessed area right around the bolt holes,one doesn't. I had a block that was thin enough at one edge,you'd put a starter on it would work fine short term,then walk off the edge of the block drop that recess over the corner then, I'd break another nose cone.Went through a dozen starter boxes until I found one without the recesses,problem solved. It's worth looking at.

Strange. My 292 is drilled for two different starter noses, one for staggered bolts, the other for inline bolts. I just wore out one with the inline bolts.

J. B.

 

[Broken85]

Definetly check the timing, sounds like a to advanced problem. Also make sure you are using a timing chain cover with the correct markings on it. If your motor is a Frankenstein, you may be looking at the wrong timing chain cover, or looking at the wrong balancer especially if you used parts from a 305 for a 350 upgrade. Some have timing chain covers have timing marks at 12 o’clock and some have them at the 2 o’clock-ish position. Too advanced will snap the nose cone for sure.

You can get a gauge like this on Amazon for les than $20. Put it in #1 cylinder, crack all the spark plugs and spin the motor by hand to find TDC. That will tell you if the crank, cover and balancer you are looking at belong together.

 

[Ricko1966]

Definetly check the timing, sounds like a to advanced problem. Also make sure you are using a timing chain cover with the correct markings on it. If your motor is a Frankenstein, you may be looking at the wrong timing chain cover, or looking at the wrong balancer especially if you used parts from a 305 for a 350 upgrade. Some have timing chain covers have timing marks at 12 o’clock and some have them at the 2 o’clock-ish position. Too advanced will snap the nose cone for sure.

You can get a gauge like this on Amazon for les than $20. Put it in #1 cylinder, crack all the spark plugs and spin the motor by hand to find TDC. That will tell you if the crank, cover and balancer you are looking at belong together.

An easier way of doing this,without waiting on a special tool and just time involved. Put a vacuum gauge on manifold vacuum, loosen the distributor clamp, advance the distributor until you have the most vacuum,now retard it until vacuum just starts to drop 1or2 inches. Now disconnect and plug the vacuum advance and check timing with your light if marks are close then your cover and balancer are fine. If they aren't close run it with the timing set by vacuum until you get a piston stop. Then you can remark or replace the balancer,depending. If it's the wrong year balancer,just remark it. If it's slipped replace it. And just to clarify when you use a piston stop you go clock wise by hand until you hit the piston stop then make a mark on the balancer to line up with zero on the timin cover. Now go counter clockwise by hand until you hit the stop make another mark on the balancer. Halfway between the two marks is TDC.