1985 K5 keeps breaking starters, help!

[DnS421]

I have a 1985 K5 blazer, 350 engine th350 trans. My problem is that I keep breaking starters. I went to the Chevy dealership and ordered factory GM knurled starter bolts, I have tried everything form no shims at all up to 5-6 shims and everything in between, half shims on one side or the other, I have added an extra ground to the starter and I have the starter bracket that’s almost always missing and still the starter is breaking. The starter doesn’t grind or sound like it’s hitting at all but obviously it is because when it fails it either has busted teeth or a broken nose cone. What could possibly be the issue?

 

[squaredeal91]

I have a 1985 K5 blazer, 350 engine th350 trans. My problem is that I keep breaking starters. I went to the Chevy dealership and ordered factory GM knurled starter bolts, I have tried everything form no shims at all up to 5-6 shims and everything in between, half shims on one side or the other, I have added an extra ground to the starter and I have the starter bracket that’s almost always missing and still the starter is breaking. The starter doesn’t grind or sound like it’s hitting at all but obviously it is because when it fails it either has busted teeth or a broken nose cone. What could possibly be the issue?

My first thought is that the timing is too advanced. Check base timing with a timing light.

 

[PrairieDrifter]

You need to make sure you match the starter to the ring gear. Theres two different tooth counts for the ring gears.

 

[squaredeal91]

You need to make sure you match the starter to the ring gear. Theres two different tooth counts for the ring gears.

I forgot that lol. 168 and 172? Can't remember fir sure

 

[HotWheelsBurban]

I forgot that lol. 168 and 172? Can't remember fir sure

I think it's 168 and 153? Also be sure the flexplate is tight on the crank and torque converter, and all bolts are tight. One of the problems our '81 Sierra had was probably a loose bolt on the flexplate. But it didn't act up very often, and you could get it to start by bumping the key a couple times to move it over the rough spot. Current OBS Burb had bad teeth on the flexplate, and you could get it to cooperate by bumping the key. I replaced the starter a couple of times, and then after the bad teeth on the flexplate got bad enough, it blew the drive end housing off the starter! After that it went into the shop to get the flexplate replaced.

 

[Rickf]

I had a 6.2NA that ate starter bolts until I found out the starter to block brace was missing.

 

[85K304SPD]

I have one 350 that takes a washer, between the starter and the block, on the outside bolt and nothing on the inside bolt. No combo of shims would work right. I had to take it on and off many times to figure it out. It works great now. Don't give up, try different stuff.

 

[DnS421]

I have one 350 that takes a washer, between the starter and the block, on the outside bolt and nothing on the inside bolt. No combo of shims would work right. I had to take it on and off many times to figure it out. It works great now. Don't give up, try different stuff.

Thanks for the advice, I currently have it running on two extremely thin shims, waiting for the inevitable failure and will probably upgrade to an ac delco starter to see if it last longer.

 

[DnS421]

I had a 6.2NA that ate starter bolts until I found out the starter to block brace was missing.

I already ordered and installed the block to starter brace and have replaced atleast four starters since installing the brace

 

[Ricko1966]

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.

 

[Blackbeard44]

maybe try to find a steel nose cone starter

 

[HotWheelsBurban]

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....

 

[bucket]

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".

 

[Catbox]

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.

 

[Shorty81]

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 also use the high torque mini starter on my big block, so far so good.