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Starter problem

k51977blazer

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Feb 11, 2007
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Cocoa Florida
I have a 1976 blazer with a 350 my problem is my starter seems to move after I start it maybe 10 times, I go underneath unloosen the bolts move it then works again I have tried 3 different starters and I have the correct bolts, I have tried with and without shims any help would greatly be appreciated
 
Thanks everyone I’m going to order one from summit racing, I’m using the right bolts the knurled ones, I never had this problem before thanks again
 
I've never seen this problem with a 350, the 6.2L diesel commonly had a similar problem when the factory starter brace isn't installed. GM did not put a starter brace on the gas motors normally. Did you get new bolts or reuse old ones?
 
We may need to figure out where the starter nose cones are coming from. As mentioned I can't see how they should have enough slop in the bolt holes to allow the starter to move a meaningful distance. At least not before some sort of wear has already occurred.

I can see cheap aftermarket nose cones being made improperly or cores being reused that shouldn't be.
 
I tried two sets of bolts and 3 starters all did the same thing I ordered the brace so we will see if that fixes it if it doesn’t im lost
 
There is bracket that you can get to connect it to the block so help keep in place. Check the knurled bolts make sure they are in fact knurled.

If you go with a mininstarter you won’t need that bracket, as they don’t weight anywhere close to what stock Chevy starters weigh.
 
I had that problem on a mini starter. The factory bolts bolt would be tight, the the starter would move. It was the fact that the bolts were bottoming out holding the starter tight, till it started spinning.
 
I had this problem once on an old Datsun 240 that I dropped a 383 into. One of the mounting holes on the block had a hairline crack that would stretch when the engine got hot, loosening the starter. Had to buy a different kind of starter (mini, high-torque starter from summit racing) that used the linear mounting holes, instead of the diagonal ones used by the factory starter. (small blocks have three starter mounting holes). I supposed I could have tried a Helicoil to fix the issue, but hindsight is 20/20, right?
 
I have one on my truck I put it there. most of them don't survive the fist starter change. The rebuilt starters don't have the studded, bolt or it in the wrong hole. The bracket also make the positive cable a more difficult to install/remove.
 
I had similar problems on an old 350, found the block cracked on the outside bolt, went to a starter rebuilder and found a starter that used all 3 bolts and I put the brace on. I also had to grind down the mounting surface to get the proper distance of intersect between the flex plate and starter gear. I use a paperclip but I know there is a figure for how much it should be. put the paperclip in on top of the starter gear, I would hold it out with a screwdriver. Once I did this no more issue.
 
Easy way to adjust the starter drive clearance..
Use a 1/8" drill bit or allen wrench between the starter armature shaft and the outside of the flywheel teeth..the clearance is correct when the drill bit or allen wrench just fits snug in between the two--if not,add or remove shims until it does..

I found this method on the instructions that came with a rebuilt starter years ago,tried it,and it worked perfect on the first shot...so I've been using it ever since..
Other methods require using a small screwdriver to push the starter gear out (there is a hole in the starter nose for that purpose--take off the positive cable first or the starter will start cranking when you force the starter drive into mesh with the flywheel !)--then they say to use a wire feeler gauge between the flywheel teeth and the starter drive gear at the bottom of the tooth...this only takes 4 hands,and is dam near impossible to perform lying under the truck!..

Or you can just add or remove shims repeatedly until it "sounds right"..in my experience the less times you loosen & tighten starter bolts the better off you are...the block's threads can get boogered up easily or get "loose" and cause more grief..also make sure there is no crud jammed into the bottom of the block's bolt hole threads...that can make the bolts bottom out before tightening against the starter--or worse,push the crud into the casting as you tighten the bolt,and possibly crack it..
 

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