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6.5 Starter issues

All American

All American

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Messages
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Location
Temecula, CA
This has happened on my 6.5 non turbo and my 6.5 turbo trucks... The starter seems to want to push away from the flex plate when cranking, and ends up sliding over just enough to not mesh properly, and causing a laundry list of problems; chewed up starter teeth, flex plate teeth, pulling out the starter bolt threads, the non turbo even cracked the back of the block just behind the bolt holes for the starter! :WTF: I have the little bracket on the front of the starter to the block on there. Any suggestions? I have 2 dead trucks for the same issue! I have to believe this is somewhat common and someone here has dealt with it! Thanks :mad2:
 
I am using the standard style starter bolts, it called for M10x1.50x113mm. The last guy had the wrong starter (old model?) and one bolt was a 1.25 pitch. I ran a tap in both holes and put in brand new bolts. I am running the front bracket that goes from the starter to the block. Today I tried starting it and the bellhousing of the starter cracked completely off.
 
Sorry I'll clarify. The non turbo truck broke the back part of the block. Today I tried the turbo truck and I pryd the starter over as I tightened it, it made about 1 full rotation then pushed away enough to skip the teeth, when I crawled underneath, the bellhousing of the starter was cracked all the way through, I guess twisting force of the bendix?
 
Man, I have no idea how that happened. Are these starters original equipment, or aftermarket? Are they the right ones?

I've never seen a starter that was properly tightened and secured do that. Wish I could offer a suggestion.
 
Yeah it doesn't make sense at all. I'm hoping someone on here has experienced this. It's a rebuilt starter from the autopart store I use, 3rd one actually, I'm pretty convinced it's not the fault of the starter. What about the torque converter cover? It's heavy cast aluminum and seems like it may help hold the back of the starter from sliding, and when the last owner had the wrong starter on it, it broke that cover. Is that thing necessary?
 
Remove the "rock guard" that covers the torque converter with the 6 bolts. That is all it is for. Remove = take it out of your mind as ANY use for holding the starter. In fact it is sometimes in the way changing the starter out.

You need to inspect the flex plate for severe damage as it could be cracked, broken, or damaged/worn gear. Hitting the starter from above is the damage you are looking for beyond being cracked or broken.

Starter is held in place by two bolts AND a bracket in the rear of the starter to the block. Missing this bracket will allow the starter to bust the block. That kind of stress can also bust the starter too. If you are missing this PIA to install bracket... It 'missing' is a known problem and block killer.

There should not be much wiggle room on the 2 main starter bolts. Are the bolts knurled just above the threads? Get new bolts from your GM dealer and compare to what you are using. The ones in your OP are suspect for cracks, stretching, etc. just from the starter being busted up on them...

I have never pried a started one way or the other when installing it. I don't recommend it or see the need.

Rebuild shop using 6.2/6.5 starter parts? They are special for this engine with direct drive and gear reduction drive units used.

Here is more info on mounting the starter.
http://www.thetruckstop.us/forum/sh...acing-etc-Questions&highlight=starter+bracket

Close up pic of the must have bracket, P/N's in above thread.

http://www.thetruckstop.us/forum/sh...n-t-know-I-had&p=263991&viewfull=1#post263991
 
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Good to know about the cover. I do have the front bracket on the starter to the block. It was not there previously when the block broke on the previous owner for the non turbo truck. The turbo one I've been working with does have it, I put 2 brand new starter bolts and chased the threads in the block, and I just installed a brand new flex plate when I did the starter. It's ALL new. The holes in the starter that the bolts run through are as you know slightly larger than the bolts, this allows minor play, so that is why I put pressure on it when tightening to get all the help I could to get it close the the flex plate. When I replaced the flex plate and starter and bolts, it starter fine for about 6 times. Then it went to shit again.
 
What year are we working on?
Are you using ether? (A big no-no) Something may be kicking the engine back against the starter?
 
Not positive on the year. Someone previously dropped a 6.5 turbo in an 83 suburban 4x4. No ECM. I guess 94-96 ish? And no it's straight diesel. And when I first put the new parts it started great, and I manually engaged the bendix to look at the clearance between the teeth and it looked great, now it's too far, it somehow slid. Does anyone make a performance starter maybe?
 
I aint 100% sure but a 83 bellhousing might be different from a let say 92 0r 93,maybe that starter is not lined up properly cause of bell housing interference at the starter nose. the starters for the older models have a shorter nose cone.

I know i had that problem when i installed a 6.5 starter on a 86 6.2 with standard tranny bellhousing,i had to grind the bell housing out to get the starter nose to fit properly.
 
I know it's engaging, when it's acting up i have gotten under there while someone else turns it over, you can see it barely catch the flex plate and push away enough to skip the teeth. And the suburban is an 83, but the engine and the starter are the correct match. He had the improper on in before, I cleared this up when I purchased the truck. I'm worried the holes in the block are oblonged from him having the wrong starter and not having that starter to block bracket on there, now giving it just enough play to give me a headache
 
Can you post a couple pics.

Are these bolts still stock size?
I can't see the mount holes getting oblong to the point that the drive won't engage the ring gear,the bolts will break before that happens.
What i can see is a mis matched starter drive/ring gear.Wrong starters perhaps?

A couple things a guy can try to get a solid starter/block line up if slop is the issue..
1,install short hollow dowels in the mating face of the starter and drill the block to match.
2, drill the starter holes up 1 size(in standard)and tap the block for same.You got the untreaded part of the block as guide for the tap.
 
I can get pics today, the truck died at my father in laws ranch and Ill be there later today. The bolts are stock size, as I said it calls for M10x1.50x113 bolts, the genius before me had one of them with a 1.25 pitch, so I bought brand new bolts so the serration would be good as well, and I ran a M10x1.50 tap through the block on both holes. Now as for the proper starter. The guy I bought it from said he had starting problems ever since he replaced the starter the second time, the last one had lasted him about a year (which seems very premature as well) I noticed the teeth were gone on the flex plate and starter, so I ordered new of both. The parts house that I use is very knowledgeable, not your average Autozone boneheads, and they said there is an early model and a late model. I brought both to the house and he had the "early" model in there, so I mounted the "late" model with the fixed bolts, and brought the bendix out by hand, it looked great. I started it with no issues. I ran it for a bit and shut it off, started again and great. I did this 4 or 5 times then drove to my father in laws. When I tried to start it that night it was pushed so the teeth were running on top of each other instead of meshing. I guess maybe I can run the block numbers to know exactly what the engine is? Where are they located on this engine?
 
to my knowledge there is only 1 adjustment which requires shims and moves the teeth further apart. sounds like maybe a mismatch of parts. As far as I know the starter diff is direct drive (early) and gear reduction (late). but they should be interchangeable. In order for the teeth to stack on top of each other there has to be a mismatch of parts ie wrong flex plate or starter drive. or the starter it self has a problem that allows the starter drive to move and I'm not referring to the sliding action.
 
The 6.5 and 6.2 flywheel and starter have a different amount of teeth to the gasoline starters/flywheels. When i ordered my flywheel for my manual trans swap i had to specifically order the "diesel" flywheel.

I wonder if you've been given a gasser flywheel/ring gear? That'll cause all sorts of havoc.

My irect drive starter had "no shim" stamped in the casting. I can't remember if the gear reduction 6.5 starter had that stamped in it, but i needed no shims when i installed it.
 
Well I specified diesel but that of course doesn't mean that is what they gave me. It says now shims right on the starter. I guess I have to run the engine numbers to see exactly what I have to ensure proper parts. Where are the numbers located that I need to use?
 
All 6.2 and 6.5's blocks are the same as far as starter mount and dimensions go regardless of year.
There is no reason for a starter not to line up and stay lined up.
AS far as i'm concerned the newer starters don't require shims(says so on the starter).
I would look for a tight fit of the bolts trough the starter housing where they come out,stock bolts have a knurled section just above the treads that act as dowels.
A smooth shanked normal machine bolt might have to much play there,allowing the starter to shift away under the gear action from the ring gear,bending of the bolts in the dowel section of the block will give more side play yet and facilitates bolt breaking.
 
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