ten tooth bendix versus 9 tooth

Hi Folks, I have an interesting problem.
I have a 1984 Chevy Blazer 4x4 with a thm700r4. The original engine was a 305 and it was replaced, by the original owner, with a Mr.
Goodwrench 350.
After the swap, the engine acquired an appetite for starters. Every three months or so, the starter fails. (Of course, the owner did not tell me this when he sold the blazer.)
I have been going nuts, trying to solve the problem. I even bought a GM rebuilt starter and ring gear and made doubly sure that the starter was shimmed correctly.
Currently, the truck is located in a small texas town on the border with Mexico and I asked a local mechanic to look at the problem. He said something that was very interesting. He has seen that problem four times - that is, GM Goodwrench Crate Engines that eat starters. The solution is to replace the 9 tooth bendix with a ten tooth bendix. The ten tooth bendix is not available in the US, you have to go to mexico to get it.
Has anyone run into this problem and solution?
-David
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What do you mean exactly by "the starter fails" ?
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[ followup at the bottom ]

Scott,
Both the ring gear and the bendix pinion get chewed up. I have replaced the starter four times and the ring gear twice. The last time I replaced the starter and the ring gear, I used GM parts.
Note that the block is drilled for two kinds of starters: one with two bolts in a diagonal pattern and the other for two bolts at the front of the starter. All four starters used the diagonal pattern - the GM parts man swears that the diagonal pattern is the correct one.
I wonder if somehow I got a block that was intended for a different market - say Mexico.
Also, in what applications is the front bolt pattern used?
-David
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wrote:

I may have this backwards, but the diagnal pattern is for the 168 tooth flywheel and the straight pattern is for the 153 tooth flywheel.
-Bret
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wrote:

Bret,
How many teeth are in the bendix for the 153 tooth flywheel and when is the 153 tooth flyweel used instead of the 168 tooth flywheel?
-David
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engine
Every
not
a
starter
He
starters.
bendix.
If I remember correctly the 168 tooth flywheel is 14" in diameter and uses a starter with holes at an angle. The 153 tooth flywheel is 12-3/4" diameter and uses the straight across bolt holes.
It's been a lot of years since I've built small blocks but I don't think that wrong starter will fit the wrong flywheel. I can't swear to that it's been a looong time. But when you have the starter bolted on with out the solenoid, push the drive gear into the flywheel and you should have about 0.030" clearance between the flywheel teeth and the drive gear.
Brian
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wrote:

I got the wrong starter from NAPA once and the bendix freewheeled without meshing at all. -- Best Regards Gordie
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wrote:

don't know.... never had a GM product w/ the 153 tooth flywheel.
-Bret
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">>

So when you installed it and talked about shimming it----was it nice and quiet when cranking? It sounds good but still eats the ring gear?
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Yeah, it is nice and quiet. But after a month or so, it seems to labor when cranking the engine but not all the time then on the third month, the bendix finally fails. It is almost as if there is a sticky spot in the engine and if the engine stops on that position, the starter motor has problems cranking it - the closer it gets to the failure point, the more the binding. Just before then final failure, the sticky spot can only be overcome with additional power using jumper cables.
We have checked the charging system at that point and the battry and charging system are fine. I put new starter cables and made sure that all grounds are in good shape but the problem still persists.
-David
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wrote:

First off looks like you need to do some serious research to get the correct starter. Check out this site, it shows "upgrade" starters and talks about upgrading 9 tooth to 11 tooth and such..... http://4alterstartcom.verizonsupersite.com/highperformance /
Also, as someone else said check for 30 thou clearance. I dont know if that number is correct but sounds resonable. (research that too) I would also have someone crank the thing and watch very carefully the flexplate/ring gear and starter to see if angthing looks funky as its spinning. Anything out of round or whatever, anything. Do you have *any* other problems with it like overheating a bit or steam or smoke in the AM out the tailpipe. Does/did it crank smooth (before the failure) both hot and cold? Or did it have that little drag at first even when it seemed to crank ok? Have you ever checked how much the starter pulls (amps) over about a five second or so crank. It would be interesting to watch the amp meter too see if it is steady or jumps up at a certain point in the cranking. Get the numbers off the block and see if someone can tell you what motor it is for sure........
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wrote:

Are ALL grounds there? Is the frame grounded along with the body and radiator support and firewall in addition to the engine? I had one where it would crank fine but after a few months, it would eat starters. Turned out the ground to the body was bad.
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First off looks like you need to do some serious research to get the correct starter. Check out this site, it shows "upgrade" starters and talks about upgrading 9 tooth to 11 tooth and such..... http://4alterstartcom.verizonsupersite.com/highperformance /
Also, as someone else said check for 30 thou clearance. I dont know if that number is correct but sounds resonable. (research that too) I would also have someone crank the thing and watch very carefully the flexplate/ring gear and starter to see if angthing looks funky as its spinning. Anything out of round or whatever, anything. Do you have *any* other problems with it like overheating a bit or steam or smoke in the AM out the tailpipe. Does/did it crank smooth (before the failure) both hot and cold? Or did it have that little drag at first even when it seemed to crank ok? Have you ever checked how much the starter pulls (amps) over about a five second or so crank. It would be interesting to watch the amp meter too see if it is steady or jumps up at a certain point in the cranking. Get the numbers off the block and see if someone can tell you what motor it is for sure........
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the 305 to 350 swap I did in a 1984 Monte Carlo required me to change starter applications. I used the 350 flywheel with a 350 starter with no problems. I know the bolt pattern that you are speaking of is one for a 305 vice the other for a 350 starter. If memory serves, the diagonal pattern is for the 305, and the parallel is for the 350.

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