Cracked Bolthole on Block for Starter

[zdubz]

First off, I'm a novice and am struggling to shim my starter. But I want to give a quick summary to explain the pictures and why 1 bolt is longer and using washers at the head.

A faulty fuel gauge resulted in running out of fuel. After refilling I found my starter to be grinding. I had only had the truck for a month and I did not know about the starter bracket at the time, but the previous owner didn't have it connected and I found the outer bolthole was cracked along the edges so taking some advice I drilled a little bit farther up into the block and re-tapped threads in the hole. I couldn't get the old starter or a refurb one to meet the flexplate right even with several shims so I replaced the flexplate by advice of a GM mechanic.

Now even with new flexplate I have the same problem I did before, which is the bendixon gear grinds and will not disengage even when shimmed alot. So far the only way I have been shimming when I say shimming is placing a shim around both bolts simultaneously. I don't know if I can shim just 1 of the holes or use washers instead or what, but in reading online it seems that some people do that.

Maybe I didn't HAVE to replace the plate just yet, I'm grateful I learned more about my truck but still can't even get the basics of shimming a starter down. Does anyone have experience on shimming just 1 bolthole or using flatwashers or which direction shimming 1 of the boltholes would move the bendixon gear?

I'm thinking it needs to have 1 shimmed more than the other but I can't tell which or if that's even a real thing just from reading forums online. Here are some photos of the cracking bolthole, longer bolt, and where the gear is failing to disengage. I just don't want to shim excessively and chip ring gear teeth on the new fly. Thanks in advance.

 

[doghead]

https://www.youtube.com/watch?v=r5a8kVUKht4

 

[doghead]

https://www.youtube.com/watch?v=DT5_b4BQWDk

 

[doghead]

And also, there's the technical manuals.

 

[zdubz]

Thanks,

I had actually already watched those videos as well as ones from eric the car guy, chris fix, and other youtube stuff before coming to ya'll on steel soldiers.

The technical manual says not to shim over 4mm or 1/8th inch basically. I put every combination of these shims in from 0mm to 4mm, or from 1/62 to 1/8th and no matter what the spacing the bendixon gear still sticks to the ring gear. It wont engage properly, grinds, and will not dis-engage. Now I am suspecting that this may either be the wrong starter, or may be a result of me having to tap new threads into the block. (Not sure why that would make a difference as long as the starter is snug against the block and the bolt is straight, but hey I know that there is a change to the original system so I want to keep it on the table)

That being said, online sources claim to shim certain bolts more or less than others, even going as far as to cutting shims in half in order to do so.
Ya'll ever heard of that? I haven't found quite enough testimony on line to feel confident in objectivity, but I just don't want to thrash my new plate and gear, or shim over the TM's 1/8th'' standard.

 

[doghead]

You should not need to shim it more than an 1/8".

Maybe try a different starter.

 

[doghead]

What starter do you have?

 

[zdubz]

I think its an AC Delco, on the receipt it says 24v CUCV Delco Starter, then the numbers 10461453, 10465015, 10479611, and 1998409. However the starter itself never had a serial number plate or anything other than a sticker saying 24v. It sure looks like the one that came on the truck and taking it to a parts store they verified it's functionality. It was an Ebay purchase though, and I have never ordered any other vehicle parts from Ebay whatsoever.

 

[cucvrus]

I have seen starter drives that were defective and the Bendix does not engage properly. New or not it should be a No Shim mudder starter nose and I would take it to reputable re-builder and pay to have it checked and looked over. Milling flywheels is no fun and gets to be a PITA if you have to change the flex plate several times. Once and done is a good motto to live by. I would not trust an Ebay new or rebuilt starter. Just my spin. I had this problem early on and it was the gear on the starter. It was rebuilt and had to much grease in the drive. It would get locked part way out and chewed the teeth. I took it in to the re-builder and it worked like a champ. Do as you wish. Many people re-build things and are not qualified to do so. When they have trouble they blame the parts they bought. Mush more to it then adding parts.

 

[zdubz]

I visited GM as well as a rebuild joint today. GM has starters from $300-$700 and the rebuild shop has one for about $175. The shop checked and found both of my starters to be working fine although one was getting pretty hot down where the brushes are but it was running way longer than would be needed to crank so could be as simple as that.

They also ran the part numbers and identified the starters as the correct ones for this truck, and I had checked my receipt and verified again that the flexplate was the right one for my truck. I explained everything from this thread to the techs and they are basically as clueless as I am on why I am having a disengagement issue and not able to get this thing to crank.

One thing I told them was that every time I tried to crank it I was extremely delicate and easy on the key turn and just barely barely flicked it to the start position for a moment. A moment is all I really needed to hear grinding and to tell that things aren't right. I am trying to be as conservative as possible for the sake of the ring gear. After over an hour of discussion these guys just called my truck a problem child and recommended that I go try again because the starter works and they viewed the same photos from above and said it seemed to be lining up well even though its not disengaging. They're reputable around here and I could tell they just didn't really have a recommendation on this.

Like I've said, I tried the starters with no shims, and then everything from 1/64th inch all the way to 1/8th inch of shims on both starters. I can buy a new one, but I'm honestly not confident that that will just solve the issue. Fortunately the shop said they'll refund I get from them doesn't work. Just wanted to reach out here before anything and see if there's any more advice from any parties to be had before spending $$$.

 

[firefox]

You did get the correct support bracket for this starter and you are using it, right?

 

[cucvrus]

And did you have the batteries load tested? If the starter is going out and gets low amperage it will not properly engage the flex plate. The crack in the mounting boss indicates a twist to the starter bolts. Like Firefox said the support bracket is key to that starter doing the job correctly. Do you have a no shim nose. And what does a 1/64" shim look like. Never seen one. it seems it would make little difference in the engagement. Check the batteries and make sure the support bracket is in place. unless you have teeth knocked off the replacement flex plate already. Good Luck. Report back.

 

[richingalveston]

I am having the same problem with my truck. I have found that my flex plate is bad. it is brand new from rock auto and the correct one but it grinds and starter does not disengage

checking the flex plate closely I found mine to be warped, you can set it walking back and forth as it goes around.

I have not had the time to remove it but I plan to put my old one back on that was working with the existing starters that I have.

lay under the truck with someone cranking it and see if yours wobbles also. maybe we both got new ones from a bad batch

 

[cucvrus]

Did you ever have one that was tight on the dowel pin of the crank? I have had that before and they seem to get a curve to them when you are tightening them. I used a stop bit on one and just enlarged the hole enough that it slipped over the dowel pin a bit easier. That dowel pin can act as a push nut and if it is not exact it can require more pressure from the bolts on the crank then acceptable to tighten IMHO. Also I use new bolts to the torque converter every time. Not sure how the flex-plate could warp if it is bolted tight and torqued. Could be possible. I have had broken, bent and cracked ones and warped on stick shift trucks and cars. I had one bent because a genius ran his with no both cover and backed into something and bent the flex-plate tight against the oil pan of the engine. Flex-plate is a $50. item at most parts stores. GM used to offer a correction flex-plate to stop milling. I bought a few. When the supply dried up I opted for take offs and new ones from Autozone or NAPA. Good Luck.

 

[Sharecropper]

Why not simply obtain a NOS flex plate on our favorite auction site? The GM part number is 14077158.

That is what I did. If my aching back will ever let me I am going to install my "new" 700R4 transmission in my M1028. While accumulating parts I bought a NOS plate and it is still sitting here behind my desk with the original GM sticker on it.

 

[cucvrus]

Is there some difference in a GM and a NAPA flex-plate? It is a round balanced piece of steel with teeth and if it fits it works. I worked at a GM garage. When we didn't have the right parts in stock we put on the parts available. I used to like Genuine GM Parts for a Ford Chrysler. They are mostly made at the same place just stickered different. They all break and fail eventually. I have Genuine GM Made in China (Mainland) My point is they are equal replacement parts. Used is even good if you can find one that is not milled.

 

[dependable]

On a side note, I would suggest you do not re use the bolts pictured in 3rd picture on original post. One is not even a starter bolt, no knurled shoulder. GM part or AC part number 15544950 is what you want. I usually use new bolts whenever I have to replace starter, as they can get bent, and have often been over torqued.

 

[Mg84648]

On a side note, I would suggest you do not re use the bolts pictured in 3rd picture on original post. One is not even a starter bolt, no knurled shoulder. GM part or AC part number 15544950 is what you want. I usually use new bolts whenever I have to replace starter, as they can get bent, and have often been over torqued.

I completely agree, the torque and extreme shear loads on the bolts cause them to crack and eventually break. I replaced mine three years ago when i first got my truck along with adding the support bracket. This spring I reinstalled the starter after some unrelated maintenance and one of my bolts snapped. After inspection the bolt was cracked 3/4 of the way through. It's possible it may have been a "bad from stock" bolt but I'd consider changing out the bolts as PM every couple years either way.

 

[cucvrus]

If you need a longer starter bolt for the starter on the 6.2. May I suggest a HMMWV starter bolt. They are longer and have the knurling on them. If you need one send me a PM I have a few new ones I bought in error for CUCV's and found out they were longer. I was able to use 4 last year on HMMWV projects. Take care have a great day.

 

[royalflush55]

If you install a flex plate backwards you can have problems like is being discussed here. The center hole always has a manufacturing burr that can NOT be installed towards the crank. The smooth side must go towards the crank to mate correctly. I have never had to enlarge any hole for a GM flex plate to install correctly. I hope this might help.