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Starter bolt holes on block cracked! Help.

dbrannon79

dbrannon79

I'm getting there!
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Well I think I just found what no truck owner wants to ever find on their truck! Friday afternoon when I went to head home from work, went to fire up my pickup and she sounded awful, the starter was grinding! Never the less she started and I made it home, went to pull the starter to see what happened and low n behold I see a huge nightmare :jawdrop:. the outer bolt hole had once been broken and someone had welded up the cast and re-threaded with an insert. the other hole also has a small crack across it. Of course when pulling the starter I noticed that the bolts were bent as if the old bolts were re-used and over stretched, thank God they didn't break getting them out. I ran to the local auto parts, bought some new starter bolts and carefully re-installed the starter, said a few prayers and attempted cranking her up! she started fine, with even less noise than when I bought the truck, since I re-shimmed the starter and made sure I installed the rear bracket which the previous owner had left in the tool box! what a relief, but I know this is far from over, I will need to find a permanent fix for this or I will have to cut my losses and start over!

I did a little searching online for a solution and found this video from you-tube which shows an adapter plate to convert a 350 Chevy to use a three bolt starter. would this possibly work on a 6.5? or is there something like this made for this type of problem?

 
Nope. Gasser uses different flex plate tooth count. You can just use a gas flex plate or flywheel because it is part of the balancing for the engine.

You need to have the block welded up, drilled and tapped out. Don’t go for the cheapest person to do it, get the best. That’s because is the holes aren’t is exactly the right spot - you have to start over. Many blocks end up in a trash can over this sadly.

Once fixed- get a powermaster 9052 starter on there- far better unit that starts the engine much easier.
 
Will L. said:
Thinking about it, maybe you could- if the diesel starter can interchange with the gasser starter cup. Hmm...

So back to a solid I don’t know...
Click to expand...
I figured I would have to get a custom starter made, or at least see if the nose cone would be interchangeable. as for the flexplate, I'd leave that alone. I wasn't sure if the bell housing bolt pattern was the same between the 6.5 and the 350's. for a 6.5 engine with a manual tranny, does the starters mount to the trans bell housing or still mount on the block?
 
Your block is "scrap metal". You see the PO bought some time by "fixing" it before, well, time's up. Sure you can limp it by, but, the real fix is simply another block. With feeling: It's a 10 HP starter that makes more torque than your lug nuts take. Not going to stay on a repaired block real easy: as you just found out. The brace will help, but, isn't the fix needed here and wayyy too late.

Used engines are hard to come by in usable shape. Rebuild costs add up quick. So is the truck worth dropping a new short/long block in it? And let me qualify it with Hertz is dumping their fleet cheap due to their Bankruptcy.
 
They all mounted to the block just like the 6.5 except that 3 bolt when the small block first came out.

Is the small block and the 6.5 flywheel the same outside diameter is the question. If so and you can get a nose cone- that should solve it. But moving the trans back to get that in there- then the longer metric bell housing bolts needed.

IF and I mean IF... the flywheel is same OD and you can find a nose cone- yeah it COULD e worth a shot.

I would really find a welder and get a price first though. A few sticks of muggy weld and you being there to do the starter if he doesn’t want to play mechanic- and it might only be $300 or so. But overhead welding, overhead drill and overhead tap-in tight area means a feller might charge double just cuz that is a pain in the neck job.

I welded up a few and they never had any issues afterwards. But I was young and sprightly then. Haha

I wouldn’t chuck it. Very worst case scenario is pull engine to have it welded and tapped upside down on a pallet.
 
Ok, did some checking. the bell housing bolt patterns are the same for the small block Chevy 5.0 (305) on up to the 6.5 diesel engines. also the flexplates are all the same diameter 14.13 inch according to Napa. each have a different option on the number of teeth but that wont be a problem since I would stay with the same flexplate I have. As for the starter nose cone, I gave a hard look at the 6.5l starter and one from a 350 gasser, they look to be interchangeable. I'm sure the local starter rebuild shop could build up a starter that would handle the torque needed for the diesel engine if the nose can't be swapped. This kit I found has all the spacers and bolts needed to space the flexplate out to accommodate the 1/4 inch plate that would be sandwiched between the block and the tranny.

here is a link to one site I found selling this kit
https://www.classicchevy.com/chevy-...matic-transmission-1955-1957-57-132290-1.html

For the price this might be worth a shot, but then again it might be a total waste of money and time! I'm still looking for more info on this type of repair though, wondering "IF" this will work, how well it will hold up over time vs finding someone to weld/repair the block. the other potential problem could be that there is no shimming the starter for the gears, so everything has to be right or else!

I guess I need to find some classic car builders out there or someone who might have done something like this to know if it's as easy as just bolt n go or not. I just hate it when all seems to go well buying my first diesel pickup and it bombshells on me with this kind of trouble 😭
 
Welding up the starter mounting bosses on the block is barely a 50/50 proposition that it will work. Properly welding cast iron is a quickly becoming a lost art form. It is NOT just a 'put the right welding rod in, crank up the arc welder and go for it' weld. The block is cast iron, it will crack from the intense localized heat from the welder if not preheated to over 500°F before welding, then the part MUST cool slowly (not air cooled) by packing it in hot sand and allowed to slowly cool over a period of a couple of days to prevent thermal shock cracking. There are only a few welders out there with extensive experience welding cast iron left any more. Also, you are looking at doing this on a bare block outside of the truck if you want to do it right. Then, there is still the issue of the drilling and tapping of the starter bolt holes in the exact locations.
 
Well I'll be. Fancy that newfangled invention. I don't weld for a living, just for necessity. Call me Old School, but my description was the only method I knew of.
 
dbrannon79 said:
I just hate it when all seems to go well buying my first diesel pickup and it bombshells on me with this kind of trouble 😭
Click to expand...

It's a 25 year old truck: what do you expect? It's also a throwaway engine the military treats as expendable.

How about some pictures of the prior repair? The prior repair IMO is being overlooked as more trouble to this possible repair. How good or bad was the prior repair and how much damage is there now?

As it's working NOW it may be best to leave it till it fails again and the address what to do then. What's the budget? A knock off China cast block may be a better option than attempting to weld this mess. Nevermind what else is cracked in this block: main webs, heads, etc. Even a gas conversion may be cheaper out of a junkyard.
 
At the moment it's still holding up fine after installing new bolts and the missing rear bracket. As for pics, I didn't take any nor do I want to remove the starter again since it's working. The repair I saw was made on the outer ear where someone did some welding and used a heli-coil thread insert. the inner bolt hole threads look fine but you can clearly see a small crack across the open bolt hole. I did try to get a good look at that crack and it looks to not go very deep where it's not causing any issue with the threads in the block, but that is still an unknown. when I reinstalled the starter, I didn't try over tightening the bolts at all! I used a long handle ratchet and tightened them by feel as many people do, so if anything they are under-tightened but secure. Figured I would slide under the truck and re-check them from time to time. the worst thing would be to reach ether the specified torque or over tighten and the thread insert or welded area pull and break. I did take note that the inner bolt hole has about a 1/4" of extra threads that the bolt doesn't reach and have thought about getting a slightly longer bolt there but I am hesitant because the starter bolts have a machined fit through the starter not to allow any misalignment and a standard bolt could possibly allow the starter to shift slightly.

it's a shame that GM didn't design these starters and blocks to use three bolts. this one uses the diagonal bolts, if it were designed, they could have had two bolts on the inner side close to the oil pan.
 
They did design it for 3 bolts. Instead of 3 all on one end, 2 at the high torque end and 1 for the weight. But people don’t like to reinstall one and that is where the problems start.

Many large diesels use the three at the torque end like the original sbc in the video- but myself and other’s that wrenched on them can attest to their own world of issues. 12 point bolt heads to try fitting them in the tight areas. Required clocking designs because of minor changes in solenoids availability means ‘custom’ fitting often needed. Then on trucks that get beat up used on rough dirt roads- they break so in the end they stick a mount at the other end anyways to deal with it.

I would say, ask your insurance about free towing. Then just start saving cash because at some point, it will go. But who knows, it might give up in July of 2030!
 
I know that when I had the starter off, there was only two bolt holes like the photo here. if I could get my hands on a nose cone or an old school starter with the third bolt, I would defiantly try to attempt drilling and tapping that extra hole in the block help prolong the inevitable!

(photo is of a 6.5l I found online, not mine of course! but if you look at the bolt hole thats being pointed to, mine has a through the hole in the ear, the outer was broken off and re-welded.)
SMB Chevy Starter mount.JPG
 
in my last post I left out the word "cracked" in the picture caption, and can't figure out how to edit the post!


Here is a site I found that sheds some light on the three bolt starter design, but I see there is two different bolt patterns. now I am wondering if the nose cones are interchangeable and if so which would be best to try if I were to attempt this modification on the block, and if it would be worth the trouble. I would guess I would need to go with the pattern for a starter nose that is readily available in case the nose ever breaks or wears out in the bushing area. once it's drilled for one, I wouldn't be able to use the other if I screwed up!

http://rmcavoy.freeshell.org/starters.html
 
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