Corvette C5 starter mount failure - welding aluminum engine block?

[Baysailor]

I thought I would solicit ideas from you folks here:

I am helping a friend of mine with his 2002 Corvette C5. This past Monday his wife got in and started it up. It started, but she said it sounded a little funny starting. She backed it out of the garage, but remembered she needed something inside so she shut the car off and ran inside. When she came back out and tried to start it, the starter just made a grinding noise.

I told him I would help take a look at it. On Wednesday, we crawled underneath to take a look and could see a crack in the starter housing. Initially the thought was "oh good, the starter housing cracked and the starter shaft/gear no longer aligned properly with the flywheel ring gear." So we proceeded to remove the starter (you have to drop the down pipes to access it). While removing the bolts that hold the starter, a hunk of metal fell out. At first we thought "oh, this part of the starter housing", but upon extracting the starter it became obvious this hunk of metal was the outer part of the ear/flange/support that the starter bolts to. To make matters worse, this is flange is the PART OF THE ENGINE BLOCK. The block is cast aluminum. It is amazing to see this much damage. Cracked starter housing AND broken engine block casting. The starter is well protected and would be very difficult for it to have ever been struck by an object when driving.

In searching the Corvette forums, there appear to be a couple of others that have had the same thing happen. At least one replace the engine and another had theirs welded (I think this was on an older Corvette that had a cast iron block). So far we have checked several local places (Corvette specialty shops, machine shops, dealers, etc.) and the opinions seem to lean more toward replacing the engine with a few saying it could be welded. Unfortunately, neither option is inexpensive as with the welding, they are saying the engine would have to be removed to get to it. With welding, I also worry about him paying for the removal and replacement of his engine only to find out that the "fix" didn't work. The starter only has two bolts holding it (there is no back bracket or other support). How good of a weld can you get on cast aluminum like this?

Would appreciate any recommendations that anyone could offer!

JB Weld???

Picture of the piece that broke off:


Picture of the flange where the starter mounts:


Picture of the starter with cracking visible on the housing:


Picture of the starter with casting perched where it would be when mounted up:


Picture of another person's Corvette engine (removed from car) with same issue:

[tesprit]

JB weld isn't going to cut it in this case!

That broken boss and the other crack can be welded, but that isn't going to happen with the engine in the car and possibly not with the engine fully assembed. Once everything is welded, you will then need to have the boss and block precisely remachined and the boss rethreaded to accept the starter bolt. I'm afraid there just isn't an easy or quick way out on this one.

On a positive note, this damage can be repaired by welding and it will be a solid repair.

[Mr. Oz]

Regardless of how it's repaired, have the ignition system thoroughly checked paying particular attention to the crankshaft position sensor and ignition timing while cranking. I have seen problems with this putting extra strain on the starter and mounting, usually resulting in a broken starter nose or worst case a broken block like you experienced.....my 2 cents.

[SweetDaddyD]

....Like a rock.

(you knew someone was going to say it)

[antinym]

yeah, you can weld it and it will be as good as oem, and how good was that? I'd guess it'd cost around $500 for a good machine/welding shop to repair it. On the other hand what's the cost of a refurb block and a rebuild. Either way, you'll have to pull the engine.

[rob13572468]

what about fabbing up a 90 degree bracket that attaches to the bolt hole that is 2 inches above the broken mount.. you would have to cut away a small section of what is left of the original monting surface to make room for the thickness of the bracket but it should work as long as the stresses arent that great on the upper bolt...

[Addictedto]

It CAN be welded, I have aluminum race motors that have had multiple "windows" repaired. Its one of the main reasons we use aluminum blocks. I have seen some in chassis repairs you wouldn't believe. Someone who is a VERY good TIG welder can get into some really tight spots and it can be welded overhead.

[turbophil]

That would be quite difficult to weld especially with all that oil around the area. It would have to be cleaned really well and the bits and pieces conditioned for a good weldment. Engine would have to come out if you expect a weld to be as strong as the factory casting was.

That still sounds cheaper than replacing the whole engine though...

Good luck,

Phil

[Vulcan Grey]

Even if it can be welded... Should it?
If that broke, then what does that say about the rest of the casting?
That block may just be a bad casting... Though maybe they all are!

[NJ 666]

Damn, being a GM fan I know I'm going to get flamed on this. There are a handfull of gen III aluminum blocks that did this. On one occasion a customer tried to put a starter in himself and snapped the corner off. The tech working on it used,believe it or not, Permatex 2-part metal epoxy and reinstalled the broken piece. He let it sit up a day,drilled it,tapped it, installed a longer bolt that was torqued to spec, and used a nut and large washer to help secure it. 4 months later it's still holding. On one site they said A/C Delco has some sort of bolt kit or support bracket to help eliminate this. I would maybe install a stud into the repaired section with a locknut on top of it. This way when installing the starter the block is only having a radial load not a torsional load applied to it(for the most part)

As far as the ignition issue. It's possible but I doubt the ECM is putting that much timing into it during cranking. If there was a failure with the CAS the engine prabably wouldn't fire because the CAS and CMS would be out of phase and would more than likely set a CEL. But who knows?

As far as the quality of the casting. Earlier aluminum gen III blocks did suffer from some core shift but that was corrected by 2000 I believe. There are plenty of LS1's making well over 500hp N/A and over 650hp F/I so the rest of the casting should be ok. But, this is a perfect excuse to convince the wife you need a H/C LS3 swap.

[lancer360]

I'll second the opinion that it can be welded, but you need to find a good shop that knows what they are doing. This isn't like welding new aluminum. Aluminum castings are porous so it will get contaminated over time and will take some treating to get it cleaned up enough to weld. From the photos, it would require the block to be pulled.