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Found pictured cracks in my aluminum bell housing. The machine shop that is rebuilding my engine seems reluctant to want to weld these cracks and indicates it will be quite expensive (couldn't give me a price and feels he won't know until he starts fabrication). This shop has an excellent reputation nationally. I was surprised and thought some simple welding was all that was required. What do you guys think? Should I just find a shop that does nothing but welding or bite the bullet?
No reason that bellhousing can't be successfully TIG welded. Looks like someone may have tried to pull a transmission up to the block with the bellhousing bolts?
They appear to be all the way thru the metal wall. Also appears stress from starter torque when cranking started the cracking. At this point you have two reasonable choices:
1. Find a new bell housing.
2. Get price from Jerry McNeish (or other very qualified aluminum welder) to do a complete weld repair. A good TIG welder should be able to do, but initial cleanup and prep + weld time may make the job cost prohibitive.
Now if you have a best friend that welds daily for the chemical for nuclear industry, then............
Larry
Last edited by Powershift; 05-20-2019 at 06:15 PM.
If you are not going to weld it yourself, I suggest you try to find a used bellhousing that isn't cracked. By the time you pay someone to grind all of these out, do the preheat prep and then try to post finish it so it looks acceptable, you will be better off buying a bellhousing. With the crack going from the pivot ball hole to the tranny location hole, you would probably need to prep the weld there also to allow facilitation of the transmission.The issue with this part is, that I'm sure there is oil and grease inside the crack and pores, and this will have the tendency to pop the welds. To open the crack out enough to get the years of grime will take a lot of material away. This is another possible reason why the shop is leary is they do not know if someone tried to clean it already. If they used items like brake cleaner, then the volatiles are toxic to the welder.
Last edited by playzwithcars; 05-20-2019 at 06:28 PM.
While the cracks can be weld repaired (not the easiest thing, but can be done), there may be a residual problem with this bell housing - that of being out of factory measurement specification due to the stretching that resulted in the cracking (and I think Mike might be right - looks like attempting to pull it tight to the engine using the bell housing bolts - always the wrong thing to do) which is not assured of being corrected by welding. A stretched bell housing can result in a badly misaligned transmission input shaft to pilot bearing mating fit up. I would have a professional machinist measure it against the original GM drawings, or a known good bell housing - or at least confirm that the front and rear mating surfaces are parallel. Additionally, on the off chance that the bell housing is parallel but "racked" I would want to use a precision run out gage to check axial runout once assembled.
I had very similar cracks repaired in my 68 GT500 bell housing. I ground and cleaned them, then found a welder who didn't hesitate to weld. I, however, made no attempt to conceal repair. That may be what makes or breaks a replacement. He charged me less than $50 to weld.
While the cracks can be weld repaired (not the easiest thing, but can be done), there may be a residual problem with this bell housing - that of being out of factory measurement specification due to the stretching that resulted in the cracking (and I think Mike might be right - looks like attempting to pull it tight to the engine using the bell housing bolts - always the wrong thing to do) which is not assured of being corrected by welding. A stretched bell housing can result in a badly misaligned transmission input shaft to pilot bearing mating fit up. I would have a professional machinist measure it against the original GM drawings, or a known good bell housing - or at least confirm that the front and rear mating surfaces are parallel. Additionally, on the off chance that the bell housing is parallel but "racked" I would want to use a precision run out gage to check axial runout once assembled.
I had very similar cracks repaired in my 68 GT500 bell housing. I ground and cleaned them, then found a welder who didn't hesitate to weld. I, however, made no attempt to conceal repair. That may be what makes or breaks a replacement. He charged me less than $50 to weld.
That's certainly cheaper than a replacement one, if they're expensive.
Originally Posted by MikeM
Replacements aren't cheap.
I'm getting that idea. If the OP can get a cheap weld repair, the measurements should not cost much, and there's a good chance it would be in spec or an offset locater pin would make it align, so the expenses of "fix and use" would seem to be cheaper than replacement. Does that pass the common sense test?
Last edited by Easy Rhino; 05-20-2019 at 07:24 PM.
Significant weld repairs (and this one probably qualifies) can distort the metal and screw up precision tolerances. I have fought this many times in the chemical plants. Careful stitch welding by the welder may eliminate this issue for this part, but maybe not. Agree with Rhino that some dial indicator checks and flatness checks should be done after the welding on this part.
The grease and oil in the bell housing cracks will complicate the repair, but again some good prep work ahead of the welding will mitigate the problem.
It's really all about the economics.............so OP should price it out.
If that were my bellhousing, my concern would be the aluminum warping from the welding heat. If it becomes warped, getting the transmission and clutch properly aligned would be a major problem. It might not even be possible.
My suggestion, which the OP is free to ignore, is to have the bellhousing securely bolted to an iron block and to have an iron transmission main case bolted to the trans mounts while it is being welded.
Another option is an aftermarket bell housing,,, it won't look original and I don't know the cost, but you won't have the alignment or welding problem concerns...
I'd play it safe and replace the thing, and carefully inspect the mating surface on the block. If something is irregular there, or something foreign was trapped between the bell and block when the bell was bolted on the last time, it could explain what you're seeing.
Thanks for all of the posts and recommendation. My machinist is a great guy and is honest as you would ever find, so when he tells me there's a problem with something I take it as the gospel. I have owned this car since 1988 and have been trying to improve it (with a tight budget) every year or so. This past November I had a rod knocking, so me and the neighbor pulled the trans and engine as a unit and began disassembly and transport to the machine shop (including the bell housing). My goal for the car is to have a mechanically sound,dependable, fun driver. I'll see what he comes up with but will probably go with an after market or used BH, if repair is not possible.
Thanks
A LOT of good, and valid information above. I have ZERO issues with any of the comments.
BUT, I have had alum bell housings welded. I DO HAVE a dear friend that is a genius at welding alum (which is mandatory).
Two things.
I do feel it can be welded (if done properly by a VERY experienced person who welds alum) and saved.
These housings (TWO, one for 60, one for 61-2) are becoming scarce and quite pricey. At one time, I felt $300 for one was ridiculous, but if it is in good shape, that is not a bad price.
Not only were these open bottom alum housings used on 60-62 Corvettes, but they were also used on full size 60-62 Chevys with a Hi-perf 348/409 (and 63 only 409 cars). So there were a lot of them used.
A LOT of good, and valid information above. I have ZERO issues with any of the comments.
BUT, I have had alum bell housings welded. I DO HAVE a dear friend that is a genius at welding alum (which is mandatory).
Two things.
I do feel it can be welded (if done properly by a VERY experienced person who welds alum) and saved.
These housings (TWO, one for 60, one for 61-2) are becoming scarce and quite pricey. At one time, I felt $300 for one was ridiculous, but if it is in good shape, that is not a bad price.
Not only were these open bottom alum housings used on 60-62 Corvettes, but they were also used on full size 60-62 Chevys with a Hi-perf 348/409 (and 63 only 409 cars). So there were a lot of them used.
I am meeting with my machinist tomorrow to pick up my engine etc. and see what the verdict is about the BH. I have contacted 2 sellers of these bell housings on ebay $300-$450. My car has been out of commission since last Nov. and I anxious to get the re-installation underway. Thanks for the info.
05-20-2019, 05:36 PM
Bell Housing (ALuminum) Cracks
