Topic: Engine case chain damage fixed, mating surfaces now compromised..

[excellrec]

I also have a build thread going but thought I'd post this here where more eyes can get on it.  I had chain damage in the sprocket area of the engine cases on a motor I was rebuilding-


So, I sent the case off to the welder to be repaired-


Now the crack is no longer an issue, but unfortunately things got a little out of hand during the welding process and the mating surfaces were somewhat compromised-


At worst, the mating surface on the lower half was ground down .020".  So now I'm wondering what the wise members of this board think I can get away with.  This was done by a professional welder for free at a close family members shop, so complaining to the welder and demanding compensation for the flaw is not one of my options.  Additionally, I think they did their best and the metal just wouldn't cooperate. 

I'm considering-

Carefully using RTV at the point of the gap (I've lost an engine to an oil jet clog so I'm aware of the dangers).

Putting down some jb weld and placing the other case half on it with a piece of saran wrap between them to create a flat surface.. then just bonding the cases as per usual after the JB weld has long since fully cured.

Getting different used cases and hoping they are an improvement.  Also, this is mid-engine build so a lot of the parts that were in this motor and worn with these cases have been prepped/cleaned/renewed/spec'd, so different used cases would be a serious p.i.t.a. at this stage.

[rhinoracer]

Same thing happened to me. Ended up getting a set of cases on ebay for like 50 bucks. This was like 6 years ago so prices may vary.

[Eddie]

I think I'd try the JB weld as you said...

[excellrec]

Same thing happened to me. Ended up getting a set of cases on ebay for like 50 bucks. This was like 6 years ago so prices may vary.

From my recent searches it looks like it's going to be at least $100 to get a pair of cases to my door.  Then I have to get the studs out.. Which usually ends up costing me around $75 in having a shop weld and turn some off and/or helicoil the threads.  So I'd plan to have to spend around $175 to get cases to the stage these are at.  Then there is also the matter of clearances for the main bearings relative to my current crankshaft being and unknown and some degree of difference in the wear patterns for the shafts and so forth.  Did you have any problems associated with these things?

[kghost]

If its the mating surface........

Take it back to where you had the repair done.

Build up a weld on the mating surface and file it down to fit.

[750K]

^^^thats what I'd do too, especially if the welder is a friend. Show up with a case of beer and then do the filing yourself.

[Retro Rocket]

If its the mating surface........

Take it back to where you had the repair done.

Build up a weld on the mating surface and file it down to fit.

+1, or have it built up machined on a mill for more accuracy...  Its not really a big job...

[kghost]

^^^thats what I'd do too, especially if the welder is a friend. Show up with a case of beer and then do the filing yourself.

Yup. I mean it looks like he did a decent job on the crack.........

[excellrec]

Hmm, I guess I hadn't considered that possible because of the bolt holes around and because the metal was so hard for him to weld to begin with. I suppose I'll ask to see if the welder thinks The metal will be cooperative enough to build up a surface that I can machine down.

[kghost]

4043 rod works really well for that sort of stuff.

If that's not what he used.....maybe recommend it?o

[Eddie]

anybody try this ?
http://durafix.com/

[rhinoracer]

The thing with welding the cases is that they warp with the heat from the welding - at least with mine.

So if you build up the mating surface in one spot it'll warp at other spots.

[iron_worker]

I think JB Weld would be a very solid fix in this case. As long as the surface is prepped properly so it has something to bite into, the JB is allowed to cure fully, and it's carefully filed or block sanded flat. I think it would work well.

Adding more heat from welding could induce more warping as has been mentioned. However, it would be the most permanent/best solution if done correctly.

IW

[754]

Dont try to short cut the JB, make it higher, then carefully work it down. When welding never let the welder take it down for you, if they do insist tell them to leave a 1/16 th.
 Do your tapped holes line up ?

[Vinhead1957]

+1 on 754. Real metal vs epoxy

[excellrec]

Alright, spoke to my stepfather (its his shop) and he said he'll bring it back to one of the welders on Monday and tell them to build it up over the case half surface and leave it.  He didn't seem optimistic about the whole idea to keep welding on the cast metal.  If it does not workout, however, someone was sellin a motor for 120 on Craigslist today, so I could probably use the cases and some parts from that.

[kghost]

Don't get discouraged.....you haven't spend any money yet.

The cases were screwed when you got them. If it doesn't work your not out big bucks

[754]

What I meant was put the JB on higher than it needs to be then work it down.

If you weld more on it, make sure they dont grind it right down...good luck..