[Itsnotatumor]

I had my 58' Triumph cases welded by a shop that I had assumed knew they needed to be in a jig or in the least clamped down. I guess not. Now I have a timing case that has a .020 gap between the case and the cover. (cover is flat). I also saw a few shops suggest putting the case (all bolted together w/timing cover) in an oven. Has anyone tried this with pre unit cases before? Im guessing around 250˚ ?

Any suggestions?

 

[JasonMcElroy]

Uh oh.

To my thinking repair would mean realignment of all shafts that traverse both case halfs (cam bushing, crank bearing races / bushings), redecking the cylinder spigot and refacing the timing case gasket surface. That's a lot of work, assuming you can do it successfully. I'd be inclined towards finding other cases.

Once they're warped, I don't think heating is gonna return them to prior state.

Jason

 

[WhizzbangK.C.]

Where on the cases was the welding done? What was the original failure that required welding? Why were the cases not bolted together during welding? How well do the case halves align? Do you have any pictures?

Like Jason said above, if they're warped much at all you might be better off finding a new set of cases. There might be a fix that is possible, but it might take more time and effort than it's worth unless there is some compelling reason to save that particular set of cases.

 

[Itsnotatumor]

The welding was done on the stripped and broken threads. In the pic where my finger is pointing, that is where the .020 gap is. (In between the timing cover and the Rt side case.

 

[Itsnotatumor]

Where on the cases was the welding done? What was the original failure that required welding? Why were the cases not bolted together during welding? How well do the case halves align? Do you have any pictures?

Like Jason said above, if they're warped much at all you might be better off finding a new set of cases. There might be a fix that is possible, but it might take more time and effort than it's worth unless there is some compelling reason to save that particular set of cases.

These cases are a matched set and the numbers match the frame.

 

[Rick_Bee]

Build up the low areas with weld and resurface. Use low temp rod?

 

[WhizzbangK.C.]

These cases are a matched set and the numbers match the frame.

Rick is correct. When welding a sealing edge the weld needs to be run out along the edge to leave enough material to machine it all back down flat. I've had to go back and add weld a few times on some repairs till it all leveled out. On that particular case repair, I would have machined up a support to exactly match the distance from the sealing surface on the case half and the timer mount surface, and then clamped the whole thing securely to my mill table before welding. I'd have then located the cover bolt positions with the DRO, cut out the damage with the mill, weld and machine back including drilling and tapping the holes without moving the case from the machine table.

 

[Rick_Bee]

I think this may have been due to shrinkage/warping, lack of pre-heat, poor welding technique.
Welding on this old junk is an art form, a lot of technique and a little luck!
Unless your welding on an old Pan case (your luck just ran out)..

 

[natez1]

Looks like they left a little material on the repair area. If it was me I'd transfer punch the holes, drill and tap, then file it as flat as I could. A good gasket would take up the difference or put a little aviation sealant on it to help.

 

[magnum45pete]

I know this will not help you now, the damage is done, but for future information, when welding on crank cases or covers it is best to assemble as much of the motor guts (cams Crank, oil pumps and cam cover etc) as possible,

as the internals act as a heat sink and disepate the heat and having the cases bolted together will stop warpage, plus pre heating slowly in an oven,
a few years ago, I built a 45 Magnum where there is a LOT of welding to be done, firstly on the barrel base stud holes for repositioning for the Sportster cylinder bolt patten, and welding the right side of the deck also for the cylinder's to fit and had to weld on welds to build it up close to about a 1/2 inch before machining back to where it needed to be, I did the welding slowly, one bit at a time, bit by bit over 2 days so as not to over heat the cases,
when finished and disassembled prior to vapor blasting and final rebuild, there was no warpage whatsoever,

 

[JasonMcElroy]

What Pete said ;-o

Also, after seeing the pictures posted it might not be as bad as we thought before we saw where the welding was done. Most of it seems to be out on the mag/dyno nose and not in the center of the case where the pinion and cam shafts run. You just might get lucky taking the cover flange surface to level. Definitely check the alignment of the mag/dyno shaft and gear engagement to make sure it's not binding with the other timing case gears. It will be destroyed quickly otherwise.

To be really careful, check the cam bush (closest to the weld) alignment with other case side as well.

Jason

 

[richbob]

And maybe run the fibre mag gear

 

[Ratso]

Ah that's good thinkings, richbob. (I'm still in the dark as to why a builder would replace that soft sacrificlal part with a harder version.)

Hope Jason's post cheers up the OP; it certainly did me (cautiously). It was sickening to read that the arguably ruined cases were numbers-matching.

 

[WhizzbangK.C.]

Ah that's good thinkings, richbob. (I'm still in the dark as to why a builder would replace that soft sacrificlal part with a harder version.)

Hope Jason's post cheers up the OP; it certainly did me (cautiously). It was sickening to read that the arguably ruined cases were numbers-matching.

I don't think they're actually ruined yet. Like I said in a previous post I would make up a standoff to go from a mill table to the back side of the mag mount flange to establish it as parallel to the rest of the case, and then mount the case and standoff on a mill table (or other known flat surface, I lean toward the mill table because of the east of fixturing things firmly with the t-slots). Check that it is still straight, and if you find it warped get it hot enough to start welding and then snug up the fixture to push it back into alignment before completing the weld. Note that every single repair on cases is a bit different, depending on where the damage is and how much welding needs done. In this case he's lucky because it's in a spot that is relatively easy to correct if something did move.

One little trick I use when dealing with a sealing surface is pretty counter intuitive. Everyone knows that you have to clean all the oxidation from the surface of the metal before starting to weld. This is absolutely correct in order to get proper penetration and fusion and to prevent porosity and inclusions. But, I find that if you leave an area of oxide near the weld, and work the bead out toward that untouched area, you can get the metal under the oxide to melt while the oxide is still intact and actually get the surface at the very end of the weld to raise up under the oxide layer when you put your last dab of filler in. That gives a weld that is proud of the surface making it possible to machine back to the original level and usually not have any dips to create leaks. It doesn't always work, but when it does it makes life easier.

 

[joe49]

BINGO on under the oxide layer.