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12-02-2006, 09:28 PM #1
I have a buddy that wants me to tig up a crack in his engine case and I have a few concerns I was wondering if I could get some tips for from the experts.
-What tungstun do you recomend (I have a large Ceriated rod I was thinking of using)
-any baking needed to get oil or residues out of the metal?
- I am a little worried it will need to be line bored after this from warping, is this valid?
-Any other tips?
12-03-2006, 08:28 AM #2
I welded a shovelhead a few months back with my mig and spoolgun. It had been degreased so it was clean. The alum welded great. Not sure about the boring, depends where the crack is...Bob
12-03-2006, 10:14 AM #3
I was taught to use pure tungsten for aluminum. I never used ceriated. However where I worked we actually used thoriated 2%. It worked. As far as lubricants in the metal you can heat up with a torch to bring out lubricants. Carefull it doesn't melt on you.
I have welded crank cases with just solvent cleaning with good results when it was good aluminum. Warpage if it is a large crack could be a concern if it located where you have a fitup. Goodluck.
12-03-2006, 03:35 PM #4
It likely will at least need the mains line lapped, but used motors usually need that anyway even without welding. Talk to a shop that specializes in HD bottom ends, it requires equipment the average shop doesn't have.
12-03-2006, 04:45 PM #5
What model welder is it. That deterines the tungsten type.
12-04-2006, 06:26 AM #6
I've done a few of these, shovels, sporties too.
As a matter of fact, I've done my '72 shovel twice- a learning curve I hit face first when I did the double-plug Dynomax ignition coupled with the NO2 bottle. Not once, I learn slow. Ask me about nitrous ring clearances and how the lower end blows out!
Thoriated electrodes work the best.
Those cases have to be clean. Clean them another couple of times after you've baked 'em, degreased 'em, and cleaned 'em again. The pan had good castings, not full of voids like the later shovels and sporties, but they have to be clean.
Are you planning on using the original casting that broke out or one of the replacement casting inserts they've been making for 20+ years? I can't recall now, but there's an outfit ( they're in E-Z_)that has lower ends that match up to the blowouts after you machine off the ugly stuff.
I'd turn a shaft with the right bearings on it and assemble the cases with the shaft installed. Tack weld it first into position, making sure the shaft still spins freely. If it binds you've got to back up 1 weld and redo it so it isn't pulling. This is what I did with the dozen or so I've done. If you weren't on the left coast I'd run my line-up shaft over to you, it makes things a bunch easier.
After welding you just need to give the bores a lick to clean and you're lined up.
Hope this... makes it as clear as mud.
12-04-2006, 11:26 AM #7
N2O on a 72 shovel huh? I bet my 72 FX would love a hit of the sauce! But I am pretty sure my piston ring ends would be butting like something fierce though. Maybe next rebuild I will set it up for that.
My machine is a Miller Syncrowave® 250 DX
It is an original casting from 1955
I thought you could really only use Thorigated for thin Al (red stuff), and even then it was better to use pure, ceriated, or lanthniated.
I like your idea on spinning the shaft to see if it binds, I think I am going to make a set up so I can do that.
Here are some pics of the case.
[ 12-04-2006, 03:46 PM: Message edited by: 352Ford ]
12-04-2006, 11:15 PM #8
Oh hell, that's not as bad as I thought the problem was. I figured, knowing what I've seen in my past, there were going to be a couple of good- sized cracks, or even a portion of the casting missing. Don't ask me how I know. This is why I'd asked if you needed one of the inserts.
It looks like this is a good candidate for your die grinder to relieve some of the metal so you can lay in a pretty good bead. I'd get in on both sides of the crack, on both sides of the case, and cut it back a little bit- but I'm sure you're hip to this already, working with the welder and all.
That's a quality casting- I'm not picking up any visible porosities from your pictures, so that's going to make your cleanup and welding a bunch easier. Still, cleanliness is godliness and a good, trouble-free weld here. Can't stress this enough. Tapped holes are always a bitch to redo, especially if the previous repairs have been a combination of RTV, threaded inserts, JBWeld, and whatever else mixed with oil. Again, don't ask me how I know.
Make yourself a lineup setup, and let it be known that you've got 'em. You'd be amazed how many problems like this there are out there. And hell, you're on the west coast, so we won't be stepping on each other!!
Rings aren't the only thing you'll need to think about. Among other things to consider are, in no particular order- (just how they failed in my order!!!) piston to jug clearance, serious valve springs, cam, fail-proof ignition retard, among others. If your're going to double plug the heads,(EASY) you've got to get the right coils and go with the single fire ignition. Bet you've got that ignition already, though. Best single investment for a shovel. One thing that's great is a lot of people have done a lot with NO2 now, where back in '84, there were only a couple people sick enough to think about this, much less try it. Like I said earlier, I blew a couple three motors trying to get the setup dialed to the point where it is today.
I've always used the thoriated 'trodes in my work. I work a small 'pool' down the crack, it's just been my experience that I want to work a small, thorough weld rather than just blast a huge pool and have the workpiece "sink" around where I'm working. Your technique may be different and you may be a better Al welder than I. All I can tell you is what suits my particular style.
12-04-2006, 11:53 PM #9
352Ford - That crack looks bad to me because it runs up to the cast in bearing insert. The welding may loosen the insert in the casting. I can't tell you how to keep that from happening, I'm not that good at it, but I can warn you to look for it afterward, and if you can detect ANY looseness(solvent seepage under pressure, etc.), the insert needs to be replaced with a shrink in/bolt in repair for the motor to last.
12-05-2006, 12:30 AM #10
If you're worried about distorting the cases, you can make a torque plate out of 1/2" or thicker plate steel, and bolt the case down before you weld it. Just do lots of tacks, use pre-heat as well.
12-05-2006, 02:26 AM #11
Yep for sure 55, first year of Timken left main.
You certainly have a serious problem with it cracked into the main.
Not a welder myself. I send these out for that. However the metal is very pourus, contains sand and oil.
The cases will require extensive precision machining for it to actually hold together as an engine.
This requires the case halfs to be refitted with the final line lapping with the Kent Moore tool as mudflap pointed out.
I have been doing this for over 30yrs and it is not easy. Requires an extensive capitol investment in tooling. I actually use a Moore jig borer with a 5" Wohlhaupter facing head to deal with this very problem.
I will point this out, the cases are aligned by the two centerless ground studs at the two bottom locations and one between the cylinders. however you dont want to attempt to weld repair the case halfs held together using these.
Bolting them to plates or any other nonsense will not help. A experienced welder who can weld repair casting will know what to do, then an experienced machinist in this area can take over, may be helpfull to be Milwaulkee factory certified on top of that.
Otherwise maybe I dont know what Iam talking about, "how much money you got"?
12-05-2006, 11:15 AM #12
If available, I would use Dylanol (sp) to clean up the case before inspection, machining, and welding. That's the way most shops clean something is by passing it from worker to worker - hoping that a little rubs off on each worker along the way.
The case, although intact looks sprung. Like others has said, even if you weld it. The bearing retainer is not going to be tight. Your best bet there is to find out where the centerline is at and make a jig and weld it on the jig - mounted to the table of the machine that you are going to machine it on and then weld it a little and machine it a little at a time to keep it from warping even more.
Then machine out the bore to the proper size before moving anything. Probably a spool gun wouldn't be bad. Because you could add the filler metal quicker than what you could with a tig machine. That would keep you from over heating the part and causing more warpage.
But the other good point was to find someone that is HD Certified to repair this for you.
Unless you have the blueprints for this part and there is witness marks on it. How are you going to be able to determine centerline? It might end up looking like something from the shop I worked at. The only difference between when it came in and when it left is that when it left it was shiney (sp).
It would be real easy to mess up and real hard to fix once you mess it up. Why not ask one of the forum members - that seem's to know what he is talking about to fix it for you - at cost - shop rate + expenses.
1955 was a long time ago, and I doubt if you are going to be able to replace it for as much as someone is going to charge you to weld it!
Keep the NO2 in the Dr's office where it belongs!
By the way - does anyone want to buy a 4L60E transmission for a 2002 Avalanche? I have two of them. One with no 3rd and 4th gear and one with no R, 2nd and 4th! "I guess I can't talk about abuse either"... LOL
[ 12-05-2006, 09:06 PM: Message edited by: Hammer n Chisel ]
12-05-2006, 12:35 PM #13
I will be glad to help you through this situation with with what I know.
The welders that do this do it with tig. dont try to hold the case down when welding, this will only cause problems. Just weld it and all the warp will have to be removed in machining.
the left main has a cast in to the alumininum, cast iron insert. The insert may be broken though as well, it mostlikely will have to be cut out and a new sleeve put in after welding.
Being that this is a 55 and it being very unlikely to find good replacement cases, it is only feasable to repair if, this is an original bike.
If the bike is a chopper or otherwise not the value of an original, Replacement S&S cases would be the best option.
12-05-2006, 01:09 PM #14
i used to do a ton of cast aluminum parts, and more than a few harley parts.
as previously posted die grind out a vee to prep the weld
preheat in a oven to 500 degree's F. this is very important, as it relaxes the aluminum a bit and 90% of the expansion of the cast will happen in the first 500 degree's.
use tig or mig, have done both, pop out of the oven and weld up, put back into the oven bring back to 500 degrees and let cool slowly.
sometimes the weld will show porosity, from oil that came up out of the cast, if it has any, grind it out and do it again, you won't have any porosity the second time.
for an oven i cut a 55 gallon barrel lengthwise to make like a bbq pit, and inserted a rosebud in the end, used a temp stick to get the temp righ, lift lid, weld, close lid and reheat..
if you don't preheat many cast aluminum parts will crack upon cooling, often much worse than the original crack.
12-05-2006, 11:14 PM #15
A temperature stick is + or - 10% which equals 50 degrees at 500* F.. Yes it is better than nothing at all.. But it is easier to just pop it into mom's oven and crank that sucker up to 500* F and let it back for a while.
My concern wasn't if you could or couldn't do it. It was that the case was sprung and that unless you could compress it back to shape. The distortion in the case from the damage would move the centerline of the bearing.
Timekin bearing inspection is a speciality of mine and unless you have it in straight - it isn't going to last for any period of time. Probably breaking the case beside the weld. Since the weld is usually stronger than the base metal.
Yes you get a lot more control with a tig application. But you can't feed in the wire as fast. I would worry more about using the proper gas.
12-06-2006, 12:23 AM #16
The Timken bearing is going to be a problem as the case appears to be broke through its insert.
The general thing to do is cut out the insert. Weld the case and build up the area where the insert was located.
Its also very probable that the right case is twisted also as the damage to left case took a lot of force. I would guess that a primary chain broke and balled up causing this damage.
There are for sure many ways to remachine these cases and over the years I probably tried most.
I finaly settled on using a jigborer.
since the left case is in bad shape, I would start with the right case, aligning the rear cylinder surface to the X axis at the same time using a precision ground plug and test shaft in the right main bearing to true the Z axis to the jigborer, then lightly face the right case mating flange to its shoulder with the Wohlhaupter facing head.
The left case is then faced and the cases placed together with the 3 locating studs and other bolts.
With the right case fastend down and located and the left case on top the bore for the timken bearing can be started. this will provide a reference for the further machine work nessesary.
It will be very handy to machine the other surfaces on the cases for further fixturing as these are first being trued up.
the jigborer is ideal for dealing with this as the machine is always true "if its a good jigborer"
The kentmoore HD line lapping tool pilots off the left case timken bearing and it will be apparent if alignment is achived by the repair as the right race will need to clean up within the range of oversize rollers.
I hope that is clear as mud.
12-06-2006, 05:31 PM #17
Thanks guys for the great info
12-06-2006, 11:17 PM #18
I would certainly do some preheat as suggested above. The only negative issue that I see is that the crack runs up to the cast-in steel spider insert that holds the left main bearing. Those are cast in and are non-removeable.........
When you start on the outside, it would be good to have the other side of the crankcase so that you could bolt them up together. This might help to minimize warpage while it is tacked up, You could then open it up again and weld the inside.
You need to consider what to do when you approach the steel with your TIG torch. It's not going to be possible to weld completely up to the steel........I'm not sure how you would handle that.
The above suggestions regarding jig boring machine work are excellent but beyond my knowledge. They also sound very expensive as they should be for good work. By the way, I've seen a set of those early crankcases go for as much as $2,500 with a title in good condition so you have something to shoot for.
I've welded a few Knucklehead motor mounts, Panhead exhaust stubs and motor mounts, Shovelheads, , primary cases, transmission cases, etc. One good thing is that the metal on the early ones like you have is almost pure aluminum and will weld very well, up to the steel insert.
Good luck. Let us know how you do.
12-08-2006, 02:01 AM #19
Ditto on Newman's post. As I said earlier, this is one of the good castings that will weld well. A heck of a lot easier to work on than the AMF castings of the 70's-80's. Like yours and mine.
I fully shim out my line-up shaft to the motor's crank, including any included shims. Hopefully, you have the other case and crank in your possession, you can get your dimensions from the crank and bolt the halves together, starting with the outside tacks.
Am I seeing cracks around the bolt holes also? The pics are looking like that, and these are going to be the ones that will require the cleanliness thing going on, as mentioned before.
You can do this. As mentioned in several posts besides mine, these are done pretty regularly by talented rider repair guys, who don't have megabux to pay "certified" mechanics.
I've gotten 35,000 on my last weld-up, which was the third on this motor- as I mentioned, I went through some growing pains experimenting with stuff. The motor is strong, and I bang the NO2 more often than an old fart should.