Welding engine case

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Welding engine case

Postby ThumpStreet » Fri Oct 09, 2015 6:40 am

My recently acquired 1969 XLCH has a poor quality weld repair L/H side case causing unacceptable primary side oil leak.As of late I've been doing some preliminary engineering in my pea brain as to making a thoroughly proper repair.This brings me to asking advice from members experienced with case repairs their thoughts on the correct filler rod to use with Harley's case castings.I was thinking of using Al 4043 but would appreciate any input as to the best procedure to use to make a correct long lasting repair.
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Re: Welding engine case

Postby sportsterpaul » Fri Oct 09, 2015 4:06 pm

My understanding is the cases are close to 356 alloy. I am told that you can weld in plates of 6061. As to the rod--
http://www.esabna.com/us/en/education/b ... -alloy.cfm

I am sure the experts here will have specific advice. I have never heard of people useing wire-feed MIG, its always TIG.

One thing I do know is you should pre-heat the case before welding on it. Otherwise the case half is sure to bow, and then you have to deck it, and then you start running the flywheels in the wrong position. Kenny Puccio, one of the best welders in San Jose, had a "shade tree" method for this. He would get his oxyacetylene torch and and run pure acetylene, and play it over the case half until it was covered with soot. Then he would set the case half on top of his wood-burning stove. When the soot all burned off, he got out the TIG and did his welds. He did not tell me if he kept it on the stove while he welded but I suspect he did. He then let the wood fire burn out, and the the whole mess would cool off with the thermal mass of the stove plus the cases. I think he told me that bolting up the halves does no good, the idea is to not have any residual stress in the case, not to hold it flat while it cools too quickly and gets full of stress. If you post-heat treat I believe it will take out the stress, but you will still have a bowed case half.

Of course, all this is predicated on how much welding you are doing. If you are filling in a 1/4 inch dot, you might just hit it with the TIG, lets see what the gang says. You do have to make sure the mating surfaces are dead flat when you are done. Feeler gauge and surface plate or a thick mirror or piece of glass works OK. If its bowed, my machinist buddies all had a surface plate with sandpaper glued to it, to get things dead flat-- use a figure-8 motion. Getting the sandpaper glued flat is an art unto itself.
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Re: Welding engine case

Postby ThumpStreet » Fri Oct 09, 2015 5:01 pm

Excellent input from Sportster Paul.Keeping the case's original shape is paramount.I love the preheat and slow cool down method described in Paul's reply.That type treatment keeps all the casting molecules happy which means no warps or future cracking because of the repair.By the way,TIG will be the process used,but you really heightened my focus on avoiding stress risers in the repaired case.I most likely will be using a propane fueled fire box for the preheat and slow cool.Any ideas out there for slow cool times or preheat temperature that would be considered about ideal?Thanks for the reply,great info.
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Re: Welding engine case

Postby dr dick » Fri Oct 09, 2015 9:01 pm

cases are 319alum
4043 is the correct rod.
some pri side case repairs can be deceptively difficult.

i have loads of experience fixing cases.
i should be able to answer any questions you have.
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Re: Welding engine case

Postby Hammie13 » Sat Oct 10, 2015 1:14 am

The wood stove method makes a lot of sense,a friend of mine used a hot plate with a 1/4 inch steel plate on it. One thing he stressed was using a torch and heating the area several times to get the oil to bleed or leech to the surface,then scrubbing it with a stainless wire brush. He'd do this 4 or 5 times,until nothing bled out of the case,then weld it on the hot plate.
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Re: Welding engine case

Postby EKHKHK56 » Sat Oct 10, 2015 5:17 am

The propane Barbie with lid and thermometer built in is nice for consistent measurable heat for preheating and slow cooling of parts. Had good luck putting fins on cylinders like that with my Mig. Or Mamas stove when she`s out...Erik
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Re: Welding engine case

Postby Zaemo » Fri Oct 16, 2015 11:15 am

Before.jpg[/attachment]I ended up sending my cases out to Billy at b&B Racing in Metairie (New Orleans), LA. He knew I wanted them back soon but I wasn't expecting him to finish my cases the day after receiving them. They do resto work and he is an AMCA member so I thought I'd go for it. Pricing was way more than fair and I sent a check only after inspecting the work per his instructions. He did my repairs to look good but not to a complete points standard as per our conversation. I'm very happy. He could have made the repairs more invisible had I taken the bearings and stripped the cases completely. He kept the media blast off my cases recognizing they were ready to go back together.

Last night as I was cleaning the cases, I found another hole that had JB Weld or something in it. I never saw it until I sprayed Brake Cleaner on the area. I decided to use my Miller entry level TIG for this small repair and it went pretty well considering I can't wind the amperage up like the big machines can (Right Santa?). I preheated the area with a MAPP torch and made two runs at it only after cleaning the area several times. Check it out.

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Re: Welding engine case

Postby 55panman » Sat Oct 31, 2015 10:28 am

Just a WARNING!!!!!!! Look at the ingredients label of any brake cleaner cans you use. If it has Chloro Ethylene in it you absolutely DO NOT want to use it if you are going to heat the case or WELD on the part. It turns into deadly gases when heated. Phosphene Gas. Welders have gotten deathly sick from it. There are a number of brake cleaners that don't have it. 4043 is a good all purpose filler to use in alum repair. If you're having problems with cracking after welding, 4047 seems to work better. A tip I picked up from a former air frame mechanic at Bonneville who had trouble with his Pan cases, throw the case in your propane grill or oven, if mom's not around, (I once ruined an oven) and heat treat the case at 350 degrees for 6 hours, turn off heat, leave in oven and let cool. Also another thing I got from a guy who does a lot of alum car cylinder heads, weld a little bit, stop and with a air chisel with dull bit, peen the weld. I always thought peening was only for cast iron, but I had a particular nasty repair on my Bonneville Panhead head (it kept cracking) and did all the above to good effect. Ron
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