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TIG Welding Ali - A Dry Sump Pan

5K views 13 replies 10 participants last post by  Brian_S 
#1 ·
I decided to get the TIG out and finally get on with the dry sump pan for my 2.5ltr V6. Lee had some spare fittings from his Pace dry sump which are pretty cool, they have a gauze filter inside a "pickup" tube which is then screwed through the sump pan. It's probably easier to just look at the photos of them!

I started off by milling down a Vectra sump. I think I milled it down to about 35mm, this clears everything that is under the engine. I have the subframe cutting across the front of the engine, right under the sump so I need to keep the sump as low as possible at the front of the engine.

With what was left of the sump pan bolted to the block I chucked the block on a welding table and started rough cutting some 2mm aluminium to make the bottom of the dry sump pan. Luckily the windage tray bolts directly to the main cap girdle, so the sump pan is litterally just an oil catcher! I started off by cleaning all the aluminium. I cleaned the sump with thinners to get as much oil off the pan as I could, and then I gave everything a good scrub with a stainless wire brush. It is vital to get rid of all aluminium rust before trying to TIG anything.







Once I had the rough size done, I did a couple of tack welds to hold the plate in plate, and then profiled the plate with a die grinder to the same shape as the sump pan. It was then the moment of truth, to start welding!!





I started off with an already balled white tungsten (about 2.4mm dia.) and I was using a 2mm (I think! I must check that) filler rod. I started at 70amps, this turned out to be a bit less than I needed, so I moved to 80amps. This was fine, but unfortunately I don't have an adjustment (pedal or finger control) for the current, so I could only go so far before the heat soak meant that the current was far too high. Then I would have to stop, wait a 30 seconds and start again. I think I'll definitely get a foot pedal for Matt's TIG. It would be very useful for ali. Initially, the heat arc was hard to predict and seemed a bit scattered. After a while I decided to snap the tungsten to weld with a new end, this helped a lot and when it had balled this new end was very concertrated and worked really well. I also moved the tungsten so that is was protruding about 2mm out the end of the shroud. Gas was Argoshield.







In the end, the pan came out okay. There are a few places where I could have done better, but then this is the first time I've TIG welded ali (at least without trying to use a stainless filler rod by accident!!) and everything looks tidy enough and looks like it won't leak oil everywhere. Looking forward to bolting the engine back in now and getting on with the exhaust manifolds! :) :beer:
 
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#2 ·
Ally is particularly difficult to weld - nice effort though - very challenging "first" project I must admit.

Looks great too...

Just a remark: if the sump is cast aluminum, what did you match it with? regular ("pure") aluminum? And with what rods? %Si => could you check that for me please?
I've done repairs on cast Aluminum, with upto 8 % Si filler rods, however I'm not sure what should be used when mating cast with regular aluminum, but I'm guessing you'd need a high % Si too....
 
#5 ·
Cheers guys, I'm pleased with it and at least now it's done. I've been meaning to do it for ages!



Yes, reg "pure" aluminium; nothing special. The cast aluminium used in the vectra sump is pretty good, I expect had I tried to weld something like the old manta sumps it could have been a different story. I will get the Si content information for you when I'm next up the garage for the rods.

I should note that I also moved down to 60A when I was welding the two 2mm plates together. I forgot the rule of thumb about amps per thou. so just kept fiddling with the current until it seemed right. Even so, a foot control for the current would have been extremely beneficial. I could have done much longer, and more consistent welds.
 
#10 ·
Well the pan fit nicely on the engine, and was well below the line of the flywheel/bellhousing but it didn't go back far enough to clear the subframe. Boooo! So now I have to notch the subframe. I didn't really want to, but needs must and all that. The only other option was to make a front extension for the sump pan to come out over the front of the rack. It's partly my fault for sitting the engine so far back. I don't want to take the front scavenge back any further because else under braking the crank is going to get swamped in oil.





Oh, these were the rods I used (because they were up the garage! lmao ), they were 2.4mm too. No silicon, just 5% Magnesium.



I will try altering the frequency Gav, cheers for the tip. Once I had the set setup so that I could weld, I didn't really want to change or alter much in case I 'ked it up. PLENTY more to learn! lmao
 
#11 ·
For welding cast you want 5% silicone rods. 4043 from memory.

Ally welding without a pedal is a real pain in the arse due the big range of currents required at different stages of the weld. Sounds like you found this out though.

The other thing is that sump is not nearly clean enough to weld. I weld alot of sumps and the first thing i do is have them steam cleaned. Then you need to clean the weld affected area with a wire brush wheel on a drill until you have shinney fresh ally. Try to weld within 10-15 minutes of cleaning or the ally will begin to oxidise again.
 
#12 ·
Do you mean not clean enough for a perfect looking weld (which im sure Brian wont worry about too much on a first attempt) or do you mean that it will actually have problems like leaking as a result?
 
#13 ·
Not clean enough as in you have more of a chance of it leaking. The dirty ally will cause porosity in your welds that the oil can leak through.

The finished weld should be clean and free of any colour other than ally. If you have any black floating round in your weld pool the ally was not clean enough or your gas flow was too low.

After i weld an ally sump I always place white kitchen roll on my work bench, place the sump on it and, fill with a red penetrant dye and then leave to stand for half an hour. Any tiny leaks are easily spotted. Nothing worse than fitting an engine back in only to find the sump leaks and its got to come out/apart again.
 
#14 ·
Well, I'll soon test for leaking by filling the pan with parafin or something and see what happens. But for the moment the welds do not look porous (enough to leak), but the pan could definitely have been cleaner! lol I will check it when the engine is back out of the car after I've done the exhaust manifolds.

I will have a look around for some dye, but tbh it feels easier to drop some real liquid inside it and see if anything leaks?

Cheers for the tips though, I'm on the 89 degree learning curve at the moment! lmao
 
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