Welding the oil pan?

[mramay]

Finally ready to weld some plate in the cross member clearance hole cut in the GTO pan but I have a couple of questions.

Is there a chance the oil pan will warp? I have some 0.19" thick plate cut to fit the hole, which is about 4" long and the width of the pan, and a plate about 2.5" tall to weld in vertically fill in the sump. I could bolt the pan onto a double thickness of 3/4" wood so it can't move, but that might result in heat induced stresses that I don't understand.

The other question is do we need to weld inside and outside on the filler plates? Welding only the outside will probably be strong enough, but that likely leaves a groove/crack on the inside where the plates mate up to the pan.

Thanks,
Mike

[68 TT]

Bolt the pan to the block without the gaskets and torque it down.

Pre-heat the pan and infill pieces with an oxy-acetylene torch. Coat the parts with soot from an acetylene only flame then turn on the oxygen and heat the parts until the soot goes away. It is now at the right temperature to weld properly.

A good weld on material that thin will have penetration that fills the void all the way onto the back side so no crack is visible from the inside. You will not have to weld it from the inside too.

Tack it all together where you want it then weld an inch on one corner then move to the opposite corner and weld another inch. Skip around the pan welding small bits at a time then moving on to an opposite area for the next section of weld. This combined with the pan being bolted down solidly will prevent it from twisting the pan and making the pan rail warp.

['JustDreamin']

Also, make sure you get it ABSOLUTELY clean. The cast pans can actually soak up some of the oil and make it good fun to get a decent weld. I've seen people recommend getting it really clean with degreaser or the like and then running it through the dishwasher. I haven't tried that yet, but I've seen it recommended.

Preheating with the torch should burn off most of the residual crap in the metal, however.

'JustDreamin'

[mramay]

It is clean and I can make it a bit cleaner. I've already sandblasted it inside and out and will hit the edges that will be welded with some brake cleaner, then sandblast them again.

I have used the "weld a little on this side then on that side then over there" process before (de-seaming a sheet metal roof on a Mini Cooper), but didn't know if this small, thick pan would need that. Sounds like it does.

Thanks. I'll clean it and bolt it down.
Mike

[Old Geezer]

Clean the weld areas w/ MEK...Clean the weld rod w/ MEK.

[mramay]

Originally Posted by Old Geezer

Clean the weld areas w/ MEK...Clean the weld rod w/ MEK.

I have chlorinated and non-chlorinated brake cleaner but no MEK. Should I buy a little of it or wait for the welder to show up and see if he has some MEK, then clean the edges and sandblast them.

Thanks,
Mike

[Grr]

ive welded a handful of these pans, never bolt them to anything, just blast, clean with brake cleaner then a torch, and weld. Never had any problems with them warping or leaking. I put my first one on a belt sander and it was still perfectly flat. Just weld it the flange is close to 1/2" thick it isnt going anywhere. Bolting it to the motor will just ruin your day making it way too hard for what it is