PDA

View Full Version : Cutting and welding cast valve covers?



Cebby
12-05-2006, 08:49 AM
I have a slight clearance issue that I think can be alleviated by notching and filling one of my cam covers on my UZ motor project. I don't think I can take too much off, but it appears that a little might be all that is needed.

These are cast alum - any problem with doing this? Is there a specific alloy that lends itself to forming and welding onto this cover?

Pics to follow...

MXtras
12-05-2006, 06:39 PM
The trick to welding cast is to get in, and get out as soon as you can. Normally with AL I will let the arc melt the bed pretty well before I dip but with cast I have found that the extra soak heat draws what I assume is silcone as well as other contaminates out of the casting and makes for a difficult time welding. Just heat long enough to get the surface to wet then dip and move.

I have had success using 4043 filler and the rest of the settings are comparable to settings used for comparable thickness plate - maybe just a bit more shield volume and a bit more cleaning balance. The cast seems to take a little more heat to get started and run a weld. Clean the hell out of the casting to remove any oil, of course.

As far as compatable materials - I have mainly done casting repairs and some gussetting. I have never yet welded anything to cast other than 6061 or 6063, so I can't tell you if 5053 would be any different - sorry. 5053 would be more formable than 6061 for your patch piece. Not sure on the filler for 5053, either - I use 4043 for my limited 5053 experience.

Scott

Cebby
12-05-2006, 07:30 PM
Great info Scott! Thanks!!

I'm hoping any forming I need to do is limited since I'm not equipped to do much in this department. I'm hoping the patch is mostly flat, just shaped to do the job. I was thinking 1/8" for the patch - I think the cover is roughly 1/8-3/16.

Based on what you said above, it probably makes sense to keep the patch on the thinner side (would be able to limit the possibility of too much heat somewhat hopefully)

MXtras
12-05-2006, 10:27 PM
Test on the piece you remove from the VC. Some cast stuff welds really nicely, other stuff is a bit more finicky.

Also - make sure it's not Magnesium. (I don't even know if it could be for what you are working on, but just thought I would mention it).

Scott

Driven2xs
12-06-2006, 09:08 AM
2 other ways to attack this.

Double gasket

or

Make an aluminum spacer, with a gasket on each side.

Cebby
12-06-2006, 09:40 AM
2 other ways to attack this.

Double gasket

or

Make an aluminum spacer, with a gasket on each side.

Huh? I want to make the cover smaller/lower profile to clear the heater core hump in the firewall - wouldn't these ideas make it bigger - or am I misunderstanding.

I've only had one cup of :coffee: this morning, so I'm not 100% awake yet... :biggrinan

BoostAddiction
12-06-2006, 07:54 PM
The trick to welding cast is to get in, and get out as soon as you can. Normally with AL I will let the arc melt the bed pretty well before I dip but with cast I have found that the extra soak heat draws what I assume is silcone as well as other contaminates out of the casting and makes for a difficult time welding. Just heat long enough to get the surface to wet then dip and move.

I have had success using 4043 filler and the rest of the settings are comparable to settings used for comparable thickness plate - maybe just a bit more shield volume and a bit more cleaning balance. The cast seems to take a little more heat to get started and run a weld. Clean the hell out of the casting to remove any oil, of course.

As far as compatable materials - I have mainly done casting repairs and some gussetting. I have never yet welded anything to cast other than 6061 or 6063, so I can't tell you if 5053 would be any different - sorry. 5053 would be more formable than 6061 for your patch piece. Not sure on the filler for 5053, either - I use 4043 for my limited 5053 experience.

Scott


Ditto on the advice to clean the casting completely first. I once ruined an aluminum casting I was welding as I chased prorosity everywhere, blaming poor metallurgy. After I put down the torch it hit me- there was still oil in the crack I was "repairing" .

What a dolt :Yikes_ani - but I won't be repeating that mistake next time (I look forward to finding new mistakes every day).

-Will

Driven2xs
12-07-2006, 04:47 PM
Sorry Ceb, I read your post wrong. I thought you NEEDED valve train clearance. I'm so used to everyone needing room for roller rockers, stud girdles, etc. We always clearance the firewall and go bigger on the valve covers!!! Sorry about that!