cam weld issues

[Vash]

hey guys i need some help real quick we started my cam weld yesterday and we are having some problems.

the welds are penetratng good into the camshaft and the nut on the front exhaust cam but the welds on the sprocket side are porous. my instructor wants to know what you guys do to prevent this porosity and if we should remove the porous welds and weld again? he thinks it is contamination boiling out but i would like yopur guys opinion on this.

he is using a lincoln 350 with 95% argon and 5% oxygen and using .035" ESAB ER-705-6 wire

any help would be great!!

if you need any more info just ask and i will see what i can do.

 

[St Louis SHO]

Make sure you clean the cams/sprockets with brake parts cleaner until the oil quits bleeding out. After that if it does it, turn up the heat...

 

[Bob Gervais]

And use 75/25 gas.

 

[Vash]

i will post a pic of what its doing in a couple hours. see what you guys think.... it seems like even brake clean is not working very good.

 

[LJRuddy]

And use 75/25 gas.

Im with stupid. Thats waaay too much argon. Would be a decent combo if you were welding aluminum though. :wave:

 

[Vash]

ok here is a couple shot of a weld from today. as you can see the weld on teh nut looks good but the one between the nut and the sprocket are not so great. could this be caused by an incorect gas mixture?





thanks for all your help so far!

 

[Mr Anonymous]

Bob and James are spot on. You'll always get a little bit of oil contamination causing a couple of spots, but the ArO2 combined with a wire that may not be best when you consider that the sprockets are a different metal than the shafts and nut are probably contributing as well.

 

[Bob Gervais]

Im with stupid. Thats waaay too much argon. Would be a decent combo if you were welding aluminum though. :wave:

Actually, the argon content isn't so bad, it's the oxygen that's going to make the weld brittle and porous.

Oxygen isn't recommended for use in any aluminum welding, because it oxidizes the weld.

That 95/5 would be good for stainless though.



Now, onto the weld appearance. Since it's already done, and it seems that at least some of that bead is good, I'd leave well enough alone. Keep in mind, you're not trying to hold the sprocket radially (unless it's already slipped), you're trying to hold it axially, which requires much less weld strength.

IMO, going in there with a die grinder to get that bad weld out is going to do more harm than good.

Also, Chris, the wire he stated as ER705-6 is most likely a typo, and is actually ER70S-6 wire, regular ol' steel welding wire.

I definitely agree though, the different hardnesses of the components makes it a little difficult to get a good setting until you've done a few. I've never done any actual "cam welds", aside from messing around with junk cams.

To the OP, switch gases to 75/25 Argon/Carbon Dioxide, turn the heat up some, and you should be fine. Oh, and make sure the polarity is correct on the welder.

 

[St Louis SHO]

I'm with Dr Bab, and I've done lots o' welding.

 

[AREA 91]

Thank's for all the info on the cam welding guy's!
Can some of you post some more pic's of cams that have been welded.
I have a 97 that's gonna need to be done, and would like to do it myself.
:thankyou:

 

[Liquid_force]

The guy that did mine just used some generic wire and CO2.
He told me before I agreed to any work that they wouldn't be pretty, but they WOULD be effective.
Used a little brake cleaner and just gave each cam a quick wipe. Put down some damp towels and taped off the area right near the cam taking care to protect the lobe nearest the welds.
There was more porosity than I would have liked to see, but per the welder's suggestion I took a small punch and "popped" any obvious bubbles and then tapped any rough edges which smoothed them out pretty well.
I thought they came out pretty good, especially for $65.

I've driven it over 3k since then and it's running really well.

 

[escortlvr]

Thank's for all the info on the cam welding guy's!
Can some of you post some more pic's of cams that have been welded.
I have a 97 that's gonna need to be done, and would like to do it myself.
:thankyou:

Stainless wire 308/308L Tig weld is what we did to mine..

 

[Bob Gervais]

Thank's for all the info on the cam welding guy's!
Can some of you post some more pic's of cams that have been welded.
I have a 97 that's gonna need to be done, and would like to do it myself.
:thankyou:

Brian, I don't have any pics, but I think there's some on V8sho.com, if you search around a bit.

 

[Vash]

ok welding is done. they ended up welding it solid all teh way around the cam... i guess they wont break...










it just needs to be cleaned out and put back together now.

 

[tool88]

that much heat could actually make the cam weak, but it does look solid.

 

[Vash]

anyone else have an opinion on this? the car is going back together. not sure how close it is to starting yet but should be very soon. i am hoping that they will be fine...

 

[LJRuddy]

Well thats one way to do it I suppose...

 

[Bob Gervais]

Turn the engine over by hand with a socket on the crank pulley. Make sure none of the welds are interfering with anything else. Run one of those telescoping magnets through the head, blow everything out well, maybe splash some oil on the cam lobes, and put her back together.

 

[Bob Gervais]

Well thats one way to do it I suppose...

And this is helpful, how?

 

[Vash]

they ran about 10 quarts of oil through it i gave them 2 oil filters. the car is almost back together should be running today (Monday) i hope. they didn't check for clearance bot i dont know what the welds would hit anyway? not anything really that close... anyway if they get it running i will let you guys know how it runs!

on a side note you think i should get a magnetic drain plug?