The Silver Buick's 1969 Firebird OHC six project.

[Deaf Bob]

Nickel rod?
Or do you only weld MIG?
Seems stick welding is a lost art..
We do all out cage/side irons with stick..
MIG only the body..

[TheSilverBuick]

Just run of the mill MIG.

[Deaf Bob]

Just run of the mill MIG.

Many guys think you need a certain position to weld..
You probably could have upped the amps a bit and maybe held the nozzle a slight angle off 90* , shooting into the metal..
Get some pentrention, and flattening your bead a bit,
Look at the bottom of your bead.. It will show if you got pentrention
Tower or light post welds generally do not have bead humps.. Side to side is flat

[Deaf Bob]

Please don't think I'm doubting your ability..
Merely trying to help..
Squirrel's right.. One continious bead would be better.
When the tower welders plugged holes that I punched on the wrong spot, they backed the hole with copper, did one bead starting on the hole and going in circles untill it was a slight hump.. Did not take much grinding to flatten..

[TheSilverBuick]

My "RTV" method of welding for the injector bungs. The trouble I had was the same problem I had the welding the rest of it, which was blowing through the thin metal. So I what I eventually did was dial the heat and feed way down and lay a bead on the thin metal, then went back over it with more power, effectively welding the weld to the bung, then stacked it, and then turned the heat up some more and stacked it again.... However I think I learned what setting would work well the next time I weld this thin metal.

I still have to do some finishing grinding/polishing on the inside of the ports, but then will give it a coat of fuel resistant sealant and then paint will make all the flaws go away



Finishing work still required.

[squirrel]

With thin metal, you kind of have to stitch weld....

[Huskinhano]

Hey, as long as it holds you should be fine. I have a 140 amp Lincoln flux welder in my work truck. I would have done it in 1 shot too. Not from an expert point of view which I'm not. Just that it isn't sheet metal and isn't going to warp too easily. I think it was in HRM where they covered a repair to an early numbers matching vette block that the outer starter by hole cracked because the work by was used. What the shop did was to grind out the crack for the bead. The cut threads on a piece of carbon rod and threaded that into the bolt hole getting fixed to prefect the threads. They heated the spot up with a torch and used a high nickel rod with an old arc welder.

One problem I've had and I think most people do is not to have the amps high enough. I crank em up and have had good luck with nice looking welds with good penetration. I just stick with small stuffiness making brackets.

I have a 04 Trailblazer with a cracked exhaust manifold I'm going to give a shot at fixing with my mig.

Congratulations on the wedding. My son just got hitched a week ago last Friday.

[TheSilverBuick]

Thanks!

I bet the trailblazer manifold is a better grade of cast iron (steel?) and welds nicer than old cast iron. There is certainly a correct and proper way to weld cast iron, especially when required to have real structural integrity. My case, I just need it to hold no more than 40 psi, which would be an extreme case of running 20psi of boost and a 2:1 pressure ratio in the exhaust. Odds are it'd be far less than that.

Googling around, it seemed the big problem with generic MIG'ing cast iron is the surrounding cast iron from the weld cracks from the MIG steel cooling and contracting faster than the surrounding cast iron. So the weld doesn't crack, the adjacent cast iron does. To counter act this, heating the cast iron object up to 400-500ºF with a slow cool down is most advisable as well as peening the weld to relieve stresses, which I did do. I also beveled the welding surface and wire brushed the surface right before welding to theoretically break up any carbon coating that formed during heating. The alternative method is the cold method, which is to put as little heat into the manifold as possible. Weld smaller lengths, in sections, etc. but that method seemed to be even less advisable.

Using the oven to slow the cooling seemed to work in this case. I don't have piles of sand around, but I do have piles of fireplace ash in a 55 gallon drum and I contemplated pulling out 2+ five gallon buckets of ash from it and just dropping the manifold into the remaining ash pile and pouring the ten gallons of ash on top of it for insulation, but the drum is outside and it was intermittently raining, so figured it wouldn't insulate as well with cold water raining down.

[Huskinhano]

Good point about the mig weld contracting faster. Since the manifold is already cracked, I have nothing to loose. The last time I had my state inspection I failed for that but the shop doing the inspection welded it up. I can get a new "improved" one from Rockauto pretty cheap.

[Scott Liggett]

Your welds are better looking than the ones I have done. It is definitely one thing that requires learning some technique and then a lot of practice.

[TheSilverBuick]

Like Squirrel had been saying since the day I bought the welder five or so years ago, "practice, practice, practice, then practice some more.". For my low skill level, I really need to practice every time before I start on the project, but I don't, and it shows.... I feel its typically about 75% through the work that I figure out either the speed I move across the metal, or the welder settings that I needed to know before I started. I get a little quicker every time, but the thin stuff is by far the trickiest and until last Sunday, I was way off on what settings I needed to get it to weld nicely (flat weld). Now I know for the next intake! I bought three sets worth of steel injector bungs figuring this intake would be my learning curve.

[Deaf Bob]

Make wind chimes, yard art, teacup racks and silly stuff gals seem to like for practice..
Have you considered brazing? Controlling the heat on the thin stuff will be problemishy..

[DanStokes]

A great deal of what I do is body metal. Just takes practice and the MIG is the easiest thing I've ever used for it (I used to do all my stuff with oxy/acetylene either welding or brazing). Melt some wire!

BTW - when welding different thicknesses together I start with the welder set somewhere between the recommendation for the thicknesses involved and sometimes I have to tweak it as I go. I strike the arc on the thick piece first and sort of pull down to the thin stuff making a sort of "C" with the torch. If you start to see a blow-thru flip back to the thick stuff. Sometimes you'll have to stop for a second and let the puddle cool a bit then start back on the thicker metal. And as always, clean helps greatly (no issue on this project).

Actually, it looks pretty good.

Dan

[TheSilverBuick]

Someone posted on the OHC a link to the 1967 Pontiac service manual, which is considered the best manual for these OHC engines. One of the first things that stood out to me is the valve spring pressure were higher in 1967. It has been said Pontiac lowered the valve spring pressure on these engines to limit the rpm they'd turn to limit warranty issues.

The measured heights are different, but if you do the math the '67 springs increase pressure by a lot more over a shorter distance. Even the 1bbl head, where the height differences are almost the same the '67 has 25lbs more open when around the same on the seat.

[langleylad]

The car made it to Las Vegas and back without a hiccup. Around 550 miles round trip. I haven't filled it up since I got home, but it got a bit over 25mpg driving down there, but that is only a one tank/leg average.

The car got a part in our wedding. The wife insisted!


I was driven up to the aisle.


She was brought in with only ONE horsepower =P




Afterwards, even the car appeared to have a hangover as my brother who drove us back to the hotel left the key in the accessory position and killed the battery, so I needed to get a jump start.


Funny enough, someone left a post-it note on the driver's window saying "Congratulations" and two times going out to the car I found people standing next to it looking in, including a pair of ladies that appeared to be in their 70's! =D

I haven't been keeping up to date , congrats to the both of you .