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Fasttrack
11-29-2010, 09:43 PM
Well I finished this project back in September, but I guess better late than never.

I posted several questions here regarding the project and thought I'd post an update.

So here it is -

I needed to repair a severely damaged cast iron exhaust manifold from an old International 350 tractor. This is how it started:

http://i108.photobucket.com/albums/n22/fasttrack237/P1020167.jpg

At some point, someone else tried to repair it with a "bubble-gum" weld.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020169.jpg (http://s108.photobucket.com/user/fasttrack237/media/P1020169.jpg.html)

It was also concave by about 0.020"

http://i108.photobucket.com/albums/n22/fasttrack237/P1020172.jpg

The first thing to do was clean it. I started off by degreasing it with Simple Green, followed by wire brushing the whole thing with a SS brush.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020178.jpg

Fasttrack
11-29-2010, 09:44 PM
After cleaning, some other cracks became evident. In order to prevent the cracks from continuing to propogate, I drilled holes at the ends of the crack.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020176.jpg

http://i108.photobucket.com/albums/n22/fasttrack237/P1020177.jpg

Here someone else tried repairing with braze. Not a bad choice, but CI does have low wetability. Here you can see that the low wetability really caused some problems for the repair guy.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020175.jpg

Here it is cleaned and bolted to a simple fixture to keep everything in alignment.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020174.jpg

Fasttrack
11-29-2010, 09:44 PM
To remove the carbon deposits, I etched the casting in muriatic acid.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020181.jpg

After the acid etch, it got washed in a solution of baking soda and water to neutralize the acid and prevent rust. I then hit it with the SS brush again and then it got a serious soaking and scrubbing in acetone.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020185.jpg

http://i108.photobucket.com/albums/n22/fasttrack237/P1020186.jpg

Then it was time for the pre-heat. The oven goes to 600* F ... just about right.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020189.jpg

Fasttrack
11-29-2010, 09:45 PM
Here is the casting after being heated. I used "Peterson #2 High Heat Flux for Cast Iron". Frankly, I was not impressed. I ended up using ordinary flux for some of the minor crack repairs because it could be mixed into a paste and was just easier to deal with.

I should also add that I used a carbide bur to groove the cracks prior to brazing.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020190.jpg

I also had to blow out some broken studs, but I damaged the threads in the process. I ended up machining some bungs and brazing them in place.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020199.jpg

http://i108.photobucket.com/albums/n22/fasttrack237/P1020203.jpg

After I finished brazing, the casting was heated up to 600* F and then allowed to cool over a period of 24 hours.

Here I am machining the gasket surface flat again. Notice I'm using a solid carbide 3/4" endmill. I tried it first with a flycutter but even on the slowest speed I was dulling the cutter in no time flat. It wasn't too surprising - most castings end up with hard skin of something akin to white cast iron, it seems.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020204.jpg

Fasttrack
11-29-2010, 09:52 PM
Here it is afterwards:

http://i108.photobucket.com/albums/n22/fasttrack237/P1020210.jpg

Another shot:

http://i108.photobucket.com/albums/n22/fasttrack237/P1020211.jpg

Then I painted it with some $$$ Por-15 high heat "Black Velvet" paint.

http://i108.photobucket.com/albums/n22/fasttrack237/P1020215.jpg

Overall, it turned out pretty well. That Black Velvet paint really is good stuff - way better than the rattle can stuff that seems to turn to powder and wipe off on your hands.

Ken_Shea
11-29-2010, 10:32 PM
Fantastic job Fasttrack!

And it looks like it was a job too!

Going to do a look see on the "Por-15 high heat "Black Velvet"
May be just what is needed.

Carld
11-29-2010, 10:48 PM
Nice job and welding manifolds is always a tricky job and time consuming if done right.

Fasttrack
11-29-2010, 11:07 PM
Well I like to think I did it right, but regardless it was definitely time consuming! :)

Arcane
11-29-2010, 11:09 PM
Looks great. These repairs are very interesting to me, since I own a few old tractors. Thanks for taking the time and effort to post pics and give us a description of your process.

ADGO_Racing
11-29-2010, 11:42 PM
Great job Fasttrack! Having done a number of them myself you certainly did do it the right way. It is VERY time consuming to repair any cast iron properly.

I will say, you can get away with 400-450F for preheat, if you have enough torch to keep it hot. Or as I do, put it on a propane grill or heating pot, and keep it hot while you are working. I do repair certain "issues" with cast iron blocks for race engines. Never had a failure yet. However, with heads and blocks, I pick my battles carefully.

Glad to see someone doing quality work!:D

Highpower
11-29-2010, 11:55 PM
I needed to repair a severely damaged cast iron exhaust manifold from an old International 350 tractor. This is how it started:

http://i108.photobucket.com/albums/n22/fasttrack237/P1020167.jpg


Holy cow! :eek:

I wouldn't call that severely damaged. I call that bringing it back from the dead!

Impressive work. Kudo's. :cool:

Fasttrack
11-30-2010, 03:17 AM
Thanks for all the kind words, folks. I think if it had been mine I would've been tempted to find a junkyard replacement or make a header out of steel pipe, but it belonged to my lady-friend's father. There is a very high probability that he will be my father-in-law in the near future, so I figured before I talked to him about his daughter I better soften him up by fixing his exhaust manifold. ;)

I'll keep the temperature advice in mind. I recall reading somewhere that 600* was when a phase transition occured in cast iron and that 600* was the proper temperature for annealing but I wasn't sure what temp would be good for a pre-heat.

Black_Moons
11-30-2010, 05:43 AM
Very nice job. Whole 9 yards done to it, Real improvement!

Only thing I wonder about when flatening down mating surfaces...
Is the motor side flat or convex? :)

vpt
11-30-2010, 08:10 AM
My oven only goes to 500 so that is what I use all the time and everything so far has come out good. There was one mitsubishi 4 spider differential that didn't want to take weld for some reason but after lots of work it held and never broke in the car. I have yet to get excited about welding cast, its not my favorite job in the shop.

Very nice job on the mani! I too would have made up the jig and thrown the mani out and built a tube header and intake.

rockrat
11-30-2010, 08:40 AM
Indeed, a nice job and good writeup.

rock~

Willy
11-30-2010, 09:09 AM
Yes, excellent job Fasttrack, not only on the repair but also in the well documented and illustrated post.
I too have done a number of manifolds and heads and preparation seems to be 90% of the effort required to do an effective repair or restoration.
By the time you get to the actual brazing or welding aspect of the job it seems almost anti climatic.

I have to agree with ADGO Racing when he says that you have to be able to pick your battles wisely.
Did one a few years ago were restoration was not a viable option anymore. After assessing the work required to bring this particular piece back from the dead I found it easier and more cost efficient to start from scratch and fabricate an entirely new manifold from thick walled tubing.

Guido
11-30-2010, 10:47 AM
Just passin' through, but, what is the second 'outlet' on that manifold used for?

--G

jimmstruk
11-30-2010, 11:24 AM
Guido and all concerned, the extra outlet is actually the inlet mounting for the updraft carburetor!! JIM

Fasttrack
11-30-2010, 12:13 PM
Thanks guys. Like I said, this wasn't my own manifold so I don't know much about it. I'm not sure what that extra outlet is for - if it is the inlet for an updraft carb, I'm a little bit confused as it ties into the exhaust ports for the number 1 and number 6 cylinders. They only exhaust through that outlet/inlet. The center four cylinders exhaust through the other outlet.

I really don't know anything about anitque tractors. Like I said, I just wanted to impress a future father-in-law :o :D

Guido
11-30-2010, 01:00 PM
OK, good to go, the manifold is for a four cylinder engine, using an updraft carb. We wuz respooling back about 60 years to the Chevrolet stovebolt six, where the exhaust manifold was 'split' for dual pipes, by installing a baffle twix each end and adding a second outlet. What a mess.

Your repairs reflect thinking and carrying out a viable execution. All we remember was brazing rod, flux and heat, heat, heat.

--G

Circlip
11-30-2010, 02:33 PM
Going back to the first photo in post #5, should there actually be a split between the outer port flanges and the inner ones? Where the bright brasing line shows.

Seem to recall having a cast iron "Combined" manifold that had this feature. The two "parts" were clamped to the block face with a washer and nut clamping both.

Allows the hot and "cold" sides of the manifold to expand at different rates.

Regards Ian.

Fasttrack
11-30-2010, 05:03 PM
Ian - I'm not sure, to be honest. I thought about that, but the split looked to be rough like it had cracked, so I brazed either side but only with a thin bit of braze. I didn't figure it was neccessary, so I just did it for aesthetic reasons. I hope it doesn't cause problems further down the line. We'll just have to see :eek:

gnm109
11-30-2010, 08:59 PM
That's a terrific job. The heat you used is fine. The hotter and cleaner the part, the better the brazing job. I've brazed a couple of manifolds for small four cylinder cars and I used smilar techniques, although I used a torch for preheat since that's all I had.

Excellent explanation and pictures. Thanks! :p

Don Young
12-23-2011, 10:01 PM
Thanks guys. Like I said, this wasn't my own manifold so I don't know much about it. I'm not sure what that extra outlet is for - if it is the inlet for an updraft carb, I'm a little bit confused as it ties into the exhaust ports for the number 1 and number 6 cylinders. They only exhaust through that outlet/inlet. The center four cylinders exhaust through the other outlet.

I really don't know anything about anitque tractors. Like I said, I just wanted to impress a future father-in-law :o :D

I realize this is an old thread but I think I can clarify things a bit. This is a combined intake and exhaust manifold for a 4 cylinder engine. There are 4 individual exhaust ports and 2 intake ports. Number 1 and 2 cylinders share 1 intake port and number 3 and 4 share a second intake port.

Combined manifolds provide heat to the intake manifold in order to help vaporize the low grade fuel used in these old tractors.