Refurbish 67 273 Exhaust Manifolds

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DesertRat

Leading edge boomer
Joined
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Moses Lake, Washington
My winter car improvements include R & R the cast iron exhaust manifolds which were treated once and it was an epic fail. I will use VHT silver with silica good for 2000 degrees. We'll see.
Ex1.JPG
They detract from my engine bay and must be dealt with.
ex2.JPG
They are headed for hot power wash followed by beadblasting and lacquer thinner wipedown.
ex3.JPG
Spoiler alert; The project is completed and The manifolds are heat cured in. I will post the photos sequentially as done on the project. Cheers--------------
 
I shot this series with two cameras and had to gather my other camera cable to download the progress photos. Photo one shows the manifolds out of hot wash ready for bead blast.
Prep1.JPG
The second photo shows the manifolds out of bead blast and air cleaned ready to hang for prep.
Prep2.JPG
The third photo shows the parts hung up on my "pop-up" paint booth at my employer's shop. It is because of them that I have access to the hot wash and bead blaster as well as setup space.
Prep3.JPG
I am now ready to wash them down with lacquer thinner.
 
Now that they are hanging I have to clean them for paint without touching them. I cannot wipe them as it will leave fiber and residue. My method is to use my detail gun and wash everything down with Laqeur thinner until it run off the items, usually taking a black color off the items.
paint1.JPG
This is the paint I used, I choose not to use any primer as I will explain later. I did follow the directions as much as they fit into my own program.
PaintA.JPG
I sprayed a couple tack coats waiting about 20 minutes between coats.
paint2.JPG
I sprayed out one can of the paint but I bought two to be sure. I think the third coat was heavy-wait 10 minutes and finish out the can.
paint3.JPG
The parts are all now painted, it was new years eve day and I let them hang until Thursday morning when I gathered them and installed them on the car.
paint4.JPG
To this point things are looking pretty good.
 
This is the mockup on the bench. I used all SS allen head fasteners and polished them. My intake and valve covers are all SS allen head fasteners as well, I like the look.
exas1.JPG
This is the right side before photo.
exas2A.JPG
This is the right side after photo.
exas2.JPG
This is the left side after photo and I don't have to tell any A-body owners how difficult this was to R & R without removing any other parts. Band-Aids everywhere now.
exas3.JPG
This is the finished project photo. I heat cured them on the car and the paint kept it's as sprayed lustre and finish. No flaking or peeling, I think it is solidly bonded to the cast iron.
exas4.JPG
What I know: All liquid applied coatings (paint) require a "gassing-off" period. One must know when to move to the next step safely. This is why I did not use any primer under the color.
What I learned: Cast iron is very porous and absorbs all the wash, blast, solvent and paint much more than tube or plate steel. This increases the gas-off time exponentially. The on-car cure instructions are possibly suitable for plate or tube but not suitable for cast iron. The instructions call for an initial run in of 20 minutes-do this at your very great risk. I was watching mine closely and after 6 minutes I saw some bubbling and shut the car down. I let it cool to hand warm and started the car again and watching it closely let it run for about 18 minutes up to 140 on the water temperature gauge. I called it for the night and let it sit overnight. The next morning I inspected the manifolds and they looked really good, I started the car and let it run for 35 minutes and got the water temperature up to 190 degrees. Then I shut it down and called it good. This project is complete and I have 2 or 3 more little things to do to the car before the spring roll out. Cheers and thanks for reading----DR----
 
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When i did my headers between each coat i used a heat gun and warmed them from the inside and let them cool. 4,000 miles this year and still look great.
 
I used that same paint on the manifolds for my wife's Dakota with a 4.7 motor. I just ran mine thru the blast cabinet, and pretty much half assed did it compared to how careful and meticulous you were with yours. After 3000 miles of daily driver duty, they still look great! No flaking or bubbling at all.
 
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