Separating 2.25 intake/exhaust manifolds

[bsa_m21]

I have a 1969 2.25L that I am rebuilding. I am trying to separate the intake/exhaust manifolds with no success. The 4 studs holding the intake on, are completely corroded in place. I have tried gouging out as much corrosion as I can with a pick, but that only gets down about 1/2", heating the aluminum & bashing it with a brass hammer, soaking the studs/holds with oil overnight. But nothing has loosened it so far.

I'd appreciate any and all suggestions.

Thanks.

M.

[John]

I've had that battle. When all is clean there is a good clearance between the stud diameter and the holes through the intake manfold. I was able to take a piece of thin wall tube and cut some notches at one end to simulate saw teeth. I then chucked the tube in a drill and used this to clean out the corrosion. It worked quite well.

Good luck,

[bsa_m21]

Great idea! I had thought of a small hole saw, but it wouldn’t have been long enough. I’ll give this idea a try tonight.

Many thanks.

[StuartC]

If you run into an issue I have two intake manifolds you can have.
1 is tapped for a vacuum line the other is not.
I had the same issue with separation of the two....persistence and patience.
I sandblasted mine, used hi-heat silver on the aluminum, and hi-heat "cast" colour on the exhaust.

[bsa_m21]

If you run into an issue I have two intake manifolds you can have.
1 is tapped for a vacuum line the other is not.
I had the same issue with separation of the two....persistence and patience.
I sandblasted mine, used hi-heat silver on the aluminum, and hi-heat "cast" colour on the exhaust.

Hi Stuart. I might take you up on the offer.

I’ve been trying the trick John suggested, with mixed results so far. The back two stud holes (closest to motor) I was able to drill down and think I’ve cleared the crud. But the front two are giving me grief. Prior to trying the tube cutter method, I had tried using a long 1/16” drill bit to loosen the crud, but it broke off deep in the hole. The tube cutter steel just dulls when it hits the broken drill bit. Damn…. Going to try more heat and “5lb persuasion” tonight.

[StuartC]

Hi Martin
Yes, they can be a challenge.
Let me know what you need. I will send you a PM re my contact info.
Stuart