Is my intake manifold too warped?

[TheGeneral]

I am trying to fix an exhaust manifold leak and I have never done this before. I got so caught up in the cracks and crevices to clean for painting that I didn't realize how crooked the intake is. The ports seemed to all be touching the tarp though?...

Is this a normal amount of bend, or a clear warp that means I need to replace it?? I was incredibly unimpressed with the new exhaust manifold I bought already (I know now I should have bought both). I am already well in over my head but I am plowing forward, I just do not have the resilience some people have where they do the manifolds one, two, three times !!!! before getting the leak fixed.

Advice from ye wise sages??

[Gary Lewis]

As said in the other thread, put a straightedge on it to see how much warp there is. You'll be checking where it bolts to the engine, the faces of the runners.

[TheGeneral]

As said in the other thread, put a straightedge on it to see how much warp there is. You'll be checking where it bolts to the engine, the faces of the runners.

ok thank you,

sorry about the double post, I am unsure if stuff gets lost in a long thread or what...

[Rembrant]

I got so caught up in the cracks and crevices to clean for painting that I didn't realize how crooked the intake is. The ports seemed to all be touching the tarp though?...

Is this a normal amount of bend, or a clear warp that means I need to replace it??

Yes, it is a normal amount of bend. It was cast that way from Ford, although I don't know why. Maybe one of the 300 experts on here can enlighten us as to why. Yours is upside down in the picture, but here is a picture of the intake on my 300, and you can clearly see that the front intake ports go level/straight into the cylinder head, but the rear end of the "log" curves upwards, and the ports are curved downwards. That's not warped, that was made that way...but I have no idea why.

You've probably already found this, but on the two 300 intakes that I had to work with, both were cracked in two places. See the arrows below...both front corners of the intake "box" that serves as the carburetor heater. Each corner was cracked at least an inch long vertically, creating pretty nasty exhaust leaks. I welded mine up, which was a slow and tedious process (welding cast iron) but I did get them sealed up in the end.

I only have limited experience with the 300, but I would say that even if that intake isn't 100% flat where it bolts to the cylinder head, I wouldn't worry too much about it right away. The bolts will suck it in tight, at least a little bit. And by a little bit, I'm talking maybe 0.020", not an 1/8". If there were two intake runners side by side that were off significantly I would be concerned, but if the intake is off by a few thousands from end to end, I wouldn't be worried too much.

Use all new gaskets and all new bolts (make sure you have the original thick washers), and tighten it all in evenly and slowly.

 

[FuzzFace2]

I got so caught up in the cracks and crevices to clean for painting that I didn't realize how crooked the intake is. The ports seemed to all be touching the tarp though?...

Is this a normal amount of bend, or a clear warp that means I need to replace it??

Yes, it is a normal amount of bend. It was cast that way from Ford, although I don't know why. Maybe one of the 300 experts on here can enlighten us as to why. Yours is upside down in the picture, but here is a picture of the intake on my 300, and you can clearly see that the front intake ports go level/straight into the cylinder head, but the rear end of the "log" curves upwards, and the ports are curved downwards. That's not warped, that was made that way...but I have no idea why.

You've probably already found this, but on the two 300 intakes that I had to work with, both were cracked in two places. See the arrows below...both front corners of the intake "box" that serves as the carburetor heater. Each corner was cracked at least an inch long vertically, creating pretty nasty exhaust leaks. I welded mine up, which was a slow and tedious process (welding cast iron) but I did get them sealed up in the end.

I only have limited experience with the 300, but I would say that even if that intake isn't 100% flat where it bolts to the cylinder head, I wouldn't worry too much about it right away. The bolts will suck it in tight, at least a little bit. And by a little bit, I'm talking maybe 0.020", not an 1/8". If there were two intake runners side by side that were off significantly I would be concerned, but if the intake is off by a few thousands from end to end, I wouldn't be worried too much.

Use all new gaskets and all new bolts (make sure you have the original thick washers), and tighten it all in evenly and slowly.

I also pulled this from your long post:

It is one thing to check if the sealing edge is flat to seal but another that the ports on the intake line up to the ports on the head.

If you get the 2 end ports to line up the center ports may be to high.

If you get the center ports to line up the 2 end ports may be to low.

I would take that straight edge and check the head at the top or bottom of the ports or both to see if they are straight across then do the same on the intake.

Think before I even did that I would take the gasket and lay it across the intake and see if it lines up as it may show the ports to high or low too.

Good luck.

Dave ----

Cory, I had a AMC 258 six that also had a large crack in that area.

I replaced the donut for the head pipe and still had a leak.

Digging in deeper is when I found the exh manifold was bad.

I was lucky that the exh manifolds were the same on the 258 wither it used a v1 or the rare v2 intake, that mine had, and the parts car one worked.

In my case the leak was so bad it caused a vacuum leak and once replaced it ran like a new motor.

Dave ----

[Rembrant]

In my case the leak was so bad it caused a vacuum leak and once replaced it ran like a new motor.

Dave ----

On the 300 intake it is not as serious as the cracks are only on the exhaust side, not the intake side. It makes for a bad exhaust leak noise, but it doesn't harm anything else.

Of the two 300 intakes I had, both were cracked in both places. I did see the same cracks on junkyard trucks as well. A symptom of our climate up here? Starting the engine up in the cold weather? I know the intake casting is really thin in those corners, which doesn't help the situation.