Hi,
I have had some interesting sounds coming from my 1970 442 lately.
Being new to the car, I sent it to a mech to look at it and listen to it and see it he thought there was anything to it.
He has fixed several minor things and oiled and lubed it up well.
The car had a idle that I thought was a little rough and I asked to to look into it.
He/We have changed the plugs, checked timing and distrib, checked Rochester carb and ever put on a spare to see if it would make a diff, put in a new small silver valve like part (I can't remember what it is), sprayed something looking for vacuum leaks and nothing. All cylinders work great.
No smoke what so ever. Runs great in all gears.
He took off the intake manifold to replace gasket. It looked out of shape on edges. He noted that the intake has no holes or cracks on the outside, but said it looks like it has small cracks on the inside (he said he can hardly see them they are so small) I didn't see them to describe them better. The first gasket did not go on right, so he had to put on another. It has an aluminum
W30 intake on it.
Idling the same. Not bad, just not like I think it should be. I don't know what cam it has. I guess it could be a stronger cam..???

I'm saying all of this to ask, do intake manifolds go bad on a regular basis?
Keep in mind, car runs great as is, just shakes a little when stopped.
Any thoughts please?

 

Intakes only go bad if they are dropped while off or involved in a really bad wreck. Other than heat and fuel, there is nothing loading an intake that would make it crack on the bottom. The only place I could see it cracking would be around bolt holes if someone over torqued it bigtime.

What he is seeing is probably flashing from the original casting. Depending on where he's seeing it, it could be a non-issue even if it was cracked. With that W-30 intake being as valuable as it is I wouldn't be in a hurry to replace it. I definitely would want to know what cam is in the car, and I would post a video of it idling for us to help you evaluate it.

 

Not that it can't happen but I don't think the manifold is bad. Did you change the carburetor base gasket? Did you measure the vacuum if so what was it at idle? How old is the gas?

 

It's not unusual for a casting to have hairline surface cracks that to not affect anything. Unfortunatley you can't magaflux an aluminum intake to see how deep the cracks are.

 

Ok.
Got car back from mech.
Here is what I did.
Change plugs, oil, carb base gasket, manifold gasket, thermostat gasket, adjusted timeing adjusted carb and other items not related to engine.

He put timing back to neurtral, even tried another carb and the car idles the same.
He searched and checked for vacuum leaks and could not find any.
He is convinced it is the cracks in the inside of the intake manifold. Checked compression and said it was good and equal in all cylinders.

The car seems to have more power or reaction to acceleration since getting it back. The idle rpm is a little lower than it was, but not much.
The car runs so good, I'm wondering if it is supposed to be like this.
Maybe a diff cam is in it and I don't no the difference.

One last piece. For the first time I had to jump the car off today after sitting two days. I think it may be the alternator. I took it to get it measured and the battery read great but the voltage read 13.25 and the amps were under 30. I really don't know what that means, but I had it checked.
Thanks for help.
B