so, I got bored amist waiting for parts to complete my build. I decided to remove the bottom panel off my 6.1 intake manifold to see how the runners look. To my surprise there was tons of aluminum welding flash slag. Since the manifold is assembled in 2 seperate pieces then welded there is the expected overhang on the weld seams, but the far rear runner had alot of burrs hanging off (probably 4mm-6mm in size) there as also some on one of the inner runners. I used a stone wheel and took the overhang down some and then removed the burrs. Might be something folks might want to look at when yuo have the manifold off next time.

I agree, the 6.1 intake is notorious for being very rough inside. I pulled mine and paid for a full porting job. It is the perfect time to have the throttle body opening enlarged so you can benefit from a larger throttle body as well.

Was your's oily? Even with a catch can mine had quite a bit of oil in it.
http://i92.photobucket.com/albums/l9/rsanborn/valvecovers013.jpg

Would you need to refine the tune after doing a "cleaning" job on the manifold?

Would you need to refine the tune after doing a "cleaning" job on the manifold?

No. If you port the TB opening and go with a larger TB you would though.

Thanks! I may have to do this one weekend.

There was a pool of oil in mine when I removed it. I had 5k miles on it before the catch can and another 3k with a catch can in place when I pulled it off. The throttle body opening measured 83MM. I had it opened to 87 mm. To go out to 90mm you loose the "O" ring groove. You can gain from having it tuned after any mods, I waited until I had done all the easy bolt ons, HP went from 393 rwhp to 420.

If you "clean" up the welding inside the manifold you don't need to worry about a tune. If you port it, it would be a good idea to have it tuned. The oil thing is a rediculous issue that these engine seem to have. I am thinking about venting my crankcase to atmosphere and pluginf the port on the manifol to keep oil from pooling in the back of my manifold. The cathc can cut down on some of the oil collecting, but there is still alot and it showed on the combustion chamber. I could do without that gunk in my motor this go-round!

Most modern engines will pass some oil into the intake because of the closed crankcase ventilation, this condition is not unique to the Hemi.

True, it is impossible to collect all oil particles out of the vented air out of the crankcase. These engine (well manifolds) do the worst job of getting any oil out of the vented air of any of the "modern" engines I have worked on. If you look at the posted pic of the guy's intake manifold you can see the collection baffles that are designed to collect oil particles and drain them back into the crankcase. These are not addiquate enough for the amount of particles that are produced or the ability to drain back into the case is too poor. The guys pic looks really tame, I used to get a rag and soak up the oil out of my manifold.