ok so...i have ported and polished before....so this is by far not new to me...

i have ported 416 castings before...no problem

heres the problem....

416 castings.....

i was Gasket matching the intake ports, on the bottom right hand side of the port , where the wall is that seperates the two intake ports....the nice meaty lower part that you really gotta grind down to get it to match the gasket and...... a Small HOLE appeared when i got down to a thicher than desirable spot....alot more needed to be taken off to match the gasket scribe....

what im wondering is....is it possible an air bubble was in the cast and thats how this small HOLE developed? Or do water passeges run between that wall that seperates the two intake ports.....

i took a cutting disc to my old LO3 heads and literally cut a huge hunk out of the wall 2 inches deep (same spot on the wall on the 416's) anyways....guess what? the wall is SOLID iron!! as i suspected!!

did the 416 castings have water passages between those two walls?? it wouldnt seem that way , but i dont understand how a hole is in the damn wall! i mean its small, can prolly be fixed real easily....

now i have taken these walls down SERIOUSLY thin on MY 416 castings....i mean ....3 mm thin, TOO thin....and it never hit a *hollow* spot.....i was under the impression that the seperation walls were solid iron..

is this wrong??? or is this an air pocket?? water passage??

 

should be an inclusion or porosity not a water jacket

 

Sorry..wrong post

 

That does sound really strange... I haven't done anything in the way of head work myself yet, but I have never heard of that before, and i've read alot of posts on the 416 heads being modified as you were doing.

I think you are correct, you probably found one with a pretty big casting flaw in it.

Question: is it like this on both heads you were doing, or just the one?

 

would this pic be helpful..these are unported 416's Is the area in the middle what you are talking about?

 

yes, the wall that seperates the two intake ports, sorry if i was unspecific earlier, i was runnin on NO sleep and had been working for 18 hours.

and like i said, i felt SO bad about seeing that hole i immediatly went home and grabbed a perfectly good LO3 head , and literally cut that whole wall out to look for a water jacket(well, not that they were good to begin with, its still LO3 lol)

now, as i said before, i have done this previously, im not unexperianced....and this shiocked me pretty badly.

i mean there was plenty of *meat* left to be taken away to even get it to reseble the gasket scribe.

and of course this happened on the LAST intake port i did, not the first.

the 416s that are on my car were heavily ported and polished, i took that wall down so thin it was crazy....and i never came across a *hole* or anything of the sort.

in fact the part i felt VERY comfortable about doing was the gasket matching because its hard to mess up and there are no water jackets you could accidently hit.

the part that always scared me was the short side radii, wher eyou COULD hit the collant passage.

so i just had to ask, because this freaked me out, they arent MY heads and i felt horrible about seeing that happen to a good friends head when i was just trying to help. i thought i hit the pasage and ruined it.

so if there is definatly no water passage it should be safe to spread some type of exhaust manifold epoxy stuff over the hole and itll be fine, seeing how it reallt isnt under pressure as a coolant passage would be.

 

heh...man seriously its ok...i mean had i been doing that head I would have hit the same mofuggin thing and prolly made a bigger hole that the pin hole size that is there now...I mean honestly...plus seems like from what is being said it is a casting flaw as we suspected and as we chatted about GM would be even dumber than we give them credit for to have put a water passage there...not to mention the fact that within a year it woulda been clogged and unused...I really thing it was jsut some kinda casting flaw of some form that happened on the head...Ill work on the other one soon as I finish getting this house and stuff together....and see if that same port on the other side has the same thing as well...