03-21-2007, 10:22 AM
So I got another SVT Cylinder head in today. That thing is kind of strange... Why does the combustion chamber have a wierd divot in between the intake valves and outside peremeter of the cylinder. I don't imagine that promotes very good complete combustion.
I also noticed that the ports have very rough edges on them. I don't know very much about porting heads but I would imagine that having these ports smooth would help. Or does the rough casting edges help promote turbulance and mixing?
03-21-2007, 10:26 AM
I think you want smooth exhaust ports and rough intake ports
I wouldn't be complaining about the svt head, it outflows the ford racing one lol
03-21-2007, 10:39 AM
I'm not complaining about it. I just think it's a little bit odd. I know why the ports are rough from the casting, but the wierd divot thing puzzles me...
Any Cyl head experts want to elaborate on SVTs plan here? lol
03-21-2007, 04:21 PM
Great question -
I had to go ask. Not something I'd noticed before.
Here's how it was explained to me. The divot helps to improve flow over the standard ZETEC head by channeling air/fuel directly into the combustion chamber. The divot helps to create a "vortex" effect that more efficiently mixes the air and fuel to allow for increased compression (Increased from 9.3 to 10.2).
OK, like you I thought "Doesn't that create a gap in the valve that would allow compression to leak out?" Not so much because the valves/valve seats are designed to compress and seal off the divot.
So, that explains the divot, but I am iffy on the compression leak explanation.
I'm not a cylinder head expert. I send them out to folks who know.
Not sure this helps, but maybe it does a little.
03-21-2007, 04:58 PM
Well the thing is that this is a DENT in the combustion chamber. It's near the cylinder wall, where it couldn't cause a compression leak. It would, howver, drop compression as it is a DENT in the combustion chamber. I don't get why they would put it there...
I'm not sure if I am making sense so I'll try to post some picture tonight.
03-21-2007, 08:43 PM
What is that?
03-23-2007, 09:25 AM
*In my best Cliff Claven voice*
UUUUH.. yeah, that would be the point of entry for the uhhh... flux cowherwumper as it mates to the cododdling pin assembly that is necesarry to aahhhh...activate the turn signals....
Yep. That's it.
Seriously, I don't have a clue. I'll take the pick and forward it on to the guys I work with and try to get an answer.
03-23-2007, 09:58 AM
Yeah I'm very puzzled by this thing....