I forgot to mention the one experience I had with a wet flow designed cylinder head. I had a customer bring me a 383 SBC that he put the latest and greatest wet flow designed cylinder heads on it. His car consistently ran 10.40's @126 mph with a set of chevy bowtie heads that I ported for him. He done some reading on this new wet flow designed head that was supposed to be better than their competitors heads by 20+ HP (I don't remember the exact HP). So he purchased these heads which had about the same port cc's as what he had on the engine, but a little bigger intake valve. Installed the new heads with no other changes reset the timing back to were it was on the engine originally and ran the car. First thing he said he noticed was the throttle response was a little slower and the drive-ability in the pits was poor. Does his burn out and stages the car and will not come up on the converter like it should. Makes a pass get's his time slip 11.08 @ 120 mph. So he thinks it needs re-jetted for the new heads, makes sense. Pulls a couple of plugs and looks really fat. Jets it down 3 in front and 2 in back. Makes another pass still not happy with the way it feels 11.20's @ 118 mph. Pulls the plugs they are looking better so he thinks well maybe the timing needs retarded a little even though the way the engine was with the old heads it only wanted 28 degree's total. He retards the timing to 26 total makes another pass 11.30's 116 mph. By this time he is think okay I screwed up something loads the car up and gets it back home. Checks for a head gasket not sealing, valve lash, all the things he knew had messed with. Nothing!!! He spent most of the summer trying to get the car the run like it did. Needless to say it never did run the number. He brings me the engine and wants me to freshen it up and tells me the story. When I pulled the heads off the engine the piston tops and combustion chambers were so sooty and still wet that it looked like he was running kerosene or diesel fuel. I tear the heads down and don't see anything way out of whack, but I notice that the short turns have a pretty sharp 90 in them almost a point at the apex. I call the customer tell him that I want to rework the heads before I button the engine up. He gives me the go ahead and I get started. When I put the head on the bench to see were it is at I cannot believe how dirty the port sounds. It's cackling hissing, gurgling the test pressure is jumping about 3-4 inches. The head just does not sound happy at all. I went in and radius ed the short turn blended the bowl and changed a couple of angles on the seat and matched the ports all up and put the engine back together. Long story short I have a very happy and loyal customer now and he picked up another 2 tenths from his original combo and 3 mph (10.20's @ 129). So my one and only experience with wet flow design was not a good one. I'm not saying that it's bad. Just saying it did not work in this situation.
Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!
|