Dart Head ISSUE FIXED
04-04-2006, 11:10 AM
#41
Originally Posted by gollum
I have one more complaint about the as cast Darts. The intake seat is cut roughly .050 deaper than the exhaust seat leaving a very sharp edge for intake air/fuel mixture to cross over at low valve lifts. Dart should use a rounded outer edge seat cutter to clean up this area during manufacturing. While visiting my local Summit store I inspected other heads on display that had their seats cut using a rounded outer edge seat cutter during manufacturing. I am sure Dart's future CNC program will clean up this area but until then Dart needs to use a rounded outer edge seat cutter.
I also called Dart and ask what was the free drop of 205's @TDC on the intake valve using OEM gaskets. He simply did not know
I also called Dart and ask what was the free drop of 205's @TDC on the intake valve using OEM gaskets. He simply did not know
You gotta realize that the step there isin't hurting anything, and it prevents the exhaust from dilluting the intake charge during overlap periods where the exhaust tuning is not optimal, say around 3500rpm. You have to realize that this is a as cast head that has some production tolerances to deal with.... and you are getting it at a hell of a price in comparison to the competition. Yeah they could use a different cutter, but it's not like this trait has not been looked at before, the VJ they put in the heads is what they feel is the best one for performance and wet flow.
As for the free drop. Well that's another area that you have to realize this is a production part. To get the chambers to 62cc sometimes they have to move the valve job height and that could change the free drop easily. So there is a tolerance for the free drop that you can't just say works for every head. You really need to get the heads and measure what your head has anyways.
Bret
