Contour Enthusiasts Group Archives Forums Modifications Zetec Performance re: Zetec head

Hey Paul, how much did you shave off of the head? I'm curious because I just finished working on a Zetec Cougar and the head was shaved 2mm to bump the CR to about ~11.2

I didn't have the full spec's on the internal so I had to guesstimate, so that figure my be off by about .2

The Ford knock sensor is really sensitive and overactive, the car wouldn't rev and the OBDII reader was reporting that the timing was all over the place.

So in the mean time until we get the ECU tuned somehow, I sorta disabled the knock sensor and it made a HUUUUGE difference. I suspect that might be your problem if your cam timing is indexed correctly.

So what I did is unbolt the knock sensor from the block, I then used some primary wire so that the knock sensor still had an active electrical connection to the block while it is physically not connected to it. I then zip tied it to the firewall. You might want to give that a try.

Here is a quick and dirty pic of what I did to the head along with the milling.



The goal was for 160hp at the wheel's NA.

I think the shaving might have been about 3 mm, bringing the CR to 11.5 or more.

Nice job. Thanks for posting images.

A table I have indicates that if you mill the Zetec head 0.025" that results in a CR bump from 9.6 to 10.2. Milling the head 2 mm (0.079") should result in a static CR of about 11.8 !! (As you reduce the CC volume the increase is not linear.)

If you removed material from the combustion chamber the resulting volume would be somewhat larger and you are probably pretty close to 11.2 CR. Did you measure the combustion chamber volume after doing the head work??

If anyone knows of a good automotive machine shop with experience on Zetec heads in CT or in the Springfield or Worcester, MA areas please post that info. I have a Zetec head that needs some machine work and I don't want to trust it to the guys down the street.

Thanks...