Potential problems for head install

ZX2 Dedicated Discussion Problems, Parts and Diagnosis.
1

I’ve recently installed an Essy 2.5 head and had some issues with it. Thanks to Roush for his advice during my install.

I was requested to do a little write up to let people know of the potential problems that may occur during a head swap (or at least the problems I ran into).

First and foremost was the idler pulley, or lack of one. I have a 98 and the Essy head was a 02, there was absolutely no upper idler pulley on this head. From what I’ve been able to guess it may have been an oversight during the build of it. The easiest way to overcome this problem is to simply take it somewhere if you don’t have the tools or just drill and tap the head where the idler pulley should be. Another issue that I ran into was the fact that the head also needed some doctoring to fit my stock cams. Again I had to take it somewhere to have shims made. As far as fitment goes everything seems to have bolted up just fine and the car seems to be running pretty good now that the head is installed. I should mention that the fine tuning will be done this week on a dynojet using my PRP XCAL2 (yay SCT).

Things that may be of interest to anyone doing a head swap.

#1 the year of the head (a build date is located on the exhaust side by the 3rd outlet)

#2 if you are buying the head used, make sure you have it checked for cracks, the easiest thing to do here is take it to a machine shop and have them pressure test it and look for cracks.

#3 be prepared for the extra cost or labour (Canadian spelling) of getting the clearances set for your cams.

#4 depending on the year of the head and the engine you’re attaching it to, you may have to drill and tap for the idler pulley.

This is all for now. I’ll answer any questions if you have any and if I think of any other quirks that I ran into I’ll add them to this post.

Thanks to all who aided me in this project. I’ll be sure to post some numbers once the dyno is done

2

if you want to fix the lack of idler pulley if your refering to the timing belt you the setup off of a focus and it will work fine the zx2 and focus both use the same timing belt the only difference is the idler and tensioner pulley set up hop this helps…jayco

3

Glad everything worked out for you. I’m happy i was able 2 help

ill add this to the new section on the home page

4

On a early to late or late to early head swap the best method of taking care of the idler issue is putting the idler and timing cover backing plate that corresponds to the head.

the early heads used a 48mm diameter idler pulley (the one directly below the exhaust gear) and later ones use a 60mm pulley.

the idler bolt hole location is different for either head as well so the opening on the metal timing cover backing plate will also be in a different location.

i’m sure that esslinger head did have a bolt hole, but it was most likely larger and in a different location, being covered up when the timing cover plate was laid over the head.

rob