This write-up will explain how I changed my duke from this:
to this:
Getting a Super Duty Valve cover on a stock duke takes a bit of doing -- especially if you want all sensors and emission controls in tact after the change.
The most obvious thing you can tell from the picture above is that you need to change the air cleaner. Basically, what you need to do is remove the snout, invert it, and mount on the side. My first attempt is not as good as I'd like it to be, so I think I'm going to do it again, and perhaps write that part up then.
The stock valve cover has a depression in it that the EGR valve leans into. Since I wanted my engine to still have an EGR valve after the change, I had to do two things to make it fit with the super duty cover. The first was to make an adapter plate to move the intake manifold back a little. To do this, I started with a chunk of aluminum 18" by 3" by 3/4", which I purchased from
speedymetals.com:
(I had already started working on it when I took the picture.) When I was done, it looked like this:
To cut it out, I drilled holes at the corners of the large openings, then drilled a lot of little holes between, then cut with a saber saw, and then smoothed it with a rotary rasp on a drill press. I had to do a little tweaking after taking the picture, but that's basically the finished product. I used this piece between the head and intake manifold, with two intake manifold gaskets, and 50mm long bolts instead of the original ones.
When test-fitting the valve cover, I found two things in the way, indicated in this picture:
There is a temperature sensor that is too close, and a stud on top of one of the head bolts that is too high. The stud holds down a vacuum line and two ground wires. I had to cut a notch in the side of the valve cover to clear the sensor:
(You can see where my rasp slipped while I was cutting, but it doesn't show. And I cut the notch a little too deep and nicked a small hole in the cover, so I put JB Weld on the other side.)
I filed down the stud, and moved the ground wires to another position, as shown in this picture:
I screwed the sensor down a little farther than it was, because the bottom flange of it also hit the cover. And, after I filed down the stud, I used it to hold the vacuum line only.
Moving the intake manifold back alone isn't enough to allow room for the EGR valve. The way it mounts on the manifold, it leans towards the valve cover, so I had to cut off the base of another EGR valve to make a wedge that would allow the EGR valve to sit upright. The wedge looks like this:
When the manifold is mounted with the spacer, wedge, EGR, and throttle body, it looks like this:
I have to use an after-market EGR valve only with this setup, because the stock ones sit too low, and hit the throttle body. But I have been using an after-market one anyway for a couple of years, and the car passes emissions with flying colors with it. Notice how the intake manifold shines -- I wire brushed it.
I had to cut a small nick in the bottom of the air cleaner can to allow for the vacuum nipple on the EGR valve. This cut is outside the air filter, and the only detrimental effect of it is that it allows a little warm air from the engine compartment to be pulled in.
A problem with moving the manifold back is that there is a brace between the manifold and alternator. I solved that by attaching a small piece of metal to the brace to move it's attachment to the alternator over by 3/4". The modified brace looks like this:
One other problem I had to solve with this setup is that one of the deck support springs would hit the cover if I tried to close the deck. I solved this by drilling a new hole in the spring link to move it up a bit, as in this picture:
You have to be careful working with these springs -- they're under tension. I wedged a piece of wood between the spring and deck while making the modification.
Because the air cleaner sits closer to the trunk wall after this mod, you probably should have poly dog bone bushings to keep the engine from moving too much. That's what I have, and there's no indication that my air cleaner has so much as tapped the trunk wall since doing the mod. And the spacer on the manifold seems to have no detrimental effect on performance. If anything, the engine seems to run a little better with it.
