RobzWorkz #8e: Improving the 328 Fuel System: Intake and injectors.

Hello again FChatters!

My fifth entry for improving the 328 fuel system includes improving the (previously-removed) intake system, the idle air system (under the intake) and replacing the injector bushings.

Some will recall my single injector bushing repair thread:

http://www.ferrarichat.com/forum/showthread.php?t=290194&highlight=injector+bushing


Since then, Geert Jan Schreurs has made the new bushings and associated donuts/O-rings available on his web site:

www.ferrari400parts.com

Also available there are the rebuild kits for the CIS distributor and WUR that I used and will be posting soon. His web site also includes several downloads pertaining to rebuilding these items.

During this thread you will be able to notice that I continued to use the bushing I replaced in the former thread. It is thus my assessment that the bushing was made of excellent material and showed no significant wear over the year of use I fostered upon it. This is a quality part. Of course, I will be replacing all the other injector stuff in full.


The remaining part of this post is a series of pictures showing the removed intake, the air injection/idle lines underneath and associated fasteners.

A few notes should be made herein:

1. Keep track of all fasteners. All fasteners I encountered were steel and were magnetic. Therefore, keep an extendable magnet available for retrieval. Replace fasteners only with like-kind.

2. Don't forget that there are steel ring spacers around the studs between the plenum and the risers and that the gasket there can pick up the spacers when removing the plenum and fall into the risers. For positioning each riser gasket, there is a pin in the plenum flange surface to disclose the gasket position (hole in gasket lines up with pin).

3. If you have kept your throttle cable intact, don't forget #2 above when removing the plenum. I simply removed my throttle cable by cutting it since I was replacing it; this meant that I could remove the entire intake without separating the plenum from the risers...I only had to loosen to provide flex for intake removal. I expect that removing the throttle cable without removing the plenum could be a chore since you must remove the threaded piece from the riser to retrieve the cable intact.

4. If a fastener falls into the intake part of the head, immediately remove with a magnet. It is also possible to retrieve an item with a vacuum cleaner with a small diameter hose attached to the end. Also, do not rotate the engine crank or valve train untill the part is recovered. Before reinstalling the intake, conduct a series of thorough inspections with a magnet, mirror and vacuum cleaner. DO NOT USE COMPRESSED AIR AROUND AN EXPOSED ENGINE!

5. If you believe you lost an item into the head, PM Fastradio for emergency advice.

6. Keep track of all fasteners.
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Remove all the snap rings with a pair of snap ring pliers. You can do this after removing the injectors as well.

Remove old injectors; this can be done by attaching a threaded union to the injector and lifting out with a wrench (I used a close-sized air fitting with good success). After passing the internal donut threshold, the injector should come right out. Don't force too hard...you should always sense the flexibility, or "cushi-ness" of the injector donut...no metal-to-metal feel here. Since I was replacing the injectors, removing this way was sufficient. If you are reusing yours, then consider purchasing or making an "injector remover." This is basiaclly a lever with an injector fitting attached; the lever has a fulcrum to place on the intake body to allow lever force at the injector. I find the a little spit can serve as a lubricant if necessary.

Removing the old bushings was easily done using a C-clamp and a long thin socket. Since the socket could nick or deform a bushing, if reusing (like for the one white one shown) protect the bushing by adding soft tape (duct tape works) to the socket during removal. FYI, I removed the bushing I replaced earlier to inspect it and make room for general cleaning of the riser.

After removal, it's a good idea to keep altogether in a plastic bag.

The thick donuts that retain the injector usually remains in the bushing. Sometimes a donut would come out with the injector....this is a good sign it needs replacement. If replacing, you can remove with a small screwdriver. If not replacing, don't remove at all.

Pics below:
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These pictures show the process. Basically, clean up the metal using solvents and fine wire wheels on a Dremel. If you use the wire wheels on any machined surfaces, be very gentle...if you don't know "how gentle" use a brush wheel that's not metal...you don't want to scar the surfaces.

For some areas where Dremel access was obsured by the Dremel's body, such as the riser insides, I used a brass wire brush and steel wool. Again, be gentle.

For the smaller holes, use Q-tips and pipe cleaners. In some cases, a tooth pic can be used for removing specs. Flanges can also be final-cleaned with 600 grit sandpaper if necessary.

The first shot shown with the Dremel shows a riser piece half done to show the improvement. The shot with both risers shows one done, the other not.


Installing the new bushings is simple. For each, install its o-ring and press the bushing into the machined hole with a thumb. When the bushing is far enough into the hole, install a new snap ring. Reusing the old snap rings is ok as long as they are unmarred, un-corroded and possess flex. New is better and generally affordable.

If you need to tap the bushings in place use a non-metal hammer with soft taps...no hard blows.
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Under the intake plenum there is a tube with 8 flexible lines going into each of the 8 risers. These lines were basically vacuum hose lengths in my 328. I decided to use lengths of the Aeroquip hose used for my evap lines here. I used new hose clamps.

As before, using the AQP hoses may be considered "overkill" for this area. However, be sure to use a long-lasting and strong fuel injection line. Clamps are recommended. This area is quite susceptable for undiagnosed air leakage into the intake plenum and can cause drivability issues, especially at idle.

Also, as can be seen, the alignment of the hose taps on the floating pipe was not symmetric with the taps in the risers. Thus I offset the hose lengths to line these up. The only drawback for my doing this was that the elbow piece going to the cold start injector would twist a little. I was replacing that with my own 2-hose elbow setup anyway and used Black RTV to seal the elbow hose pieces onto the hard elbow piece itself (those elbows are expensive...there's 2 in the fuel system: here and in the aux air line...and, they're not "new" materials either. I completely removed the one from the aix air system because of that). A picture of the 2-hose and hard elbow configuration will be shown after presenting the reinstallation of the intake and cold start injector.
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All is completed with the new injector bushings and idle lines. To finalize this thread, it will be shown the reinstallation of the intake.

Before installation, I freshened the intake plenum.

For all installation flanges, I used Ultra Black RTV (I even used RTV on the flex gaskets between the plenum and risers). Recall, for good RTV usage, apply on surfaces, emplace item onto flange, tighten fasteners to seat but do not torque, wait 1 hour, then torque. For the intake, I chose 18ft-lb (didn't see spec in WSM or Tech man). For CSI, torque by hand (around 5 ft-lb).

After the intake is installed, install the cold start injector and any remaining loose hose ends (AAV line and small blow-by line, as applicable).

See pics below.

All done.
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The title of this thread included the injectors. I was incorrect. It should have said "injector bushings." I installed the new injectors after reinstalling the intake and rebuilding all the CIS hoses. Also, I tested each new (and old) injector for opening pressure, spray pattern and closing/retention pressure. Thus the injector descriptions will be deferred until the testing thread. Also, only install the large donuts when you are ready to install the injectors themselves. Until then, cover the injector openings with tape to prevent stuff from falling in as shown in the last post.

 

Plenum top is VHT red (crinkle not very noticeable on plenum as shown). The rest I will be leaving natural.