Various Ford Escort manifold parts.

There are a few options and modifications available for the 3rd gen Ford Escort SPI manifold.

• Cleaning: Whenever taking the IM (Intake Manifold) apart, usually it will be extremely dirty inside with a mixture of oil and soot caked on the inside of the walls. It's necessary to remove this before doing any porting, otherwise metallic particles will get stuck to the dirt and could later make their way into the engine. One of the best ways to do this is through the use of an industrial degreaser, such as PurplePower, available at any Adance Auto Parts store. The degreaser comes in 5 gallon buckets and only costs 10 dollars. It can be reused many times over but will eventually begin to take longer for the cleaning action due to having a lot of dirt mixed in. It works exceptionally well, and begins to eat the sludge and grease off right away. Moving the part around really helps because the more fluid movement there is the faster and better it will work. However it is not recommended to leave parts for too long in it because they will start to form minor corrosion from the reaction. However even this is not bad and will not damage the parts as long as the corrosion is cleaned off afterwords. It can be seen in the form of a white substance on the intake manifold in the picture below.

  

  To keep the IM clean in the future, eliminating the EGR or the PCV is recommended, the two systems combine oil and soot to foul everything in the whole induction system. At least if the PCV system is kept the oil has no other agents to foul and bind it to surfaces and is usually pretty easy to wipe off with a rag during the next time the part is removed.

• Porting: Due to manufacturing tolerances, none of the various components in the induction system are usually matched up perfectly. This creates ridges and uneven restrictions for the air. Eliminating this vastly improves the air flow. Quite an easy but very time consuming task, porting is best done with carbide bits and a die grinder, then finalized with sandpaper to smooth things out. Following are some examples:

  

• Fasteners: The intake manifold is held by studs which are screwed in with inverted torx studs, fairly easy to replace and quite a good system. The nuts that hold them down are 13mm with attached spinning washers. Generally anything can be used, but losing a few and wanting to replace a few that were rusty, led to finding a company that manufactures the exact same type of nut. They are high quality and last for a long time. See the picture below for details.

  

• Vacuum lines: The vacuum system in most stock vehicles is designed from a manufacturing and bureaucracy perspective. It's quite easy to simplify everything to clean up a lot under the hood and make future maintenance much easier. There are red silicon hose kits on ebay for free, however these actually don't work too well because they require cable ties to clamp them down to the vacuum connections, even if they are pretty. Replacement vacuum hoses can be purchased at any auto parts store by the foot for a very inexpensive price and will work perfectly for this. While the picture below demonstrates the continued use of the vacuum tree that comes stock in Ford Vehicles (very brittle after a while, be careful) eventually it was eliminated all together and the manifold was modified to include all of the vacuum connections. There were less vacuum connections after eliminating many of the overcomplicated emissions systems. In the end the only hoses that remained were to the brake booster and FPR (Fuel Pressure Regulator).

  

• No intake! While on the subject, it's interesting to note that running the car without an intake period is actually very nice because of the following reasons. The length of intake piping usually creates a lag because once the throttle opens a pulse travels through the air and reaches the filter, to begin drawing air. Since the MAF is also closer to the throttle body (pretty much on it) the throttle response is faster as well, because the computer gets the signals that air is being drawn by the TB much sooner. The whole setup is much simpler and does not have as much weight or complexity. And finally, warmer air is drawn from the engine bay while not the best of things for performance, it does help with gas mileage because fuel atomizes better, and the mixture is leaned out based on the readings of the IAT sensor. Note, the throttle body in the following picture is the 3.8 BBK designed for the Ford Mustang.

  

• SPI assembly: The best way to port and rebuild the intake manifold is to take apart the entire SPI assembly is to remove the screws that hold the butterfly valves and remove the entire shaft. This allows for much better cleaning and porting. It was difficult to remove the screws in there to begin with, because they're made to stay in there for a reason. If one of the screws were to come loose from the factory built assembly, and make it's way into the chamber, the engine will be as good as scrap metal. Therefore a screw extractor had to be used, it is a tool that can be purchased at almost any hardware store, which taps itself into the Phillips screw with reverse threads, so as the screw is being turned counter-clockwise, the tap buries itself deeper and deeper and eventually breaks the screw loose. For re-assembly, a few small hex head machine screws were used (purchased from Ace Hardware), along with threadlock to make sure they do not come out. On the back side of the butterfly assembly any parts of the screws that stuck out were ground away for better airflow. This can be taken a step further by grinding away parts of the shaft for better flow, and leaving just enough to hold the butterfly assemblies. Finally, the SPI controller motor can also be rigged to open right away with a switch installed inside the car.

  

• Focus SPI manifold: The stock 3rd gen Ford Escort intake manifold does not have even flow, being a log design the first cylinder will always run leaner due to being the last to get air and the fourth cylinder will run richer because it is the first to get air. While this design does work, it's not the optimal one. Ford eventually did realize this and created an equal length runner manifold for the Ford Focus SPI. These manifolds are harder to find because not too many Ford Focuses came with an SOCH CVH SPI engine. An attempt was made to fit one to an Escort head, and while possible the project is still not complete. This is primarily because Ford changed the bolt pattern of the manifold for no reason. While most of them do match up, there are a few bolts that do not and they raise the concern of having enough force to properly seal and mount the intake manifold to the head. Below are some pictures of the project. The SPI controller is different on the Focus lower intake manifold. One nice thing about the lower intake manifold on the Focus is that it is much lighter and simpler. Modifications were being made to slim it down even more based on the mating surface of the upper manifold, as can be seen in the pictures below. One of the pictures demonstrates a planned modification of cutting away the main plenum and welding on a far simpler one with larger volume, however this is still in the works and the project has been put on hold due to requiring too many modifications. Had the Focus cylinder head been acquired together with the intake manifold this project would be much simpler.

  

  

Also see

• Alex's 98 Escort build, 97 Escort build, and 97 Tracer build (latest) for more examples and application.
• BKK throttle body upgrade
• Idle control valve elimination
• Ford Escort & ZX2 section for the entire index of all Ford Escort and ZX2 related articles.