Tech Articles 911 1974-89

Welcome to our Technical Articles section. We’ve gathered a vast collection of useful articles to help you perform many repairs and upgrades on your Porsche 911. Save money by doing your own work and perform the repairs using the information we’ve provided here.

If you’d like to support the site and submit your own Technical Article please email sales@design911.com

Expandable Oil Return Tube Kits The principle point of failure are the two seals on each end. After many years of service, the seals get old, and begin to leak. The good news is that there is a relatively easy fix for these leaking tubes. Unlike the 914 oil return tubes, there are no pushrods running through them. To replace the oil return tubes with factory original ones, you need to take off the heads. However, there are replacement expandable tubes that will allow you to replace a tube without even taking off the valve cover. This technical article will detail the process of removing the old tube and installing a new expandable tube.

Fuel Pump Replacement Porsche 911 engines need a steady supply of fuel at the correct pressure for good performance. If the hum from your fuel pump is getting louder, it may be a sign of imminent failure. When you order your new fuel pump, be sure to get two new copper sealing rings.

CIS Pop Off Valve Installation The pop-off valve, which is also called a backfire protection valve, is a good modification for 911s with the Continuous Injection System (CIS). In the event of a backfire, which is not uncommon with these cars, the force can crack the airbox.

Retrofit Heat Exchangers The results of upgrade.
Increase in horsepower. There have been claims of anywhere from 10-30 horsepower. There is definitely an increase especially in the higher RPMs. A rough guesstimate would be teens to twenty. Flatter torque curve. The torque begins earlier, and is smoothed out throughout the RPM range. The SC lost some of the head jerking mid-range torqueiness, but there is now a smoother pull through all RPM The clutch chatter went away. Increased torque and also the car no longer backfires, and it also does not smoke.

Installing Short Shift Kit 911 1974-76 The following are detailed instructions on installing a Factory Design Short Shift into a 1978 911SC. They should be applicable for model years 1974 to 86.

Turbo Tie Rod Kit installation The original factory 911 1974-89 tie rods use rubber dampers which can make steering feel spongy, especially with age. Upgrading to 911 Turbo tie rods will give your car firmer and more responsive steering. Installation is a straight-forward process, and can typically be performed in an afternoon.

6 Pin CDi Spark Box Unit  Remove the old ignition module from the car according to the shop manual for this car. Perform a bench check of the module according to the manufacturers specifications. Perform any maintenance procedure needed, if the bench check procedure indicates so, to prevent damaging the new ignition module upon its installation. NOTE: On some cars, the relay panel where the ignition box is located must be unbolted from the car so that the nuts can be held while the bolts for the ignition box are unscrewed. One of the screws for the relay panel mounting also holds the braided ground strap that provides the ground for the relay panel. This ground strap can be easy to forget to hook back up because when it is removed from the relay panel it will fall forward between the fuel filter and fuel accumulator where it cannot be seen. It is extremely important that this ground strap be reconnected when the relay panel is bolted back to the car. Failure to reconnect this ground strap may result in damage to the car or your new ignition box.