How to Rebuild a 911 Cylinder Head. Lesson 8, Reassembly

Bottom view of Porsche air-cooled motor

Lesson 8 You have made it to the last lesson on the 911 Air-Cooled Cylinder Head, reassembly. As we built these lessons we showed you all of the processes involved. Often we tried to show you how to work with the old components and bring them back to life, or at the least test them. […]

How to Rebuild a 911 Cylinder Head. Lesson 7, Resurfacing.

A sprinning head in the lathe

Welcome to lesson seven in this eight-part series. In this lesson on resurfacing, we show you one of the last steps before the heads are re-assembled. We show a 2-liter head and a 2.7-liter head in this lesson, as they have different sealing surfaces. Resurfacing the Head Gasket Sealing Surface Re-surfacing the head gasket sealing […]

How to Rebuild a 911 Cylinder Head. Lesson 6, Replacing Valve Seats

Old seats removed from the cylinder head

When to replace your valve seats. A valve seat can only be cut so many times before they are too deep into the head. The valve will be in the wrong spot for the valvetrain when the seats have worn out. A 911 cylinder head is made of aluminum. This is a soft metal and […]

How to Rebuild a 911 Cylinder Head. Lesson 5, Cutting Valve Seats

Cutting Valve Seats

We show you how to cut the three-angled seat in your cylinder head. The work that you did to the valves in lesson 2 comes into play in this lesson. By cutting the valve seat, we will match the valve face and create a good seal between the two. A good seal is essential for […]

How to Rebuild a 911 Cylinder Head. Lesson 4, Valve Guides

Measuring a Valve Guide

911 Valve Guides The valve guides in the Porsche 911 Cylinder heads are consumable. The guides will also experience a lot of wear. There is constant friction between the guide and valve stem and the valve-train geometry puts even more side pressure on the guide. Porsche has always used a bronze guide. The bronze has […]

How to Rebuild a 911 Cylinder Head. Lesson 3, Valve Springs

Valve Spring in the head

Air-Cooled 911 Valve Spring Valve springs control the valvetrain. It is valve spring pressure that forces the valves to stay in contact with the rocker arm. Without the proper spring pressure, the valvetrain becomes uncontrollable. Not enough pressure and you can get valve float when the valvetrain gear loses contact with the camshaft lobe. Too […]

How to rebuild a 911 Cylinder Head. Lesson 2, Intake and Exhaust Valves

Dirty intake and exhaust vales on the bench waiting to be cleaned

Intake and Exhaust Valves This is Lesson Two from an Eight part series. In Lesson One, we covered the cleaning and disassembly of the cylinder head. In this lesson, we are all about the intake and exhaust valves. When the valves first come out of the heads they are very crusty. There can be a […]

How to Rebuild a 911 Cylinder Head. Lesson 1

How to rebuild the 911 Cylinder head Part 1

When it comes to the Porsche 911 cylinder head you will rarely find a set that has been untouched. Follow along with this 8 part series to fully understand the air-cooled 911 cylinder head.

Technical Service Bulletin Cylinder Head Stud Exhaust Sides

Subject: Cylinder Head Studs Exhaust Side    Models:911/930 1977 -> Bulletin Number: 77-04 When cylinder head is removed during major engine repairs, include the following operation: Remove cylinder head mounting studs on exhaust side of crankcase (6 on each side). Install “Dilavar” studs (shiny), Part Number 930 101 170 02 Note: Always replace studs on both […]

Technical Service Bulletin Cylinder Head Torque

Subject: Cylinder Head Torque      Models: 911 Carrera 1978-1986 Bulletin Number: 86 – 13 The torqueing procedure for  the cylinder head nuts has been changed as of production date June 30, 1986 from engine numbers: 64G07073                                                         64H00089 Work Sequence: Torque all nuts to 15 Nm (11ft. lbs.) in proper order. Torque all nuts an […]