1.Engine - general description
2.Work which may be performed with the engine installed
3.Engine repairs and alternatives - special note
4.Engine - removal
5.Engine anciliaries - removal
6.Engine - removal (Turbo)
7.Engine anciliaries - removal (Turbo)
8.Engine flywheel - removing, installing, and component replacement
9.Timing belt - removal and installation
10.Engine lubrication - general description
11.Engine oil - checking oil level
12.Engine oil - changing the oil and oil filter
13.Oil pump - removal and installation
14.Crankshaft front oil seal - removal and installation
15.Oil pan and oil pickup - removal and installation
16.Oil pressure sensor - removal and installation
17.Oil pressure sensor - testing
18.Cylinder head repairs and alternatives - special note
19.Cylinder head - removal and stripdown
20.Cylinder head - measurements, checks, and overhaul
21.Cylinder head - assembly and installation
22.Cylinder head - adjusting valve clearances
23.Engine block - piston, connecting rod, and crankshaft removal
24.Engine component cleaning and inspecting
25.Engine block - measurements and checks
26.Piston and connecting rods - disassembly, inspection, assembly
27.Crankshaft and connecting rods—measurements
28.Engine block - rebuilding
29.Break-in and maintenance of a rebuilt engine

1 Engine - general description
1 As stated in the Introduction to this book, the engine of the Porsche 924 is a radical departure from those found in earlier exam- ples of the Porsche marque. Not only is the engine mounted at the front in the 924, it is water-cooled.
2 The engine unit is easily lifted from the engine compartment via the lifting loops provided. The loops will be found between the cylinder head and the intake manifold and are held in place by the nuts holding these two units to one another.
3 There are several different versions of the engine produced for the US market and a single type which has been available in the European market. The basic descriptions of these engines will be found in the Specifications Section.
4 There are also two different versions of the Turbo model, one for the US and one for Europe. These differences will not affect the tasks which can be performed.

2 Work which may be performed with the engine installed
1 All work to be performed upon ancillary equipment may be car- ried out with the engine installed. To locate rernoval instructions. check the Table of Contents or the Index of this book.
2 Many basic engine work tasks can easily be performed with the engine instaiied. The rule of thumb to be used here is: if the tasks to be performed do not involve removal of the oil pan or any item wthin the engine block itself, you do not need to remove the engine to perform those tasks.
3 This chapter is organized to give a series of instructions in a constant flow, in the order the tasks would be performed in an engine-removal situation. If the task you wish to carry out is not dependent upon engine removal, but is engine related, clear the surrounding area of those parts which block access to the compo- nent you will have to work on, then follow the instructions in this chapter.
4 Remember to drain the oil or coolant where necessary. If your car is air conditioned, take precautions concerning discharge of the system. Refer to these cautions in Chapter 2 before continuing.

3 Engine repairs and alternatives - special note

This chapter will cover the removal, stripdown, assembly, and installation of the Porsche motor. There are alternative ways to ending up with a complete, rebuilt engine which we will mention. After assessing your abilities. tools, and alternatives. We hope you will make the decision best for your situation.
Machine shops:
Some machine shops and dealers wiil accept the engine from your vehicle for service work. In this way you will save the mechanic's fees for engine removal and stripdown of the ancillanes. You will still have the costs of machine work and parts, as well as (he cost of the mechanic's time. but they will be some- what reduced from the cost of bringing the whole car to the shop.

Exchange/purchase of a long block: Auto parts stores make available rebuilt engines in several configurations. The 'long block' is the most complete, offering a rebuilt engine (crankshaft, pistons. and connecting rods), plus a rebuilt cylinder head (valves, valve guides, springs, camshaft. etc), and may be thought of as being completely rebuilt from the camshaft cover to the oii pan. These units are expensive taut. when compared against machine work and the cost of 'down time', can be considered quite reasonable.
Exchange/ purchase of a 'short block': The short block consists of a rebuilt crankshaft with replaced pistons and connecting rods. They are complete from the top of the engine block to the oil pan, but do not include the oil pan or cylinder head in the purchase price.
Purchase of a 'master kit': The master kit consists of proper Sized pistons and connecting rods on a reground crankshaft. These are usually sold on an exchange basis.
Purchase of a 'bare biock': The bare block is not a buiit-up unit, but an engine block which has been bored for new cylinders and has the crankshait bearing surfaces sized and cut as necessary. These are usually required in the replacement of cracked, or broken or overbored engine blocks.
2 If you choose any of the exhange/purchase options listed above, remember that your engine number is part of your vehicle's regis- tration. If you change your engine block, make sure to change •hose details on your registration. Failure to do so could prove most embarassing some time when you least expect it.

4 Engine removal
1 Disconnect both leads from the battery.
2 Raise the vehicle and place it on jack stands.
3 Remove the front wheels (Chapter 9).
4 Place work covers on the fenders to prevent damage.
5 Remove the bolts from the lower engine guard and remove the guard.
6 Drain the engine coolant (Chapter 2} and engine oil (Section 12).
7 Loosen the clamps on the various coolant system hoses and rernove them (Chapter 2).
8 Pull the windshield washer hose from the T -fitting on tha hood.
9 Unplug the engine compartment lamp, if installed.
10 Mark the hood location on its mounting brackets.
11 Remove the hood. This will take two people. Have an assistant hold the hood in place while you remove the bolts.
12 Remove the hoses connected to the coolant expansion tank at the ends opposite the expansion tank Remove the nut frorn the mounting strap and lift. out the overflow tank and the mounting strap, after it has been unhinged from the rnounting plate.
13 Slide the windshield washer tank from its mount and place it ahead of the right front wheel well (photo 5.11 Chapter 2).
14 Using a pair of pliers or a special grooved pliers, loosen the damps from the alternator cooling hose and remove it.
15 The battery positive lead is connected to the starter motor via a cable which passes through the firewail. The cable is removed by punching out the protective rubber grornmet from the back side of the firewall into the engine compartment. Pull the cable through, bend open the wire clip securing it to the firewall and unclip it (photo).
16 Unplug the multiple lead plug at the engine wiring harness.This is located next to the ignition coil. Disconnect the wire from termi- nal 1 of the distributor and the ground wire from the ignition coil at terminal 1 (photo).
17 Remove the hose from the brake booster unit to the intake mani- fold. Make sure that the clamps are suitably loosened before pulling the hose loose (Chapter 9).
18 Loosen the clamp on the engine side of the heater regulating valve and separate the hose and valve. The regulating valve and heater hoses will remain in the vehicle when the engine is removed. Loosen the clamp on the engine side of the heating system intake hose and pull it loose (Chapter 2).
19 Loosen the nuts on the throttle cable support and unscrew the throttle cable. Unhook the end of the cable from the operating lever of the throttle housing (Chapter 3).
20 Pull the oil dipstick out and wipe it off before setting it aside.
21 Loosen the damp on the crankcase vent hose at the intake manifold end and pull the hose loose.
22 Disconnect the electrical plug from the mixture control unit. This is installed only on 1978 and earlier models (photo).
23 Remove the molded rubber duct between the mixture control unit and the throttle housing (Chapter 3).
24 Loosen the lock nuts on the clutch adjuster and remove the cable from the adjuster plate (Chapter 6).
25 Clamp the fuel return line at the fuel tank with a standard squeeze clamp (Chapter 3).
26 Using tape and an indelible ink pen mark all of the fuel lines at the mixture control unit and at the injectors. Label all of the plastic hoses for the vacuum systems and the electrical plug connectors on the engine and its anciliary parts.
27 Detach the fuel feed line from the fuel filter and plug the end of the filter to prevent dirt from entering the fuel system. Remove the fuel feed line from the mixture control unit (Chapter 3),
28 Remove the fuel lines from the fuel distributor and set the lines aside. Place the banjo bolts in an out-of-the-way spot and dispose of the metal seals. These must be replaced when the lines are con- nected (Chapter 3).
29 Remove the electrical connector from the fan and pull the clip from the fan shroud (Chapter 2).
30 Remove the cooling fan motor and shroud (Chapter 2).
31 Remove the air filter housing and mixture control unit (Chapter 2).
32 If your vehicle is air conditioned, it is not necessary to discharge the system if the unit is of the factory type (Chapter 2). If your air conditioning system is of the aftermarket-supplier type and manu- facture, check with that company or its representatives to see if the system must be discharged. Note, nevertheless, that discharge of the air conditioning system should only be done by a qualified air conditioning technician with the proper tools and equipment. For air conditioned vehicles with factory-type systems, perform the following tasks. If your model is not in this group, move to paragraph number 36. 33 Loosen the V-belt on the compressor and remove it (Chapter 2).
34 Remove the compressor from its bracket and carefully lay it aside. Do not attempt to disconnect the compressor hoses. The contents of the hoses are under pressure and could cause injury. If the hoses are loosened, the system must be evacuated and recharged by an air conditioning specialist.
35 Remove the nut which holds the refrigerant hose bracket to the engine mount.
36 Install a homemade wooden support block at the front tunnel reinforcing brace so that it supports the central tube (Chapter 6).
37 Remove the exhaust gas recirculation line from the exhaust pipe and the EGR filter (Chapter 3).
38 Remove the 'Thermag' nuts which hold the exhaust pipe to the exhaust manifold (Chapter 3).
39 Remove the nuts and bolts from the front exhaust pipe to prim- ary muffler/catalytic converter flange and remove the forward exhaust pipe (Chapter 3).
40 Remove the sheet metal guard installed above the front pipe (Chapter 3).
41 Remove the clamping bolt from the universal joint at the bottom end of the steering column and pull the clamp away from the ser- rated end of the steering pinion (Chapter 6)
42 Remove the bolts from the front crossmember and also remove the bolts from the steering stabilizer mounts on the frame. Carefully tower the crossmember and allow it to rest on the compression of the MacPherson struts of the front suspension (Chapter 10).
43 Roll your engine lift into place. Attach a lifting chain to the front and rear lift straps on the engine and raise the engine lift to put tension on the chain (photo).
44 Make a survey of the entire engine compartment. Mark, then disconnect, any electrical connectors, hoses, or other connections you may have missed before. Do not unbolt the engine mounts.
45 When you are sure that all connections except the engine mounts have been disconnected, place several blocks of wood between the crossmember and the engine. This will enable the oil pan to clear the crossmember during engine removal. About 3 to 3 1/2 inches of wood blocks should be sufficient, but too many blocks of wood will bend suspension pieces. Do not force wood blocks into place, or try to get the crossmember to lower any more than it will under gentle pressure.
46 Remove the entire left-hand engine mount, first from the body and then from the engine. Remember, the left-hand mount is the mount on the driver's left (photo).
47 Remove the bolts from the engine bellhousing (Chapter 6).
48 Remove the bolts from the body end of the right-hand mount.
49 On vehicles with automatic transmission, it is necessary to remove the inspection cover from the bellhousing and remove the bolts which hold the rubber/metal damper to the flywheel. Turn the engine with a socket applied to the bolt on the center of the oil pump pulley. Loosen the bolts two turns each In a cross pattern.

5 Engine ancitlaries - removal
1 Before beginning the engine stripdown, clean your work area and make sure that you will have adequate and clean storage space.
2 Make a walk-around inspection of the engine. Check that all hoses, lines, and electrical connections are marked for easy installation.

6 Engine ~ removal (Turbo)
1 Disconnect both leads from the battery,
2 Raise the vehicle and place it on jack stands.
3 Place fender covers on the fenders to prevent damage.
4 Remove the front wheels (Chapter 9).
5 Push the positive cable of the battery into the engine compart- ment (Section 4.15).
6 Disconnect the wiring harness plugs at the firewall. Disconnect the wires from terminals 1 and 4 of the ignition coil. Loosen the clamp holding the ignition coil to its mounting bracket, remove the coii and set it in the tray formed by the firewall and dashboard bulkhead.

7 Pull off the windshield washer hose at the T-fitting on the hood.

8 Unplug the engine compartment light.
9 Remove the hood (Section 4.10 and 4.11).
10 Loosen the clamps and remove the molded rubber boot from the pressure ducting and the mixture control unit (Chapter 3).
11 Remove the bolt on bracket for the throttle cable adjuster, unhook the cable from the operating lever of the throttle housing and move the cable and adjusting bracket aside (Chapter 3).
12 Loosen the clamps and remove the vacuum hose from the intake manifold to the brake booster. Remove the entire hose along with all parts connected between the two ends (Chapter 9).
13 Pull the rubber hold down straps off the air cleaner housing and remove the upper housing and the air cleaner element. Dispose of the element and replace it with a new one when you reassemble the engine.
14 Remove the molded rubber boot from the mixture control unit and the air filter housing (Chapter 3).

8. Engine flywheel - removing, installing, and component replacement
1 The flywheel may be removed with the engine installed in the vehicle by removing the clutch bellhousing and sliding the trans- mission to the rear (Chapter 6).
2 The flywheel is held to the rear of the crankshaft by six bolts. These should be loosened about three turns each in turn, using a cross pattern (photo). When all of the bolts are completely unthreaded, remove the bolts and six-holed washer.
3 Remove the flywheel by grasping it firmly with both hands and pulling it off the crankshaft (photo). Do not drop the flywheel.
4 There are two versions of the center needle bearing which Porsche calls Version I and Version II (Fig. 1,2). The Version I bear- ing may be replaced by a Version II bearing.
5 The bearing should be checked for grooving, tightness of the needles, and the general condition of the bearing surfaces. If the bearing needs replacement, it may be pulled from the flywheel with an appropriate puller. This procedure can be performed with the flywheel in the vehicle by removing the clutch disc and pressure plate.
6 Installation of the new needle bearing may be done with a socket and mallet. Drive the bearing into its sleeve.
7 If the bearing sleeve is found to need replacement when the bearing is removed, it may be pulled out with an appropriate puller. and its replacement driven in with a socket and mallet. If aversion II sleeve is used, install the new seal after the needle bearing is driven into the bearing sleeve.

9. Timing belt- removal and installation
1 The timing belt may be removed and installed while the engine is in the vehicle by removing the alternator and A/C compressor V-belts and the timing belt cover. The remaining procedures are for both in- stalled and removed engines.
2 Turn the large bolt in the center of the oil pump so that the stamped dot on the upper timing belt pulley aligns with the pointer on the camshalt cover (photo).
3 Loosen the nut on the timing belt tensioning pulley and remove the bolt and the pulley. Remove the timing belt.
4 Installation is the reverse of the removal procedure, if the engine has not been rebuilt or turned over while the belt was removed.
5 If you have just rebuilt the engine, turn the engine via the center bolt of the oil pump so that the notch on the V-belt pulley aligns with the pointer on the oil pump.
6 Align the pointer on the camshaft cover with the dot on the timing belt pulley.
7 Install the timing belt. Install the timing belt tensioning pulley