924/944/968 Frequently Asked Questions

8.0 Engine

8.1 Where should my oil pressure be at when cold? warm? idling?

When your car is cold, the oil is thicker. Normally this means when you first start your car the oil pressure will be 5 bar at idle. After warming up the car (typically, it takes approximately twice as long for the oil to reach operating range as your coolant does) it should drop to between 2 and 3 bar at idle.

You don't need to worry unless it drops to or below 1 bar. If the oil pressure sender fails, typically the oil pressure will peg at 5 bar as soon as you turn the key to the on position.

8.2 I’m worried about my car starving for oil during hard cornering, is there a fix?

For highly modified vehicles pulling very high cornering G’s, it ispossible that the oil will slosh away from the pickup causing theengine to starve for oil (read: big engine damage). The 89 944 Turbo and S2 have an additional pan baffle to help avoid this problem.This part will fit other 944’s. The Oil Pan Baffle part number is 944.107.389.03 and costs approximately $65.97. This may not fix the problem entirely, but it may help.

8.3 Do I need a special engine stand to hold a 944 motor?

Nope. A "normal" four-armed engine stand works fine. Be careful that the bolts don't go too far into the block or they may damage the mounting points for the bell housing.

8.4 I'm replacing my timing belt, any helpful thoughts?

The following advice is for 924S, 944, and 968 series cars. It's a good idea to get a feel for how the engine turns before changing the belts. Going one full rotation at the crank pulley will give you a good idea of how the engine should "feel". When you've completed the job you will be able to tell if the car is out of time because the resistance will be too high. If you don't know how it should feel, you may end up damaging your valves with your breaker bar.

For final tensioning, the engine should be at TDC minus 10 degrees, to find TDC remove the distributor cap and cam sprocket housing while leaving the wires in place (this is a good time to replace your cap and rotor). You now have a clear view of the timing belt on the cam sprocket enroute to the tensioner and can begin looking for TDC (top dead center). Using a breaker bar half inch drive with a 24mm socket and a mixed bag of adaptors/extensions, turn the engine over at the crank pulley nut until you align the nick in the cam sprocket with the nick in the cam housing. Because the cam turns at a 2/1 ratio with the crank, you must check the flywheel for the stamped "OT". At the rear of the engine from the drivers side just before the firewall, you can peek down and see at least one opening atop the clutch bell housing. Inside is the flywheel which you will see moving if you turn the engine with your left hand. Atop and through that hole will be the letters "OT" when TDC is reached. It will be one of the two times the cam marks align. There is also a mark at the bottom of the flywheel under the car, that will point straight down when TDC is reached. From TDC, turn the crank anticlockwise 1-1.5 cam teeth.

In order to replace the timing belt on the '87 or later cars, you need to remove the self-tensioner assembly which is held in place by 3 bolts you can't see. The 3 you can see, you don't remove. The bolts you need to remove roughly form a triangle around and behind the three bolts you can see (which are for the tensioning sprocket, the one the assembly pivots on, and the one that freezes it in place).

I also recommend getting a good manual (Chilton's or the factory manuals) to assist in this process. Be sure to set the engine to TDC -10 degrees (as outlined above) before removing the belts. In addition to the two reference points mentioned above, there are also alignment marks on both of the balance shaft sprockets. Make sure that everything is aligned before removal. Once this is done, R&R the belts (or go further & replace the tensioners/rollers if you are doing so at this time). When replacing the belts, make sure that you keep the reference marks aligned! Being off on the camshaft sprocket will result in valve damage; being off on the balance shaft sprockets will result in much vibration from the engine. Tighten the belts, then use the special tension gauge to adjust (part $ P9201, cost around $500). I have never seen a consensus on the actual setting used...My local Porsche repair shop said 4.0 on the timing belt, 2.7 on the balance, Jim Pasha wrote in excellence 4.0 on both, and Chilton's had something different (4.0-4.6 balance, 2.0 timing I think). I went with Jim Pasha's advice & set both to 4.0. Afterwards, I could hear the balance belt whirring, so I reset it to 3.2. This seems to have fixed the noise. Just my 2cents... Once you have an initial adjustment, use your breaker bar & turn the engine over one full revolution. Check the tension again & adjust if necessary (this step is necessary is that it will remove slack on the belts caused by the belt binding on the sprockets or tensioners. Keep in mind that the belts need to be checked & adjusted at 2000 miles, earlier if necessary. Aftermarket belts have a tendency to stretch much earlier that the factory versions, so they may need to be checked sooner. The timing belt should be set to 2.7 at the 2000 mile mark.

On a 924, the procedure is more straightforward and is documented in the Chilton's, Haynes', or factory workshop manuals. The tensioner tool is not required for these cars.

8.5 How do I tension the timing belt an 87 or later car using the built-in tensioner?

The self-tensioner on '87 and later 944, S, Turbo and S2 allows accurate tensioning of the timing belt without tool P9201. The assembly achieves this by means of a spring whose preload is fixed to create the proper tension while the engine is cold. Loosening the correct bolts frees the spring up to do this task before retightening.

The entire job is done from above the engine. You gain access to the belts by removing various things depending on which 944 variant you have. The 944, S, Turbo and S2 are all a little different. In each case you are removing hoses or boxes which carry air. The 944 has a coolant hose which may get in the way. The Turbo needs to have some of its plumbing removed.

Once you have a clear view of the top portion of the two piece plastic belt housing, remove the 10mm bolts holding it in place and finagle it out. You now have a view of the tensioner assembly and belts. The belt should look fresh and not show cracking or shining.

The next phase would, by some, be considered optional. The factory workshop manual states that the engine should be at TDC (top dead center) minus 10 degrees (about 1-1.5 cam teeth) before the tensioning spring is released. This is because belt tension isn't always the same between the cam and crank as the engine turns. It varies slightly. If being unable to find TDC discourages you, you might still be better off releasing the spring than chancing a loose belt. A description locating TDC is available above in the timing belt replacement tips.

The tensioner is the alloy arm roughly 6 inches long with three bolts sticking out. If you look behind it, you'll see the spring. The assembly swings on the top bolt, has an elliptical opening on the locking bottom right bolt and retains the tensioning sprocket with the bolt on the left.

Loosen the top 13mm bolt. Now, while watching the tensioning sprocket for movement, loosen the locking 13mm nut. The sprocket should either not move or move slightly to the left and up against the timing belt. If no movement occurs, take a 17mm closed end wrench slip it on the sprocket bolt and put pressure down on the nut to make sure it is not seized/jammed. Lock the locking nut to the designated torque (warning: it’s not much). Install everything back at the proper torque and you are all set.

8.6 What's all this about the infamous belt tensioning tool P9201?

Because of the catastrophic nature of timing belt failure (valves being destroyed), there is very little room for error when tensioning the timing belts. The P9201 tool costs approximately $500, and it appears there is no alternative tool (the search for such a beast has become the holy grail of water cooler do-it-yourselfers everywhere).

The 1987 and later cars have a built in tensioner for the timing belt. However, it is still recommended that the tool be used on the alternator and A/C belts. Some folks use the "by hand" tensioning method, this requires a good "feel" for how tight the belts should be but it's your engine and your decision.

As of 10/96, the cheapest price available on the P9201 was $425, available from Engine Builders Supply Co. (they are on the web). Average price is around $500. The tool should also be used to double check the self adjusters on 87 and later models (better safe than sorry...)

8.7 I'm experiencing a random power loss in my Turbo, what's up?

This appears to be a common problem, especially on the 89 Turbos. The normal boost is 1.2 bar. If everything is operational, it will go to slightly above 1.8 bar. The most common problem is a bad connection due to corrosion on the throttle position switch (located on the throttle body, forward of the intake manifold). On one side is a cable that controls the throttle opening, and the other side is a black plastic device that reads the throttle position. The connection to this device can become corroded. Typically moving around the connector a bit will fix the problem temporarily. Disassembling the connector, cleaning and putting on a coat of dielectric grease on it will fix it semi-permanently.

8.8 My 924 is very hard to start when the engine is hot

This is a common problem with the 2.0 litre 924-series cars. Porsche issued a series of upgrades to the fuel delivery and engine management system that help correct the problem. They are described in several factory service bulletins:

Another source of hard-start problems for the 924 is its warm-up regulator. The warm-up regulator on the engine manifold and air bypass right in front of it are the two likely suspects, especially if the problems happens at cold start as well as hot start.

Also check the cold start injector on the back of the manifold as it works even when the engine is warm to inject fuel to aid in start. When warm, it does not stay on as long as when cold. The best thing is to turn on the ignition with a cold engine, but do not start the engine. Pull the electrical plug and check for 12 volts (approximately) at the plug. If there is no power, pull back the rubber boot and look for a broken wire - very common.

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