Mark944na86

This is an updated and annotated version of Clark's ENG-05 Camshaft (Timing) Belt and Balance Shaft Belt Removal procedure I made for the S2. I was going to send this Luis because he is about to undertake a belt job on his S2 cab for the first time, but I thought posting that here might make it useful for other S2 owners who haven't yet undertaken this job.

Note, all my comments, corrections, and annotations are italicised and in square brackets []. -Mark

ENG-05, Camshaft (Timing) Belt and Balance Shaft Belt Removal

(Updated by Mark944na86 for 944 S2 -- Feb 2009)

Tools
• Jack stands
• Floor Jack
• Metric Socket set
• Metric Wrench set
• Flywheel Lock (P9206) [or equivalent, e.g. ArnnWorx tool. -Mark]
• Balance Shaft Pin Spanner (P9200) or equivalent (if removing the balance shaft sprockets. [also useful for compressing autotensioner spring. -Mark])
• Gear puller (if removing the crankshaft gear) [Penetrating oil and "wiggle" method can also be used to remove crankshaft gears and pulleys if gear puller not available. -Mark]

Other Procedures Needed

• ENG-03, Flywheel Lock Installation
• ENG-13, Locating and Setting Engine to Top Dead Center (TDC), Cylinder 1
• AF-01, Air Filter Housing and Air Flow Sensor - Removal and Installation
• IGN-01, Distributor Cap and Rotor Replacement

Refer to the Timing and Balance Shaft Belt Drawings for details:

For 1987 - on 944 models with spring tensioners.

Procedure

1. Disconnect the battery negative lead.

2. Position the number 1 piston to TDC.

3. Disconnect the battery positive lead.

NOTE

It is possible to remove the timing belt with out removing the balance shaft belt gear on the crankshaft. However, it is extremely difficult to install the new belt with the balance shaft gear in place. Rather than risk damaging the belt, I prefer to install the flywheel lock and remove the balance shaft gear. If you choose not to, the steps associated with installing the flywheel lock, removing the crankshaft pulley bolt, and removing the power steering and balance shaft gears may be deleted. [Also note, if you are planning to also attend to front oil seals and/or water pump, the steps involving removing the crankshaft gear assembly are necessary rather than optional. –Mark]

4. Using ENG-03, install the flywheel lock. [See note above. Also note that the S2 has one 10mm hex socket head bolt on the starter motor, and one standard 19mm bolt. I used a big 10mm hex key and my foot to get this off. -Mark]

5. Remove the alternator and power steering pump belts.

6. On Turbo models, remove the turbocharger outlet line to the intercooler (Large diameter aluminum tube to which the air filter assembly is clamped).

7. Using AF-01, remove the air cleaner housing and air flow sensor assembly as a unit. [On an S2 only the air flow sensor assembly (AFM) needs to come out – undo two hose clamps, the Bosch sensor connector, and three bolts under the AFM. Also a good idea to get more working room on an S2 is to remove the radiator fans – three bolts on the bottom, and three along the top – the third on the top is under the AFM, so remove the AFM first. -Mark]

8. Remove the front engine cover to access the timing and balance shaft belts (The cover is two pieces and is attached by 10mm head bolts).

9. Remove the crankshaft pulley bolt using a 24mm or 15/16" deep socket. [Easier said than done. I needed a 4’ cheater bar on a ½” drive 24mm deep impact socket to break this bugger. -Mark] Remove the power steering pulley.

10. Loosen the balance shaft belt tensioner sprocket lock nut, then turn the tensioner nut counterclockwise to release the tension on the balance shaft belt.

11. Loosen the balance belt idler idler roller lock nut, then rotate the idler to provide clearance for removal of the balance shaft belt.

12. Remove the balance shaft belt and mark the direction of rotation on the belt if it is to be reused. Remove the alternator/AC pulley and balance belt gear as a unit from the crankshaft. [Removing the alternator/AC pulley can be hard. Note that “wiggle” method works. Also, I’ve put this step in correct sequence—after the balance belt has been removed. -Mark]

13. If the balance shaft belt idler and balance shaft tensioning roller are to be inspected or need to be removed for other maintenance (i.e. water pump or oil seals), remove the locknuts and slide the rollers off the shafts.

14. If the balance shaft sprockets need to be removed (i.e. water pump or oil seals), the sprockets will have to be locked in place to allow the retaining nuts to be loosened. Use the Balance Shaft Pin Spanner to hold the sprocket while loosening the retaining nut. You can also use two large punches and a set of locking pliers to hold the sprocket, but this is very awkward. [Don’t even think about it – get the tool. You’ll also use it for the autotensioner. -Mark]

15. After the retaining bolts have been removed, slide the balance shaft sprockets straight off the shaft. You may need to slide a small pry bar behind the sprocket to get it started.

16. Using IGN-01, remove the distributor cap and the aluminum cover behind the distributor cap. This will reveal the main camshaft sprocket.

17. If the timing belt is to be reused, mark the belt for direction of rotation before removing it.

18. On cars not equipped with spring tensioners (pre-'87), perform the following: [Ignore step 18 (deleted), it doesn’t apply to S2. Refer step 19 instead. -Mark]

19. On cars equipped with spring tensioners (87 Model Onward), perform the following:
a. The front plate of the spring tensioner resembles a triangle. Loosen, but do not remove, the locknut and bolt on the side of the triangle near the tensioning spring.
b. Remove the tension on the belt by pushing down on the tensioner lever arm. This can also be done using the factory balance shaft spanner if you have one. With the spring still compressed, tighten the locking bolt and nut. This will allow you to install the new belt without having to fight the spring tensioner.
c. To remove the timing belt, the spring tensioner must be removed. Remove the entire spring tensioner assembly as a unit. The three bolts on the face plate of the spring tensioner are not used to remove the unit. There are three bolts (which are very difficult to see) at the back of the tensioner near the block which must be removed to get the assembly out. [Note: These are three recessed 13mm nuts, two on the vertical right side of the tensioner (looking from the front) which can be found by feel without too much difficulty. The third nut is a bugger to find, and – crucially -- the timing belt idler that bolts on to the autotensioner unit _must_ be removed first to get a socket onto it. The third nut is positioned at the bottom of the idler, at about the 5 o’clock position (looking at it from the front). -Mark]
d. Remove the timing belt, being careful not to twist the belt if it is to be reused.

NOTE

On spring tensioner cars, I find it very difficult to remove and install the timing belt with the spring tensioner assembly in place. [Actually, it is not very difficult, it is impossible, at least on the S2 – the autotensioner needs to come off if the belt is to be removed – it simply won’t fit behind the tensioner gear. -Mark] I prefer to remove the spring tensioner assembly from the car during belt removal and reinstall while timing belt is being routed during installation.

20. If the camshaft belt idler is to be inspected or removed for other maintenance (i.e. water pump or oil seals), remove the retaining bolt and the camshaft belt idler. [It will already be off if the autotensioner has been removed -- see 19 c above. -Mark]

21. The back timing cover can now be removed by removing the 10mm bolts holding it in place. The back timing cover must be removed when replacing the water pump, front crankshaft oil seal, and the balance shaft oil seals. [Put this step in correct sequence for S2. -Mark]

22. If the crankshaft gear needs to be removed (i.e. water pump or oil seals), a gear puller is the easiest method. However, if a gear puller is not available, you can slide a pry bar behind the gear to get it started. [Overnight soaking in penetrating oil (like PB Blaster) has also been recommended. Penetrating oil worked well for me, in conjunction with a large screwdriver to” wiggle” the gear off the shaft. Without the penetrating oil (it worked very quickly – about 10 minutes) it was unclear the wiggling would work at all. -Mark]

23. If an S2 owner is removing the crankshaft gear, it is presumably because the crankshaft seal needs attention. In this case, the woodruff key needs to be removed as the next step. This can be done in the standard way using cutting pliers to grasp the key and ease it out. This is not easy, and takes some patience. I believe the penetrating oil in my case made it come out more easily after some wiggling and light tapping on each side with a large screwdriver and hammer. -Mark

24. The large washer behind the crankshaft gear is free to come off the shaft after the woodruff key is out, and removing this exposes the seal and oil pump sleeve. The oil pump sleeve has an inner o-ring that needs to be removed by prying it with a sharp pick tool of some description – I used the sharp tip of a spade bit to get it started down the shaft. After this has been removed, the oil pump sleeve can be removed by gently grasping the 1-2mm end that is exposed with a set of grips or similar. It is simply a case of gently pulling it, being careful not to mark the surface by grasping too hard with the jaws of the grips. Once out, finally the front crankshaft seal can be removed. -Mark

Clark's Garage © 1998

Luis de Prat

Mark, you read my mind.

KuHL 951

I suppose this works on the 87-88 944S also since they talk about 87+ and turbos also.

Luis de Prat

Are you referring to tensioning with the spring tensioner?

So, if I'm just changing out the belts and not replacing any of the front engine seals (were replaced less than 50K miles ago at 124K), I take it the crankshaft pulley doesn't need to come off? Just feed the belt through the spring tensioner?

Mark944na86

It doesn't _need_ to come off, strictly speaking, but Clark warns that getting the timing belt on with the balance gear still on the crankshaft is "extremely difficult". If Clark says "extremely difficult", I'd worry.

If I were you, since you've got the flywheel lock, I'd try to get the crankshaft gears off first, and only try to do it without taking them off if you run into difficulties. You can leave the timing belt gear in place on the crankshaft; you only have to remove the PS pulley, and then the alt belt pulley/balance gear (as one unit).

Luis de Prat

Then I'm happy to remove the crankshaft gear. But this doesn't involve removing the crankshaft bolt that takes a monstrous amount of torque and you used a 4' cheater bar on, right?

Mark944na86

It certainly does require removing the crankshaft bolt. But the key is that you need the appropriate tool. It was easy with the 4' cheater bar, but impossible (for me) with the 18" ratchet I started with (but didn't end with -- I actually broke it!). I had to just keep upping the ante until I discovered what "appropriate" was in my case. Think "Archimedes".

BTW, putting the bolt back _on_ with 155ftlb of torque was easy -- I was surprised how quickly I got to 155ftlbs with an 18" torque wrench. It was getting it _off_ that was difficult. I don't know what torque I was applying to break it, but it was a lot more than 155ftlbs going back the other way.

Luis de Prat

OK, so I'll get a 4' length of steel pipe to fit over my 1/2" breaker bar... Thanks!

KuHL 951

I'm still trying to figure out why the crank pulley has to come off to install a timing belt on cars with a spring tensioner? Is there a different PS pulley assembly or tighter clearances with the belt cover on the 87+ cars? I've always been able to slip the timing belt behind the pulley on my 86 and earlier cars. I just slip the belt in on edge, flip the belt, and pull both sides snug to make sure it seats correctly on the TB sprocket. I've never had to remove the crank bolt or use a flywheel lock yet. I can see removing the tensioner but I must be missing something here about that crank bolt.

Mark944na86

Not having tried it with the balance gear in place, I can't say. The basis of the above comment is this note from Clark:

Perhaps someone else can chime in to explain the difficulty (if there is one.)

Barry Lenoble

Hello,

I have done many (too many to remember) timing belt jobs, and I have NEVER removed the crank pulley.

I do remove the auto tensioner device.

To install the new timing belt you need to sort of fish it behind the balance gear, give a little tug here and there and otherwise work it. It may take 10-15 minutes. That is a whole lot less than removing the crank pulley.

I don't bother with the fly wheel lock either. Rotate the engine to TDC, put it in gear, and change away.

Of course, you are going to double check everything before you start the engine, right?

Good luck,
Barry

catbug12

I've been thingking about doing mine also, but what I worry about is how to get the belt tension right.Is there any way to do it without getting that $500 tool?

Mark944na86

Yes, several options that have been discussed here many times, but since search apparently isn't working as well as it should be:

1) If you have an autotensioner (87 models and later), you can, in theory at least, just rely on that to get the tension right, without needing any other tool to verify tension. In practice, many people feel uncomfortable without some backup measuring tool, but at least a few rennlisters have reported that they are happy to simply let their autotensioners do the job they were intended to do.

2) The original "twist" test. Original, because before the P9201 tool became available, that's what the Porsche factory recommended. Many experienced techs still rely on it, apparently.

3) The "krikit" V-belt tension measurement tool. Cheap, simple yet effective according to many who reported success using this tool. Check eBay.

4) The ArnnWork P920X tool - a more expensive tool (more expensive than the "krikit", that is) purpose built for the job by Bruce Arnn (F18rep on this forum), but still much less expensive than the Porsche special tool. Check www.arnnworx.com.

There is also the "optibelt" sold by 944ecology which looks in the pictures to be very similar, if not identical, to the "krikit" tool.

So take your pick!

Mark944na86

Well, there you go, Luis -- maybe try to install the belt without removing the crankshaft gears first, and only resort to that if you get into difficulty.

Clarks-garage is a great resource, but the advice is not necessarily the last word on the subject!

And if you have success (or not), we can modify the annotated instructions above based on your experience.

Riff

As for having to remove the balance belt gear, I have had to do it when changing the belt on my S2. I think it has to do with the width of the belt. On the S2, the timing belt width was changed to a wider spec. The gap between the balance belt gear and the belt covers is pretty tight and making the belt wider did not make matters easier. Could one slide it in there without removing the gear, probably, but it is not easy. It is easier (for me) to just remove the crank bolt and no, I do not have airtools to make the job easier.

Good luck with your TB job Luis!