jstand22

I used the auto-tensioner on my car and it tensioned the belt correctly. I did use the krickit to confirm, and you can make adjustments.

968PORSCHE

Unfortunately you need to replace all that crap on the front of the engine that you can. I think that covers it! Ok more detail. Replace all the seals, crank balance shaft etc. Also on my 968 there are little metal colars on the balance shafts that need replacing as well. The water pump is an integral part of the cam drive system and absolutely needs to be replaced! By the time you replace all the rollers, you have spent some real money, but you will be rewarded with a good running car that probably will not leak. You can also be confident that valves will stay away from pistons!

968PORSCHE

I've used a place called BMA in Burbank, CA they do internet sales have good prices and use OEM parts. I'm sure they can get the kit, or put one together for this car.

944S2IFISH2

Did anyone notice in the TB posted earlier that it doesn't say to roll-back the engine at all (1.5 cam teeth, x degrees)? I recall that the FSM and clarkes say to do that, and it definitely affects the belt tension reading (Slackens the belt). Any experts have the scoop on this? Thanks...

Mark944na86

Is there a resource that describes the timing belt tensioning procedure just using the spring tensioner? In particular, what tools are needed? Presumably, you can dispense with the thin wrench, the 9201 (or equivalent), but still need a flywheel lock? Any other special tools required for this method?

Riff

As noted by jstand22, that is the procedure, use the spring tensioner to set the load, then confirm with the Krikit. Just make sure you lock out the tensioner before taking any readings with the Krikit.

You can make do without a thin wrench, but I have found that for the S2, a collet wrench for a router is the same size as needed. The flywheel lock is a must, just because you need it to hold the crank when applying the 150ft-lbs to the crank pulley.

Mark944na86

Forgive me if this is a possibly stupid question, but what if the spring tensioner is a bit out according to the 9201 (or 920X or kriket), and you want fine tune the tension manually?

Looking at the diagram, it's not obvious to me how you do this. Looks like it's the spring or nothing -- what do grab hold of to do a manual override?

Riff

Not stupid at all. The spring arm moves against the belt until the tension in the belt is equal to the spring force; at that point you lock the arm down and fix the point of the roller. Take a reading and decide if it is good or needs adjustment. If the belt requires more tension, then you loosen the lock down bolt and apply additional load to the arm to tighten the belt further and again lock it down and take measurements. If the belt is too tight, then you do the converse and just back the arm off a bit and again lock it down and take readings.

When doing this I would just push against the roller increase/decrease the load.

Good Luck!

Mark944na86

OK, thanks guys for all the insights and pointers; I now feel like I've got enough info to formulate a plan.

So, looking closely at the service records, I've decided to just do the belts, rollers and seals (except maybe the cam seals, as Bruce Arnn says on his site that removing the cam gear is a pain, and it rarely leaks from there anyway.)

The water pump was replaced 56000 kms ago (about 35000 miles), the timing chain 34000 kms ago (about 21000 miles). So I suspect they've still got some life in them yet.

The rollers, apart from one of the balance shaft rollers, may never have been replaced since new (173000 kms, or 108000 miles). Hard to believe, as the records show the belts being replaced at the correct intervals, but since the rollers don't get mentioned (except for that one time) in the fairly detailed records, I feel I have to assume they are long overdue.

For tools I've bought the flywheel lock, the pin wrench, the 27mm thin wrench (all Arnworx tools), and a kriket-1.

The only outstanding issue at this stage is what are the correct belt tensions: Clark's garage and Bruce Arnn don't seem to agree. Here's a summary of what they say:
Arnn's unit are described as lbs, and Clark's garage don't specify what their units are (I assume 4.0 is 40 Lbs).

Which site is more uptodate with respect to the Porsche factory recommended specs?

Mark944na86

*bump*

So anyone got any ideas about the correct belt tensions?

Riff

When I do my belts with the Krikit, I use 40 for the cam belt and 28 for the balance belt.

Some more good info on how to use the Krikit is here:

Marcus Blaszak Webpage

Mark944na86

Riff,

Thanks for that -- looks like you're in broad agreement with Marcus Blaszak and Bruce Arnn on this.

(That Optibelt tool looks _very_ similar to the Kriket, doesn't it?)

What value do you use when retensioning the T-belt? Arnn's 37.5 or Clark's 27.5? (Seems like a big difference!)

Also, I assume the B-belt is simply retensioned to 28 if it has streched at all after 4000 miles (or so.)

-Mark

F18Rep

Morning sport fans... You are correct sir. I have tried this many times and eventhough a few have reported being to able use the krikit on a spring tensioner equipped engine; I have never been able to get it to work. If someone can elaborate on exactly how to use it, I will run a little test and see if it works against factory tool. In the past though, I've tried to find a place along the belt spans to place the krikit. But every place I've tried gets a reading that I thought was bogus because I'm deflecting the belt into contact with some piece of engine hardware. Maybe the tension value is 'good enough' that is your call but it did not look kosher to me. The non-spring tensioner cars do not have this problem because they have more room to deflect the belt.
Bruce
PS.. I love the idea of the krikit but I think it is little like trying to read a millimeter with a yardstick.
PSS.. the Clark reference (4.0) is using the factory tool, different measurement system than the krikit. Theoretically the two values represent similar belt tensions though.

Luis de Prat

I need to do this on the S2 as well. Any caveats or tips besides pulling out the fans? Wish there was a comprehensive DIY with pics somewhere...

Mark944na86

Thanks for replying Bruce, but I don't see how they can be reconciled even theoretically.

Suppose 4.0 = 40 lb (timing new)
Suppose 2.7 = 37 lb (timing used)

But also

3.5 = 27.5 lb (bal new style)

This would mean that 2.7 on the 9401 corresponds a higher tension (37 lb)
than a reading of 3.5 (27.5 lb)

This is just silly, of course.

Further, you will notice that the recommended values on clark's site (which were taken from a version of the wsm originally, I'm not sure what date) suggest a used timing belt should have _less_ tension than a new style balance belt, whereas the values published on your web site suggest the a used timing belt should have significantly _more_ tension than a new style balance belt.

To quote Elmer Fudd "somethin' scwewy goin' on..."

-Mark