p_tothe_g

Hey all,

Recently replaced waterpump on '89 S2. I put in a new timing belt/balance shaft belts about 7,000 miles ago with new idlers and rollers. After putting her all back together and firing it up after replacing the water pump, I have a belt slap noise coming from the timing belt area, not so noticable at idle, but much more so right off idle to around 2k-3k rpm. This is my 3rd time putting a timing set on a 944, 2nd go around on this S2. The belts are 7k miles old and everything was tensioned and put in place per 'Clarks' instructions. even got my hands on the Porsche tensioning gauge. I have tripple checked belt tension and they are right on the spot. Have checked calibration in the gauge and it is OK too. Belts feel tight, not loose. No marks on the belts after running about 150 miles of light duty cruising. Timing cover is in great condition and back cover is fastened to the block correctly. If anything, the balance shaft belt sems to run a little close to the water pump pulley, real close. but other than that, noting appears or measures out of spec.

Any ideas???

Luis de Prat

Hi. Did you set the balance belt idler to spec at 1mm clearance from the belt?

p_tothe_g

Yeah, set it with feeler gauge to 1mm, just like I have in the past. I know the balance shaft belt seems to be riding a bit close, but my hunch is the timing belt. Just was out in the garage and loosend the tensioner and retensioned the timing belt, have a reading of 2.4 on the guage prior to loosening it (and I even rotated the engine counter clock by 1.5 cam teeth). Funy thing is, I had it set to 2.9 2 days ago!!! Think I may have stripped the tensioner lock nut shaft (the one set into the tensioner) and even possibly the adjusting bolt!! They both hit torque of 33 ft-lbs (45 nm) but I don't dare go tighter. Mybe the belt is still too "Fresh" to be tensioned at the lower "used" level of 2.7 on the guage? And I should probably get a new tensioner

Yabo

Are you sure it is belt slap noise? can you see it slapping if you run it without belt covers on?

Tom M'Guinn

Do you have the little calibration bar for the gauge -- that will tell you if it is still calibrated correctly, and if not you can reset it with a tiny alan key. Were you mindful of turning the tensioner in the correct direction? If you turn it the wrong way, you can get the belt to the right tension, but the tensioner cog (and belt) will run too close to the cover.

p_tothe_g

Yes, I do have the calibration bar and it reads 4.0 on the spot when the bar is installed. The S2 has a spring tensioner for the timing belt and the eccentric for the balance belt. the spring tensioner only goes in one direction to tension, but just like clark's says, you need to give it a nudge to get the proper tension. The lock nut and the bolt that holds the position do not seem to be hitting torque now, and both apear to be stripped in the tensioner body.

I have the balance shaft tensioner set in a counter-clockwise manner as written in most instructions. If it is tensioned clockwise, the balance shaft idler has to be at its minimum setting to not interfer with the belt, so I think counter clockwise is the way to go for that, but I am open to any clarification on that one!

Pretty sure my timing belt tensioner is loosing its grip, need to take it out and see if I cant re-tap the holes or put an insert in both locations, otherwise, need to get a new one before further diagnosis can be had