Charlie944

Hello all, I am putting the 84' back together and I am getting the
following in regards to the T-belt tension. Using the Kricket-1 at
the midpoint between cam and crank while dialed back 1.5 teeth on the Cam the KR-1 is showing 38lbs. I am testing it on the top or flat side of the belt. The belt is also hitting the water pump pulley when I push down
on the Kricket...which I feel is altering my readings. I set it initially at ~90deg twist, locked nut, then rotated engine 270deg CW at the crank (1 rev at Cam) and checked again, and I came up with 38-39lbs. Question: is the belt suppose to touch the water pump pulley? Personally, I can twist it about 110deg at the midpoint when dialed back. And by looking at the tensioner eccentric I am about out of adjustment! The belts are Contitech with 944 part #'s and I installed all new rollers and water pump.

Did Porsche when designing our engines incorporate just a certain amount of adjustability...so as to prevent someone over tensioning, or tweaking their belts a little further instead of replacing them??? In other words: is the 4.0 +-.3 or the 40lbs (Kricket) the MAX our T-belts will tension to when using the latter tension procedure??? All of which was followed to the 'T' from Clarks Garage, and all the insightful post by all of you generous folks.

Also just to share, when I had my belts done last time by a very reputable high-end auto shop (always has some Porsche, Mercedes, Jag, Saab there) that utilizes the P9201 tool...my belts whined quite noticably...I never had a problem resulting from the forementioned whine. And even when I had a Bal.Shaft Adj...it came back with a whine...not as severe as with both belts fresh though. I am curious what I will end up with my doing the procedure.

Any help or advice is surely appreciated..TIA!!

RSflared72e

At the risk of starting this debate again...my experience has been that if the belts whine, they may be too tight (if even just a little too tight). I used to think the whine was normal but experimentation with my 9210 tool on my own cars has convinced me otherwise. The whine will usually be coming from the balance shafts and/or the water pump. Remove the balance shaft belt and run it that way for a moment to diagnose.

I think a lot of shops tension on the tight side with the assumption that the belts will loosen, and that the average owner ain't gonna be back for a long while...

I have the UPP balance shaft delete kit and Broadfoot AC delete kit on mine so only 2 total belts to worry about!

YMMV Al

SoCal Driver

If you have the metal fence that goes on the water pump I suggest you put it on. This seperates the timing belt teeth. A loose belt slaps and hits itself coming and going shearing off teeth.

Charlie944

Thanks guys...yep I have the metal belt guard for the updated water pump, and I cut my rear timing cover to your specifications SoCal....I appreciate the graphic!! Everything is all buttoned up and I am ready to set tension on the Alt and PS belts.

Take Care!

joseph mitro

just did this job monday. the alternator belt was previously tensioned to 50 lbs by the shop - i couldn't find any other reference - and that's what i kept it at. the p/s belt is tensioned until you only have 5mm of deflection

Charlie944

Thanks Joseph! I did a search on the Alt belt tension yesterday, where Skip chimmed in on and he stated that the Alt/AC belt was to be tensioned to 85lbs....I used my Kricket, (I did the 90deg twist method too and I could twist it no further than 90deg) and 5mm diflection on the PS belt. Iwas going to check in my Haynes manual but it got soaked and of course pg117 (the one I needed) was mushey pulp!
Take Care!

ronin-1

you sure you don't mean 38 to 39 Kg for the KR1? (instead of pounds) 38 lbs would be pretty loose (the top scale is kilos)

Charlie944

Ronin, everything I have read and researched on this board has stated: 40lbs for a new timing belt, 35lbs for a broken in timing belt, and 30lbs for a new balance shaft belt. I set the got the timing belt to 40lbs (I moved the eccentric over all the way to offcenter on the stud) and moved it counterclockwise till 40lbs and the belt does not flop, or vibrate horribly. Plus the belts sound pretty good too.

If you have other information I would be happy to see it.
Take Care!

ronin-1

thanks for the info. that makes sense. re-reading my post, around 40 Kg would be a damned bit tight. unfortunately I don't have a 9201 laying around and that's the only reference the FWSM uses so I'm still getting used to the pound figures. were you able to get consistent readings on your KR1? I haven't used one on the timing belt yet but I'm satisfied with the results I get for doing the others

Charlie944

Ronin, your welcome...I did get consistent results using the Kricket. One thing though that should be done (even though tough given the cramped space) is to keep the Kricket from wabbling or rocking side-to-side. This usually is not an issue with tighter belts such as the alternator belt (85lbs). I am in the process of bleeding the cooling system now. One thing I did find very useful was when positioning the balance shaft was to NOT align them initially, but to set them ONE tooth clockwise. So when you apply tension to the lower balance shaft tensioner the upper and lower sprockets will rotate into their proper aligned position. Thank you all for your replies!