It always made me worry that it can snap toward the end of its service life or just simply cost me more time in repairs due to the short interval.
I took a gamble that paid off because of something I had read on the brickboard a couple of years ago.
I ordered a set of '94 960 timing set; basically the TB 252 belt that's used in all 20 valve 850s after '93-'94 after engine serial number 131034, the larger idler pulley, the larger tensioner and the slightly deeper hydraulic tensioner.
Parts required:
TB 252 timing belt 23mm X 148 teeth (OE 271856)
9135033 hydraulic tensioner
9135036 timing belt tensioner pulley
9146376 timing belt idler pulley
longer 40mm thread size hydraulic tensioner bolts 8mm X 1.25mm from later model 850 or 960 X 2
longer 55-60mm M10 X 1.5mm tensioner pulley bolt with unthreaded 35mm shoulder from bolt/engineering supplier
A used timing belt and vice grips
A drill press
A 30mm hole saw for timing cover
A 10.2mm drill bit
First thing to do is remove the T45 bolt from the timing belt tensioner pulley as you can't use it on your motor. Use a vice grip to hold the rear washer and turn the T45 until it screws off the washer.
Then remove the pulley sleeve as this needs to be drilled out to 10.2mm diameter.
Grip the pulley sleeve with a used cut timing belt to avoid damaging it and place it with the large end on your drill press base.
Make one pass while using cutting oil to prevent damage to the drill bit (get someone to spray the oil while lowering the drill)
You should end up with a very neat hole of approximately 10.25-10.40mm. (mine was 10.33mm) This gives the bolt the required 0.4-0.6mm of play from the M10 bolt sides. Drill the rear washer out as well. Remove any burrs with a file. Thoroughly clean the sleeve as its inner & outer surfaces must be totally clean.
Now insert the M10 bolt through the newly drilled sleeve through the timing belt tensioner pulley and place the newly drilled washer behind it. You will now need to mark & drill your timing cover as the new bolt will prevent it from fitting. I used a 30mm hole saw and it looks neat and tidy.
The beauty of this mod is that the newly drilled sleeve can be re-used on your next timing belt tensioner pulley.
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