acfurla
Active Member
Posts:61
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| 08/22/2008 12:42 PM |
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Just a reminder for you "water cooler" fans. Please remember to keep a strict maintenance schedule for your cam/balance shaft belts, rollers, and front seals. If the Timing Belt snaps...that will mean at the very least a new set of valves...a "top-end" rebuild...or the entire motor. The loss of the Balance Shaft belt is not a "Code Red" situation though. For those who don't log the 40-45,000 miles...then use a maximum 4 year interval. I will attach some information sourced from "Clark's Garage"
5.6.1 Timing Belt
For the 924S, 944, and 968 series cars, it's important to have both the cam timing and the balance shaft belts replaced and tensioned regularly. These models, as well as later 928 models, have what is know as an "interference engine." If the timing belt fails, pistons and valves will travel out of sequence with one another. The result of this is .that pistons and valves will collide, valves will be bent, and you are then in for a very expensive repair
Tensioning the timing belt requires an expensive special Porsche tension gauge, the P9201, that costs about $500. A few hardy owners use the more traditional "by hand" method generally without any adverse affects. However, the general consensus is "better safe than sorry" -- use the factory tensioning gauge.
1987 and later 944's have an automatic tensioning device built in that in theory allows you to perform this operation without the special gauge. However, the automatic tensioner has been known to produce incorrect settings. Moreover, Porsche found that the 944S2 suffered from cam timing belt slap when tensioned with only the automatic tensioner. The bottom line is that the P9201 tool should still be used on the 87 and later cars with the automatic tensioner
The belts should be changed at least every 45K. If a car your are considering for purchase does not have service records indicating that this has been done, allow for an extra $300-$500 to have the belts changed.
The timing belt in a 924 is reported to be far less finicky than the 944 or 924S. Since the 2.0 engine does not have an interference design where the pistons and valves share space, a failure of the timing belt does not produce the kind of expensive collataral damage as in the case of the 944 or the 924S, viz. a piston hitting the open valves, necessitating an expensive engine rebuild. While the maintenance interval for the 924 timing belt is the same, the expensive tensioning tool is not needed.
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Alex
'83 944, Zermatt Silver/Black Leather, 5-Speed, Factory Stock, Original Owner |
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