Early SHARK timing belt question
11-30-2003, 03:22 PM
#1
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Early SHARK timing belt question
I've read in the Tech FAQ that when the pre 85 928 timing belts break, that valve damage would not be likely as opposed to the later years. Can anyone confirm this? I'm the 2nd owner of an 83s 5speed. 54k I aquired the car at 53k. Origional owner said the belt had been replaced. What signs do I look for that indicate the indeed it had been replaced. I'm a big believer in preventative maintainance. I guess all shark owners all have to be,right?
11-30-2003, 04:23 PM
#2
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Matt,
I've read that only the 78 - 79 motors were truly non-interference motors. Other have survived belt breaks on 4.7 - liter US motors. Why risk it? It will need to be done sooner or later, make it sooner.
Time as well as mileage should be taken into consideration for when to replace the cam belt. Also, has the water pump replaced? Most agree that 7 years is the max age for a cam belt, 5 years is a safer number.
When in doubt, replace the belt and water pump. Be sure an use NEW bolts when replacing the water pump. Also check all the roller bearings and the cam belt sprockets. Wear on the cam, oil pump and crankshft sprokets reduces the life of the cam belt. Replace worn sprockets.
Your 83 may have the old "square" tooth belt and sprockets. If your sprockets are worn, it would be wise to upgrade to the newer "round tooth" belt and sprockets. If they aren't worn, there is no compelling reason to change belt styles.
I've read that only the 78 - 79 motors were truly non-interference motors. Other have survived belt breaks on 4.7 - liter US motors. Why risk it? It will need to be done sooner or later, make it sooner.
Time as well as mileage should be taken into consideration for when to replace the cam belt. Also, has the water pump replaced? Most agree that 7 years is the max age for a cam belt, 5 years is a safer number.
When in doubt, replace the belt and water pump. Be sure an use NEW bolts when replacing the water pump. Also check all the roller bearings and the cam belt sprockets. Wear on the cam, oil pump and crankshft sprokets reduces the life of the cam belt. Replace worn sprockets.
Your 83 may have the old "square" tooth belt and sprockets. If your sprockets are worn, it would be wise to upgrade to the newer "round tooth" belt and sprockets. If they aren't worn, there is no compelling reason to change belt styles.
11-30-2003, 06:14 PM
#3
Nordschleife Master
This is a common issue with new owners. Without documentation, you don't know and, frankly, you can't tell. The problem is that age is a issue in addition to actual use. So a 6-year old belt might look good but have weakened.
I'd pull the right-side cam cover, just because it's easier, and look at the belt. The main check is for cracking across the belt on top and bottom. Also look for wear on edges. And that the belt looks clean and shiney. Readable printing would be nice.
Check the tension while you're at it.
Depending on that check, I'd move the belt job between immediately and like next Summer or some convenient time.
I'd pull the right-side cam cover, just because it's easier, and look at the belt. The main check is for cracking across the belt on top and bottom. Also look for wear on edges. And that the belt looks clean and shiney. Readable printing would be nice.
Check the tension while you're at it.
Depending on that check, I'd move the belt job between immediately and like next Summer or some convenient time.
11-30-2003, 06:22 PM
#4
Nordschleife Master
The 4.7l US engines will typicaly survive a belt break w/o problems.
I know because it happened to me.
You frankly can't tell if it's bad or not. And even if the belts OK, if a roller freezes up, you've got problems. Trust me.
I know because it happened to me.
You frankly can't tell if it's bad or not. And even if the belts OK, if a roller freezes up, you've got problems. Trust me.
