Visual cues to age of a T-belt
01-20-2018, 07:15 PM
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Visual cues to age of a T-belt
I recently acquired an ‘84 928 with 74000 kms or 46000 miles. The previous owner had purchased it from a dealer, had owned it for three years and only put 5000kms on it. He also had zero maintenance records unfortunately.
My plan is to baseline as much I can- fluids, hoses, fuel lines etc. including the timing belt. My question pertains to to what else I should be doing while attacking the t-belt. Normally I’d do a water pump as good practice while doing a t-belt. After pulling a cover, the Porsche branded belt looks like it may have been changed not many miles ago. The back of the belt exhibits very little wear with all of the writing clear and legible. Am I reading that correctly or making a huge assumption? What would you do? Change out belt, pump, pulleys, etc.? Or just the belt?
My plan is to baseline as much I can- fluids, hoses, fuel lines etc. including the timing belt. My question pertains to to what else I should be doing while attacking the t-belt. Normally I’d do a water pump as good practice while doing a t-belt. After pulling a cover, the Porsche branded belt looks like it may have been changed not many miles ago. The back of the belt exhibits very little wear with all of the writing clear and legible. Am I reading that correctly or making a huge assumption? What would you do? Change out belt, pump, pulleys, etc.? Or just the belt?
01-21-2018, 10:25 AM
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considering the minimal cost of the belt in the grand scheme of things, I would replace it. It is not accurate to determine the health of any belt by simply looking at it. You can determine a that a belt is bad if it looks bad, but the same is not true if it looks good. It could still be bad. Old belts break down, and even though they may look ok, with printing on them intact, etc., they could still fail.Also, to Jim's point, if it is a non-interference motor, then the chance of a torpedoed engine is small, but still, I would not want to go back in and tear it all apart due to something relatively inexpensive that I could have replaced when I had it all apart. My $.02.
01-21-2018, 12:05 PM
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There’s no question that I’ll be changing the belt. My question more pertains to the other components in there. If I can determine that the belt has few miles on it then it’s likely the water pump, etc have few miles as well. Although, It’s not yet reached its first belt service interval according to mileage so perhaps if the belt was changed, the pump was not. I can check bearing play and feel I suppose. For ultimate peace of mind I guess I should just change the pump.
I dont think a North American market ‘84 has an interference engine. But still, getting stuck, getting towed... no thanks
I dont think a North American market ‘84 has an interference engine. But still, getting stuck, getting towed... no thanks
01-21-2018, 12:22 PM
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You seem to have the correct approach. The first potential problem you have with the pump is that you do not know what is there. It could be a good factory spec pump or some other lower grade item that may or may not have plenty of life left in it. If the pump installed has a metal impeller there is always the risk of casing damage if the impeller bearing lets go not to mention the condition of the cam sprockets etc which theoretically with such a low mileage ought to be like new.
My circumstances are of course different having a 32V motor and living in a hot climate- I change my timing belt every 6 years or so irrespective of mileage and change out the pump if and when it exceeds 60k miles.
Even though most of the 16V motors are non interference I would not want my timing belt to go twang so provenance of the system is paramount [sacrosanct?].
My circumstances are of course different having a 32V motor and living in a hot climate- I change my timing belt every 6 years or so irrespective of mileage and change out the pump if and when it exceeds 60k miles.
Even though most of the 16V motors are non interference I would not want my timing belt to go twang so provenance of the system is paramount [sacrosanct?].
01-21-2018, 12:32 PM
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01-21-2018, 12:46 PM
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A timing belt can 'tell you' if it is bad and needs to be replaced. However, visual inspection cannot tell you if it is most-definitely good. In my 'story-telling' collection of old timing belts, the visually best-looking belt is the one that went 44k-miles and 17 years after being installed on the assembly line. The worst is a belt that had "been replaced 1500 miles" before I went in after it.
01-21-2018, 12:46 PM
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I think I’ll strip it down and have a good look at what I’ve got and decide from there. Really leaning towards changing the pump and belt. I’ll probably sell this car in the near future so it would be good to pass on a known quantity to the next owner.
01-22-2018, 01:45 AM
#10
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I recently acquired an ‘84 928 with 74000 kms or 46000 miles. The previous owner had purchased it from a dealer, had owned it for three years and only put 5000kms on it. He also had zero maintenance records unfortunately.
My plan is to baseline as much I can- fluids, hoses, fuel lines etc. including the timing belt. My question pertains to to what else I should be doing while attacking the t-belt. Normally I’d do a water pump as good practice while doing a t-belt. After pulling a cover, the Porsche branded belt looks like it may have been changed not many miles ago. The back of the belt exhibits very little wear with all of the writing clear and legible. Am I reading that correctly or making a huge assumption? What would you do? Change out belt, pump, pulleys, etc.? Or just the belt?
My plan is to baseline as much I can- fluids, hoses, fuel lines etc. including the timing belt. My question pertains to to what else I should be doing while attacking the t-belt. Normally I’d do a water pump as good practice while doing a t-belt. After pulling a cover, the Porsche branded belt looks like it may have been changed not many miles ago. The back of the belt exhibits very little wear with all of the writing clear and legible. Am I reading that correctly or making a huge assumption? What would you do? Change out belt, pump, pulleys, etc.? Or just the belt?
Given that you have a non-interference engine with the later (stronger) cam belt design, you can safely forget changing that belt.
Inspect the pieces, replace any worn pieces, make sure the tensioner doesn't leak, retention that belt, bleed the tensioner, and save that $100 for something else.