Timing belt, fact or Internet folklore?
09-21-2015, 11:01 AM
#61
09-21-2015, 11:26 AM
#62
Rainman
Rennlist Member
Rennlist Member
It's been said here it's a big 4 cylinder engine is hard on belts. Chrysler's 2.5L with a Turbo makes 150HP. It's been said here it's the power pluses of a 4 cylinder engine. Fiat and VW both had 4 cylinder diesel engines. Most 4 cylinder engine's the timing belt also drive's the oil pump. The 944 is the only car that l know of that the oil pump is driven off the crankshaft.
I wonder how much of the timing belt terror was caused before the introduction of the metal belt guard that bolts onto the water pump. Imagine having your belt go a little loose and then teeth going one way catch the teeth going the other way as they pass the pump...that can't be pretty.
Those should have mostly been rectified by the end of the 1980s though.
09-21-2015, 11:33 AM
#63
09-21-2015, 02:34 PM
#64
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How many other cars had aluminum blocks/heads and a timing belt with no active tensioner? I think this is the major issue, the aluminum grows quite a bit more than an iron engine and the belt has to take all of this up. If it is not tensioned properly it will shorten the life.
There was an anecdote about the early cars having been built with a bad batch of belts leading to the bad rep...
There was an anecdote about the early cars having been built with a bad batch of belts leading to the bad rep...
09-21-2015, 03:25 PM
#65
My experience with my inaugural timing belt change would dictated be ready to fix everything the careless PO you bought it from sold you.
https://rennlist.com/forums/924-931-...has-begun.html
Don't worry, by the time your done you'll know how to fix most everything.
You will also change timing belts or whatever whenever you feel like it.
https://rennlist.com/forums/924-931-...has-begun.html
Don't worry, by the time your done you'll know how to fix most everything.
You will also change timing belts or whatever whenever you feel like it.
09-21-2015, 06:04 PM
#66
Rainman
Rennlist Member
Rennlist Member
Timely but unfortunate - this guy went 4 years on a belt.
https://rennlist.com/forums/944-turb...ming-belt.html
https://rennlist.com/forums/944-turb...ming-belt.html
09-21-2015, 07:16 PM
#69
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i don't believe the 4 years is too long mantra.
no way. that's getting close to silly. i've also heard 3 years quoted on these forums for years. that's full on nuts.
no car's inherent design can be THAT UTTERLY WORTHLESS. not even a 944.
if you can wrench, and it makes you feel good.... you have carte blanch.
the first owner of my '87 944S and me put 116k miles on a set of gen 1 belts over about 8 years
(i purchased the car in 1989 with 17 k miles w/ the original belts).
62k on another (on my 968) on long-life Gates belts. the belts came out of the car pristine.
then again, EVERYTHING was done when they went on.... new bearings/nothing dragging.
guess what, when they came off the car, the bearings were all tired. they were done (MEXICO BABY).
56k on still another (968) set of Gate's belts. Gates belts are designed for long life. they work as advertised.
4 years and low~moderate miles? bullsh t.
6, 7, 8 years? maybe. rotating parts? yes, the plastic gets brittle. 5 years is probably time.
outside of that, if the sh t is seriously, that bad, that belts break in 4 years, then the engine is a bullsh t failed design.
i don't believe the 944 engine is a failed design.
but i do believe it's a highly flawed design.
run Gates belts, along with NEW EVERYTHING for crying out loud - and retension them @ ~1500~2000 miles or whatever...
and you should be fine.
EXPENSIVE? yes. welcome to Porsche. (they planned it that way so the dealers wouldn't scream about lost 911 sales).
it's a flawed design. but not a lemon.
once and for all - it's not the Goddamned belts. ITS GOING CHEAP ON THE OTHER CRAP.
that includes rebuilt pumps. don't do that.
GO AHEAD, BE CHEAP. YOU'LL PAY LATER.
no way. that's getting close to silly. i've also heard 3 years quoted on these forums for years. that's full on nuts.
no car's inherent design can be THAT UTTERLY WORTHLESS. not even a 944.
if you can wrench, and it makes you feel good.... you have carte blanch.
the first owner of my '87 944S and me put 116k miles on a set of gen 1 belts over about 8 years
(i purchased the car in 1989 with 17 k miles w/ the original belts).
62k on another (on my 968) on long-life Gates belts. the belts came out of the car pristine.
then again, EVERYTHING was done when they went on.... new bearings/nothing dragging.
guess what, when they came off the car, the bearings were all tired. they were done (MEXICO BABY).
56k on still another (968) set of Gate's belts. Gates belts are designed for long life. they work as advertised.
4 years and low~moderate miles? bullsh t.
6, 7, 8 years? maybe. rotating parts? yes, the plastic gets brittle. 5 years is probably time.
outside of that, if the sh t is seriously, that bad, that belts break in 4 years, then the engine is a bullsh t failed design.
i don't believe the 944 engine is a failed design.
but i do believe it's a highly flawed design.
run Gates belts, along with NEW EVERYTHING for crying out loud - and retension them @ ~1500~2000 miles or whatever...
and you should be fine.
EXPENSIVE? yes. welcome to Porsche. (they planned it that way so the dealers wouldn't scream about lost 911 sales).
it's a flawed design. but not a lemon.
once and for all - it's not the Goddamned belts. ITS GOING CHEAP ON THE OTHER CRAP.
that includes rebuilt pumps. don't do that.
GO AHEAD, BE CHEAP. YOU'LL PAY LATER.
Last edited by odurandina; 09-21-2015 at 09:00 PM.
09-21-2015, 07:51 PM
#70
Three Wheelin'
OK, l didn't want to dredge this up but thinking about this. l think l may have a answer. First a few things that helped me come to this conclusion.
It's been said here the timing belt is a new technology in 83. My earliest recollection of a timing belt used was the 1966 Pontiac OHC 6 cylinder. It's been said here it's a big 4 cylinder engine is hard on belts. Chrysler's 2.5L with a Turbo makes 150HP. It's been said here it's the power pluses of a 4 cylinder engine. Fiat and VW both had 4 cylinder diesel engines. Most 4 cylinder engine's the timing belt also drive's the oil pump. The 944 is the only car that l know of that the oil pump is driven off the crankshaft.
So what's my conclusion, as Dr. House says, everybody lies. I bet you a lot of those belt failure's the belt was never change. I also believe a lot of diy's (and professional mechanics too) have know idea how tight a belt should be or know a good roller form bad one. Yes some may have bad luck, but I just can't see how the 944 timing belt arrangement being problematic.
It's been said here the timing belt is a new technology in 83. My earliest recollection of a timing belt used was the 1966 Pontiac OHC 6 cylinder. It's been said here it's a big 4 cylinder engine is hard on belts. Chrysler's 2.5L with a Turbo makes 150HP. It's been said here it's the power pluses of a 4 cylinder engine. Fiat and VW both had 4 cylinder diesel engines. Most 4 cylinder engine's the timing belt also drive's the oil pump. The 944 is the only car that l know of that the oil pump is driven off the crankshaft.
So what's my conclusion, as Dr. House says, everybody lies. I bet you a lot of those belt failure's the belt was never change. I also believe a lot of diy's (and professional mechanics too) have know idea how tight a belt should be or know a good roller form bad one. Yes some may have bad luck, but I just can't see how the 944 timing belt arrangement being problematic.
Good info on diesel pulses here: http://www.lovejoy-inc.com/content.aspx?id=600
http://www.ulpower.com/engines/faq/why-no-diesel
Asphalt/bitumen roads deteriorate quicker when they're NOT driven on, than when they are. Could timing belts be the same?
https://en.wikipedia.org/wiki/Crocodile_cracking
http://www.lambertpaving.com/articles.htm
Cheers,
Mike
09-21-2015, 07:51 PM
#71
Rainman
Rennlist Member
Rennlist Member
Rebuilt pumps for a long time were a safer bet than the "new" ones.
Only recently have new pumps been of decent quality.
As for belt life, I changed mine earlier this year at exactly 3 years and they were not far from failing in my opinion, looking over the condition of the belt. It was a Gates brand if I recall, last done in 3/2012.
Only recently have new pumps been of decent quality.
As for belt life, I changed mine earlier this year at exactly 3 years and they were not far from failing in my opinion, looking over the condition of the belt. It was a Gates brand if I recall, last done in 3/2012.
09-21-2015, 09:03 PM
#73
Nordschleife Master
Gotta love the internet! Some people can exaggerate the timing belt situation on 944's. I have owned 944's for a little over 16 years and have never had a issue with a timing belt. I think the key is to change it when its due -- I believe Porsche specs every 3 or 4 years. Personally, I go every 8-10 years or 35k miles (never meet mileage) which ever is first and haven't had any problems. I don't track my car either and its not a daily driver so take that into consideration. If you track the car, I would definitely go with a more rigorous belt change interval.
I just bought a 86' Turbo and the timing belt was changed 10 years ago but only had 15k miles on it. The belt out of that car was just starting to show signs of age but probably could have gone another couple of years with no problems. As other people have said belt technology has come a long way but 10 years is getting past my comfort level.
I just bought a 86' Turbo and the timing belt was changed 10 years ago but only had 15k miles on it. The belt out of that car was just starting to show signs of age but probably could have gone another couple of years with no problems. As other people have said belt technology has come a long way but 10 years is getting past my comfort level.
09-21-2015, 09:10 PM
#74
Drifting
How many other cars had aluminum blocks/heads and a timing belt with no active tensioner? I think this is the major issue, the aluminum grows quite a bit more than an iron engine and the belt has to take all of this up. If it is not tensioned properly it will shorten the life.
09-22-2015, 10:16 AM
#75
Rennlist Member
Surprisingly, no one has mentioned one of the biggest culprits that cause the timing belt to break, the balance shaft belt. A broken balance shaft belt has no where to go and typically they get lodged into the timing belt or a roller and within secs your timing belt will shread into pieces, causing severe damage.
The original BS belts were 15mm wide and then later upgraded to 18mm (iirc). There was a reason for this. The BS belt stretches and is the weakest link in my opinion, not the timing belt. I have seen this a few times on the 16 valve engines. The balance shaft belt taking the timing belt out.
The original BS belts were 15mm wide and then later upgraded to 18mm (iirc). There was a reason for this. The BS belt stretches and is the weakest link in my opinion, not the timing belt. I have seen this a few times on the 16 valve engines. The balance shaft belt taking the timing belt out.