Oh no, did my car die today? No compression and no start.
11-03-2010, 05:05 AM
#16
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1980 Euro s 4.7, single dist driven off the 5/8 cam, cis injection.
Pull off an intake tube and watch the cam gear and belt while cranking to see if it is tracking and moving as expected.
Put a timing light on #1 plug wire and check the timing. If it is OK, the 5/9 cam is likely still in correct timing, if not the timing is off on both cam and distributor (slipped timing belt, stripped teeth, etc).
Pull the covers and inspect the belt, and check timing on both cams.
No compression, my wild guess is that cam timing is off due some failure in the system, belt, tensioner, pulleys, or water pump. Everything needs to be checked when replacing a belt.
Pull off an intake tube and watch the cam gear and belt while cranking to see if it is tracking and moving as expected.
Put a timing light on #1 plug wire and check the timing. If it is OK, the 5/9 cam is likely still in correct timing, if not the timing is off on both cam and distributor (slipped timing belt, stripped teeth, etc).
Pull the covers and inspect the belt, and check timing on both cams.
No compression, my wild guess is that cam timing is off due some failure in the system, belt, tensioner, pulleys, or water pump. Everything needs to be checked when replacing a belt.
11-03-2010, 05:18 AM
#17
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Simon,
I have experienced something very similar. When I bought my 928 it had a new timing belt, and I was never told it needed retightening. One day when I started the engine it stuttered and stopped. What had happened is that the TB jumped enough teeth to loose compression. No valves were hit, thankfully.
I changed it myself, it takes some time but it is doable on the street (although I would prefer a garage!). Regarding tightening the belt, I talked to one of the biggest Porsche specialists in Norway (Autotuning) about hiring their tensioner tool, and they did not have one, they just used the old method of twisting the belt 90° (even on the later 32V cars!) so I did the same.
If you need any help, get in touch. I have a couple of 1980 S engines in parts also in case you need something.
I have experienced something very similar. When I bought my 928 it had a new timing belt, and I was never told it needed retightening. One day when I started the engine it stuttered and stopped. What had happened is that the TB jumped enough teeth to loose compression. No valves were hit, thankfully.
I changed it myself, it takes some time but it is doable on the street (although I would prefer a garage!). Regarding tightening the belt, I talked to one of the biggest Porsche specialists in Norway (Autotuning) about hiring their tensioner tool, and they did not have one, they just used the old method of twisting the belt 90° (even on the later 32V cars!) so I did the same.
If you need any help, get in touch. I have a couple of 1980 S engines in parts also in case you need something.
11-03-2010, 05:51 AM
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Simon,
I have experienced something very similar. When I bought my 928 it had a new timing belt, and I was never told it needed retightening. One day when I started the engine it stuttered and stopped. What had happened is that the TB jumped enough teeth to loose compression. No valves were hit, thankfully.
I changed it myself, it takes some time but it is doable on the street (although I would prefer a garage!). Regarding tightening the belt, I talked to one of the biggest Porsche specialists in Norway (Autotuning) about hiring their tensioner tool, and they did not have one, they just used the old method of twisting the belt 90° (even on the later 32V cars!) so I did the same.
If you need any help, get in touch. I have a couple of 1980 S engines in parts also in case you need something.
I have experienced something very similar. When I bought my 928 it had a new timing belt, and I was never told it needed retightening. One day when I started the engine it stuttered and stopped. What had happened is that the TB jumped enough teeth to loose compression. No valves were hit, thankfully.
I changed it myself, it takes some time but it is doable on the street (although I would prefer a garage!). Regarding tightening the belt, I talked to one of the biggest Porsche specialists in Norway (Autotuning) about hiring their tensioner tool, and they did not have one, they just used the old method of twisting the belt 90° (even on the later 32V cars!) so I did the same.
If you need any help, get in touch. I have a couple of 1980 S engines in parts also in case you need something.
especialy when turning off the engine the cams can jump the opposite direction when the belt is loose because of the valve springs are pushing the cam to 45° and the crack stays at the point wher the engine was stopped.
first thing to do =check tb tension .dont turn the engine anymore, check tension, and set the timing marks at zero.
i have changed my tb and waterpump on my driveway,,you will get it warm if you are working so dont worry about 0°temp outside . on the older type its an easy job, i did it in one day.
never did a tb before, i had the porsche a few weeks, so the car was new to me.
i just jacked up the front end, and secure the rear wheels with wooden blocks.
u only need the lock tool and tension tool.
i have a 84 us and non interfearing
Last edited by riviera455; 11-03-2010 at 06:25 AM.
11-03-2010, 06:11 AM
#19
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That sounds scary... Do a search here for the "Kempf Tool" - an inexpensive substitute for the original tensioning tool. It might be a good idea for you to invest in one.
11-03-2010, 06:50 AM
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I had my 944 timing belt done once by a "backwoods" type of mechanic who said not to worry, he could set the tension "by feel." It was a good belt for 40,000 miles, until time for replacement. Experience can do a lot for a mechanic.
11-03-2010, 01:41 PM
#22
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Just my opinion, but I suspect a high percentage of timing belt related failures are from improperly set tension, and most of the rest from general botching of the related work, rebuilding tensioner, replacing bolts and bearings.
Takes a rich man to afford a cheap Porsche.
Takes a richer one to afford a cheap mechanic.
Takes a rich man to afford a cheap Porsche.
Takes a richer one to afford a cheap mechanic.
11-03-2010, 01:58 PM
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AH...."I had my 944 timing belt done once by a "backwoods" type of mechanic who said not to worry, he could set the tension "by feel." It was a good belt for 40,000 miles, until time for replacement. Experience can do a lot for a mechanic." The question is when did he feel a properly tensioned belt and HOW did he KNOW it was proper ??? Setting them too tight will cause as many issues as too loose. At best they just GUESS and sometimes even a blind pig finds an acorn. Besides it is not his money at risk....
11-03-2010, 02:16 PM
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Install a Porkensioner and you won't have to re-tension your belt in 1000 miles. Any you can rest assured that temperature won't ever cause excessive tension on the belt that wears out cam gears and bends bolts. Replace your belt with either an OEM Porsche belt, or one of the new extra strength Gates belts. You can do it yourself! Get your car home and pull the belt covers... It will save you big $$$. You might want to invest in a propane or liquid fuel type heater.... (that you will be able to afford with all the $ you save doing it yourself). Good luck! I will pray for no carbon build up! I only run Chevron with Techron in the hopes of keeping carbon build up to a minimum...
11-03-2010, 02:23 PM
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True that. The factory tension tool is all thats really available, and it is the big bucks... Aircraft mechanics are trained to use the 90 degree twist for cogged belts that have a open span of more than 10 inches. (Hughes Aircraft anyway)... When my first 944 had the whole front end done (cam and ballence belts and all rollers hardware etc.) I checked the tension of the belt by "twist" to see how it felt at correct tension. I retensioned myself after 1000 miles, and had no ill effects. Drove that car for 5 more years after that. I wouldn't do that with a 928 as the Kempf tool is so cheap, or the Porkensioner is an even more elegant solution. 
11-03-2010, 09:38 PM
#27
My 1980S might have died in an expensive way. I had just dropped my son off at the hospital and it wouldn't start afterwards. Turns over fine but not a sign of anything at all. A quick check at the roadside showed there is fuel and there is a strong spark.
After having it towed to the local Porsche garage, they called today and said that there was no compression. But, from what they could see, they thought that the timing belt looked intact (without taking the covers off).
I'm preparing myself for the worst - an expensive repair - at an expensive garage but just want to make sure that they don't jump in and do something really expensive and unnecessary. They want to change the timing belt as part of their fault-finding, but I want to get a second opinion from you guys if there is an alternative?
So, in order of expense - what can the problem be? Can there be no compression and an intact timing belt - my logic says no - but maybe I am wrong.
If the belt has snapped, can I have bent some valves, or is the 80 model a non interference engine?
Should the water pump be changed at the same time? It seems like most do the water pump while they are at it, just want to check.
I have just spent all Summer getting the car back on the road, after a 4 year storage, and was planning to change the belt next summer. Guess I should have done it earlier.
Can anybody shine some light at the end of the tunnel?
After having it towed to the local Porsche garage, they called today and said that there was no compression. But, from what they could see, they thought that the timing belt looked intact (without taking the covers off).
I'm preparing myself for the worst - an expensive repair - at an expensive garage but just want to make sure that they don't jump in and do something really expensive and unnecessary. They want to change the timing belt as part of their fault-finding, but I want to get a second opinion from you guys if there is an alternative?
So, in order of expense - what can the problem be? Can there be no compression and an intact timing belt - my logic says no - but maybe I am wrong.
If the belt has snapped, can I have bent some valves, or is the 80 model a non interference engine?
Should the water pump be changed at the same time? It seems like most do the water pump while they are at it, just want to check.
I have just spent all Summer getting the car back on the road, after a 4 year storage, and was planning to change the belt next summer. Guess I should have done it earlier.
Can anybody shine some light at the end of the tunnel?
Timing belts do slip without breaking, and some 80 cars have an extra idler bearing and some do not. Mine slipped, and now I have the bearing and a new belt. Or at least the new owner does.
11-04-2010, 12:36 AM
#28
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Well, when mine gave out on I95 coming out of Richmond VA, the car acted just like it ran out of gas. It would then sound like it wanted to start. I even jumpered the fuel pump relay to try to get home. I couldn't tell untill I pulled all the TB covers, there was a mess of black rubber shreds at the bottom. Turns out that the wrong sholder bolt was put back into one of the rollers. New belt and bolt and it was good as new. Don't forget to retension in 1k miles...
Good luck,
Good luck,
11-04-2010, 01:10 AM
#29
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When the old very brown 1980 USA 4,5 jumped timing as I came in off the track at Willow springs after 15 minutes of driving as fast as humanly possible it just sputtered once at idle then when cranking it was faster than normal.......I knew the belt had lost timing so I had it towed to 928 International put on a belt and it was good to go !
11-05-2010, 05:18 AM
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Thanks for all of the advice.
I have decided to let the garage do the work for me. Its minus 4C today, and I just dont have the time or motivation to do a street change of the belt. It will cost med $$$, but the only other alternative for me is to store it over winter and do it in the spring.
As Danglerb put it - Takes a rich man to afford a cheap Porsche. I am beginning to understand that (not that I am a rich man, and definately not after a belt change).
I have decided to let the garage do the work for me. Its minus 4C today, and I just dont have the time or motivation to do a street change of the belt. It will cost med $$$, but the only other alternative for me is to store it over winter and do it in the spring.
As Danglerb put it - Takes a rich man to afford a cheap Porsche. I am beginning to understand that (not that I am a rich man, and definately not after a belt change).