Do I have timing belt whine?
12-12-2018, 05:19 PM
#16
Intermediate
As promised I post my updates. Hope I'm not boring anyone.
2nd attempt. Slightly less tension. Idler positioned with 0.5mm lower gap (credit card setup) and about 0.1mm upper gap.
3rd round. Even less tension. 180 degree twist could be done when idler is not installed. 0.5mm lower gap, and abou 0.1mm upper lift (when a tip is at the idler, when there is a walley there is a small gap)
Honestly I do not hear much difference in the 3 setup. I'm thinking about removing the balance belt just to double check if it is really the cause. I do not feel safe to lower the tension any more.
Indeed Porsche only suggested just a bit lower tension for the 18mm balance belt than the new T belt according to Clark's. ( New belt - 4.0 ą0.3 , New style belt (18 mm wide) - 3.5 ą 0.5 whatever those numbers are...)
2nd attempt. Slightly less tension. Idler positioned with 0.5mm lower gap (credit card setup) and about 0.1mm upper gap.
Honestly I do not hear much difference in the 3 setup. I'm thinking about removing the balance belt just to double check if it is really the cause. I do not feel safe to lower the tension any more.
Indeed Porsche only suggested just a bit lower tension for the 18mm balance belt than the new T belt according to Clark's. ( New belt - 4.0 ą0.3 , New style belt (18 mm wide) - 3.5 ą 0.5 whatever those numbers are...)
12-12-2018, 09:28 PM
#17
Drifting
I'd say the second one above is a bit like mine after the engine has been sitting for a while, like a couple of weeks or more. The last time it sat so long, I was doing big repairs. After starting, it whined like that until I drove a bit, then gone.
Leave it as is and drive around for a few days. It just might settle down
Leave it as is and drive around for a few days. It just might settle down
12-13-2018, 12:11 AM
#18
As promised I post my updates. Hope I'm not boring anyone.
2nd attempt. Slightly less tension. Idler positioned with 0.5mm lower gap (credit card setup) and about 0.1mm upper gap.
https://youtu.be/WaRoEddgk3o
3rd round. Even less tension. 180 degree twist could be done when idler is not installed. 0.5mm lower gap, and abou 0.1mm upper lift (when a tip is at the idler, when there is a walley there is a small gap)
https://youtu.be/7y4XLFSBFHo
Honestly I do not hear much difference in the 3 setup. I'm thinking about removing the balance belt just to double check if it is really the cause. I do not feel safe to lower the tension any more.
Indeed Porsche only suggested just a bit lower tension for the 18mm balance belt than the new T belt according to Clark's. ( New belt - 4.0 ą0.3 , New style belt (18 mm wide) - 3.5 ą 0.5 whatever those numbers are...)
2nd attempt. Slightly less tension. Idler positioned with 0.5mm lower gap (credit card setup) and about 0.1mm upper gap.
https://youtu.be/WaRoEddgk3o
3rd round. Even less tension. 180 degree twist could be done when idler is not installed. 0.5mm lower gap, and abou 0.1mm upper lift (when a tip is at the idler, when there is a walley there is a small gap)
https://youtu.be/7y4XLFSBFHo
Honestly I do not hear much difference in the 3 setup. I'm thinking about removing the balance belt just to double check if it is really the cause. I do not feel safe to lower the tension any more.
Indeed Porsche only suggested just a bit lower tension for the 18mm balance belt than the new T belt according to Clark's. ( New belt - 4.0 ą0.3 , New style belt (18 mm wide) - 3.5 ą 0.5 whatever those numbers are...)
If satisfied with the credit card method on Svens video then Adjust the idler pulley on balancing belt a bit more depending on the twist and go for another drive. Then when you get home twist the belt again by hand and you will notice the difference. Like it will go about 100 degree twist is all. Make sire car is OFF while twisting belts.
Next day do this again and listen to whine. I kept doing this til whine was ever so slight. Also whine is worse sometimes with AC on so leave that off. Note: put on some of those rubber gloves first cuz it always leaves black on your fingers.
You should not hear the whine from inside car while driving or something is off.
If you notice any belt shavings around then it may be that rail or some other thing is rubbing. At least with the cover off you can check it here and there and adjust quickly til it sounds right
To me even that second video #3 above sounds like too much whine but better.
FWIW I have never had a need for belt tensioning tools. I just hear or feel its off and this one sounds a bit off still but getting very close. First video #2 has something way way too tight or rubbing somewhere.
Keep an eye on it for a week or so and make some more very slight adjustments and see what it does. Dont rev the car too high like under 3k rpm til you get it squared away
Patience is key. Check it. Drive it. Adjust it. Repeat a few times and you will be good.
Also after whine goes away in 6 months check it. Drive it. Tighten it a bit for a few days and you are set for another 40K. Remember to put top cover back on.
12-13-2018, 01:42 AM
#19
Intermediate
I'd say the second one above is a bit like mine after the engine has been sitting for a while, like a couple of weeks or more. The last time it sat so long, I was doing big repairs. After starting, it whined like that until I drove a bit, then gone.
Leave it as is and drive around for a few days. It just might settle down
Leave it as is and drive around for a few days. It just might settle down
I've read somewhere that some whine is ok still the engine warms up.
Shall I run a quick test with balance belt off just to get sure about the root cause?
12-13-2018, 09:04 AM
#20
Drifting
You'll be fine
12-13-2018, 01:43 PM
#22
Intermediate
I went for a final round. And yes. For me it will remain as this:
I've tightend just a little bit. It is about 135-150degree right now. Still the belt is very loose.
And I've set up the idler that there is the banc card gap at the bottom, and 0,5mm gap at the top.
Now the idler barely turns. I'm vey happy with that.
And I've set up the idler that there is the banc card gap at the bottom, and 0,5mm gap at the top.
Now the idler barely turns. I'm vey happy with that.
12-15-2018, 05:29 AM
#25
Rennlist Member
OK guys - I need your help. I just got done with my timing / balance belt and water pump change. Got the car started and I was so proud that the engine was idling relatively smooth. I come inside and my wife says, "what is that whine?".
I swear I didnt hear it, but after my wifes comment I think I have the dreaded whine. I took a short video. Can you guys watch it and give me some ideas to proceed? I think the whine is accentuated on the video and it doesnt sound that bad IMO.
944 porsche timing belt change - YouTube
I read that whine is due to incorrect belt tension. I adjusted the timing belt to 90 degree bend and balance belt to 180 degree bend. Everything is brand new and the car is on the jack stands.
I was thinking that I should drive it for 20-30 miles just to let the belt "seat" and clean off any assembly oils etc. I used a stethoscope and noise seems very loud around the cam. I checked the CAM toward the back of the engine and it was loud back there too...
I also noticed that the V-belt pulley at the crank was tight but wobbly as it rotated. I guess that wasnt put on properly. Is that keyed? I dont remember a stud or keyway.
I swear I didnt hear it, but after my wifes comment I think I have the dreaded whine. I took a short video. Can you guys watch it and give me some ideas to proceed? I think the whine is accentuated on the video and it doesnt sound that bad IMO.
944 porsche timing belt change - YouTube
I read that whine is due to incorrect belt tension. I adjusted the timing belt to 90 degree bend and balance belt to 180 degree bend. Everything is brand new and the car is on the jack stands.
I was thinking that I should drive it for 20-30 miles just to let the belt "seat" and clean off any assembly oils etc. I used a stethoscope and noise seems very loud around the cam. I checked the CAM toward the back of the engine and it was loud back there too...
I also noticed that the V-belt pulley at the crank was tight but wobbly as it rotated. I guess that wasnt put on properly. Is that keyed? I dont remember a stud or keyway.
Have you heard of a Kricket belt tension tool? I use them on all the belts, 944 and 928. I do have a more expensive Kempf tool for the 928 but I'm not certain it does a better job than the Kricket.
I've never had problems with the Kricket on the 944, it seems to work well with all the belts, including the timing and balance shaft. I think I can recommend it. A set of two (big and little) shouldn't cost much more than $20. You can find them on Amazon.
Regards,
12-15-2018, 08:15 PM
#26
I went for a final round. And yes. For me it will remain as this:
https://youtu.be/FsARlhYW6wY
I've tightend just a little bit. It is about 135-150degree right now. Still the belt is very loose.
And I've set up the idler that there is the banc card gap at the bottom, and 0,5mm gap at the top.
Now the idler barely turns. I'm vey happy with that.
https://youtu.be/FsARlhYW6wY
I've tightend just a little bit. It is about 135-150degree right now. Still the belt is very loose.
And I've set up the idler that there is the banc card gap at the bottom, and 0,5mm gap at the top.
Now the idler barely turns. I'm vey happy with that.
if you like the louder whine now you can move the idler more into the belt and get a nice sound out of it on purpose just to make it sound like its supercharged. Haha. It does tend to wear your idler prematurely however so keep an extra one on hand if you do and want to play with it.
I would drive It like this for a month or so with top cover off and just check tension maybe once a week by twisting it. No more adjusting it but just check it to see how it behaves before and after a drive. You will be amazed as Dan mentioned how floppy it gets over time.
nice job and enjoy!