Fan Belt tension???
#1
Registered User
Thread Starter
Fan Belt tension???
Guys i just replaced my alternator and put the V-belt back on then tightened down the strap that holds the fan unit on. The Fan belt seems pretty tight. Which has me a little worried. I put the pullies back on exactly as they came off with the spacers in the correct places. Will the belt stretch out a little how do i know if its too tight or too loose??
Thanks
JERRY
Thanks
JERRY
#2
Jerry
Kinda difficult to describe how tight a belt should be, but if you grab it with your fingers and move it back and forth you should be able to move it about a 1/2" either side of where it sits naturally. Better to be a little loose and not put too much stress on the bearings than too tight. If you hear it slipping tighten it up a shim at a time.
Hope this helps
Bill
90C2
Kinda difficult to describe how tight a belt should be, but if you grab it with your fingers and move it back and forth you should be able to move it about a 1/2" either side of where it sits naturally. Better to be a little loose and not put too much stress on the bearings than too tight. If you hear it slipping tighten it up a shim at a time.
Hope this helps
Bill
90C2
#3
There's a belt tensioning tool called a Krikit that you can get at AutoZone. See this thread:
https://rennlist.com/forums/showthre...highlight=belt
https://rennlist.com/forums/showthre...highlight=belt
#4
#5
Nordschleife Master
You can't use the old set up for a new set up .
You have got to move the shims around to set up the tension .
"Will the belt stretch out a little"
If its a brand new belt , yes .
If not then no .
" how do i know if its too tight or too loose??"
Set it up to loose and it will squeal .
If it squeals , tighten it up till it no longer squeals .
You have got to move the shims around to set up the tension .
"Will the belt stretch out a little"
If its a brand new belt , yes .
If not then no .
" how do i know if its too tight or too loose??"
Set it up to loose and it will squeal .
If it squeals , tighten it up till it no longer squeals .
Last edited by Indycam; 04-05-2008 at 08:00 PM.
#6
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I used the tension tool but ultimately I came back to what Indy says above. If you think it might be too tight, take it apart and move a shim into the middle of the pulley. If that position causes squealing or obvious slippage then move the shim back. If not, you are ok.
#7
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The factory manual says to use the Porsche tool to measure tension. However, the shim adjustments are pretty coarse. Here is a non-tool method that has worked on my 964 and every previous 911. This will get you to the correct number of shims:
Try turning the crank using a wrench on the alternater pulley nut. If the belt slips easily, it is too loose. If it won't slip, that could be too tight. If you change one shim after finding it too loose, and then it turns the crank, you are dead-on. The belt will settle in, and you know you are not tight enough to damage the alternator. If you can turn the crank with just a little thumb pressure on the slack side of the belt, that is still OK.
Any hint of belt squeal when the engine is running means you are too loose and could damage the belt. Check again after a few drives. I have never needed to make a 2 nd adjustment. Belts have a steel backbone and don't stretch much. The rubber faces can wear and let the belt ride lower in the pulleys.
Try turning the crank using a wrench on the alternater pulley nut. If the belt slips easily, it is too loose. If it won't slip, that could be too tight. If you change one shim after finding it too loose, and then it turns the crank, you are dead-on. The belt will settle in, and you know you are not tight enough to damage the alternator. If you can turn the crank with just a little thumb pressure on the slack side of the belt, that is still OK.
Any hint of belt squeal when the engine is running means you are too loose and could damage the belt. Check again after a few drives. I have never needed to make a 2 nd adjustment. Belts have a steel backbone and don't stretch much. The rubber faces can wear and let the belt ride lower in the pulleys.
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#9
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The factory manual says to use the Porsche tool to measure tension. However, the shim adjustments are pretty coarse. Here is a non-tool method that has worked on my 964 and every previous 911. This will get you to the correct number of shims:
Try turning the crank using a wrench on the alternater pulley nut. If the belt slips easily, it is too loose. If it won't slip, that could be too tight. If you change one shim after finding it too loose, and then it turns the crank, you are dead-on. The belt will settle in, and you know you are not tight enough to damage the alternator. If you can turn the crank with just a little thumb pressure on the slack side of the belt, that is still OK.
Any hint of belt squeal when the engine is running means you are too loose and could damage the belt. Check again after a few drives. I have never needed to make a 2 nd adjustment. Belts have a steel backbone and don't stretch much. The rubber faces can wear and let the belt ride lower in the pulleys.
Try turning the crank using a wrench on the alternater pulley nut. If the belt slips easily, it is too loose. If it won't slip, that could be too tight. If you change one shim after finding it too loose, and then it turns the crank, you are dead-on. The belt will settle in, and you know you are not tight enough to damage the alternator. If you can turn the crank with just a little thumb pressure on the slack side of the belt, that is still OK.
Any hint of belt squeal when the engine is running means you are too loose and could damage the belt. Check again after a few drives. I have never needed to make a 2 nd adjustment. Belts have a steel backbone and don't stretch much. The rubber faces can wear and let the belt ride lower in the pulleys.
#10
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Thanks guys for your help
JERRY
#11
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By the way, NAPA no longer carries Gates products. Gates makes their belts, but the tool is no longer available from them. CarQuest sells Gates, they had the Gates Krikit #91107 tension tool in stock. $12.
#12
Rennlist Member
belt tension
was up!!!!!!!!!!!!!!!!!!!!!!
those that recommended the Krikit tool are right on. it cost 10 dallars or so and works like a charm. no trees needed
those that recommended the Krikit tool are right on. it cost 10 dallars or so and works like a charm. no trees needed
#13
Burning Brakes
I give up - What are the belt tensions supposed to be?
OK after hours of research on belts, updated pulleys, RS single pulley systems, Clewette serpentine system and actual $15 belt tension gauge the ONLY question that I can not find an answer to on this site is.....
What are the factory recommended tension numbers for all three belts?
I know which tension gauge to get and I know how to use it after watching a video but dang it, no one actually lists the numbers that each belt is supposed to be tightened to.
TIA
What are the factory recommended tension numbers for all three belts?
I know which tension gauge to get and I know how to use it after watching a video but dang it, no one actually lists the numbers that each belt is supposed to be tightened to.
TIA