Early vs Late Belt Tensioner?
#1
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Am about to begin my first DIY cam belt replacement. Been doing lots of reading and watching trying to learn more. All online tutorials I have seen are for the earlier tensioning system. I have an '87 924S with the spring tensioner. Are there significant differences? Can anyone link me to info on the spring tensioner type?
#2
Rainman
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it takes another step or two to put the new belt on, but the tensioner usually sets itself to the right amount.
let the tensioner go to full tension position and check the tension of the belt on the straight span from cam gear to crank gear, without the idler installed. you should be able to twist the belt no more than 90 degrees between thumb and index finger without too much effort. if you cant twist 90 degrees, use the balance shaft spanner wrench (or a 3/8 breaker bar fits into a slot in the tensioner arm) to back some tension off until you can. then lock the bolt/nut down, and check the tension again, and move on.
let the tensioner go to full tension position and check the tension of the belt on the straight span from cam gear to crank gear, without the idler installed. you should be able to twist the belt no more than 90 degrees between thumb and index finger without too much effort. if you cant twist 90 degrees, use the balance shaft spanner wrench (or a 3/8 breaker bar fits into a slot in the tensioner arm) to back some tension off until you can. then lock the bolt/nut down, and check the tension again, and move on.
#3
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Thank you Spencer. Do I understand that I don't need the expensive tensioner gauge to do the job?
That's what I would call technological progress!
That's what I would call technological progress!
#4
Three Wheelin'
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Jim, there's a big difference in how you set the motor up before you release the tensioner. You DON'T wind the motor back 10 degrees from TDC.
Wind the motor in the direction of rotation to TDC and stop there!
Since the spring tensioner works in different fashion to the earlier setup, you're taking up the slack on a different part of the belt. This is why the different approach.
The factory workshop manual is a little cryptic, but the info is there: https://rennlist.com/forums/924-931-...l#post10804511
Cheers,
Mike
Wind the motor in the direction of rotation to TDC and stop there!
Since the spring tensioner works in different fashion to the earlier setup, you're taking up the slack on a different part of the belt. This is why the different approach.
The factory workshop manual is a little cryptic, but the info is there: https://rennlist.com/forums/924-931-...l#post10804511
Cheers,
Mike
#5
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Thank you Mike. The link leads to a very helpful thread and video I had not seen. I'm sure I will have more questions when I get into the project in a couple of weeks. Appears I don't absolutely need a gauge which is good news.
#6
Three Wheelin'
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Hi Jim, yep it's one of those "easy once you know how" jobs.
I've always had good results checking the spring tensioner against the Arnworkx tool, enough to rely on the spring tensioner.
Of course you still need some way of setting the tension on the balance belt!
Cheers,
Mike
I've always had good results checking the spring tensioner against the Arnworkx tool, enough to rely on the spring tensioner.
Of course you still need some way of setting the tension on the balance belt!
Cheers,
Mike
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#8
Proprietoristicly Refined
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Nah, I use the Krikit. Actually now I use nothing but the touch method for the balance belt.
I do back up the crank 5 to 7 degrees to set the cam belt using the 924S mechanical belt tensioner. But the final test is by touch--- cam belt pressure on the water pump pulley. You see, if the cam belt has too much pressure on the WP pulley, it will burn out the WP seal and bearing at some point.
The Arnnworx tool is a bargain for a beginner. $165 well spent. Lets you sleep at night and not wake up in a cold sweat.
J_AZ
I do back up the crank 5 to 7 degrees to set the cam belt using the 924S mechanical belt tensioner. But the final test is by touch--- cam belt pressure on the water pump pulley. You see, if the cam belt has too much pressure on the WP pulley, it will burn out the WP seal and bearing at some point.
The Arnnworx tool is a bargain for a beginner. $165 well spent. Lets you sleep at night and not wake up in a cold sweat.
J_AZ
#9
Three Wheelin'
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Nah, I use the Krikit. Actually now I use nothing but the touch method for the balance belt.
I do back up the crank 5 to 7 degrees to set the cam belt using the 924S mechanical belt tensioner. But the final test is by touch--- cam belt pressure on the water pump pulley. You see, if the cam belt has too much pressure on the WP pulley, it will burn out the WP seal and bearing at some point.
The Arnnworx tool is a bargain for a beginner. $165 well spent. Lets you sleep at night and not wake up in a cold sweat.
J_AZ
I do back up the crank 5 to 7 degrees to set the cam belt using the 924S mechanical belt tensioner. But the final test is by touch--- cam belt pressure on the water pump pulley. You see, if the cam belt has too much pressure on the WP pulley, it will burn out the WP seal and bearing at some point.
The Arnnworx tool is a bargain for a beginner. $165 well spent. Lets you sleep at night and not wake up in a cold sweat.
J_AZ
And +1 for the "can I sleep at night?" test!
#13
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Little bit of OT: which belt rollers are different between 8v and 16v engines?
#14
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