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Old 05-25-2020, 12:00 AM   #1
Nickagriffin
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Default Skipped timing teeth under load

Hey all,

I scoured the forums for an answer to this but couldn't find anything. I was doing a WOT pull today at about 15lbs (13c) and the timing belt skipped a tooth. I've never heard of this happening but I'm assuming the torque made this happen? Is there any way to make sure this won't happen again? I think the stock tensioner was adjusted properly.
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Old 05-25-2020, 12:22 AM   #2
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Quote:
Originally Posted by Nickagriffin View Post
Hey all,

I scoured the forums for an answer to this but couldn't find anything. I was doing a WOT pull today at about 15lbs (13c) and the timing belt skipped a tooth. I've never heard of this happening but I'm assuming the torque made this happen? Is there any way to make sure this won't happen again? I think the stock tensioner was adjusted properly.
Was the belt new? How many miles on the timing gears? I don't think the torque coming out of the back of the motor has much to do with the timing function.
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Old 05-25-2020, 12:24 AM   #3
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I'm not positive but I think I changed it when I rebuilt the engine last year. Probably like 3000 miles since then. The timing gears probably have like 250k on them if I had to guess. I just thought since the torque on the crankshaft was a lot higher it could make it skip bc of the resistance of the cam pulley but if guys are running unmodified high hp builds then my problem is probably something else.
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Old 05-25-2020, 12:29 AM   #4
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Just checked. Definitely replaced it but I used a cheap IPD one
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Old 05-25-2020, 01:02 AM   #5
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It’s happened to me when using a square tooth belt. I just give them a smidge of extra tension when installing them now.
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Old 05-25-2020, 01:08 AM   #6
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It’s happened to me when using a square tooth belt. I just give them a smidge of extra tension when installing them now.
Makes sense. Do you know if the round belts and pulleys are any more secure?

Thanks
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Old 05-25-2020, 04:47 AM   #7
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Makes sense. Do you know if the round belts and pulleys are any more secure?

Thanks
Yes.
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Old 05-25-2020, 11:34 AM   #8
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Makes sense. Do you know if the round belts and pulleys are any more secure?

Thanks
As diabetuuuuus above mentioned, the round tooth profile is better.
That being said, just a slight preload on the square tooth, or adjusting after a few hundred miles and then every oil change seems to keep them in check as well.
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Old 05-25-2020, 02:36 PM   #9
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Don't rely on the spring tension. I smack mine tight with a flathead screwdriver and a hammer and recheck the tension.
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Old 05-25-2020, 02:40 PM   #10
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you are supposed to reset the tension after running in
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Old 05-25-2020, 03:21 PM   #11
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^^ Yes. That is what the rubber plug in the timing cover is for. It takes about 1,000 miles for the belt to seat in and stretch the small amount it does initially.
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Old 05-25-2020, 05:24 PM   #12
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I believe it's supposed to be rechecked for tension every so often as well. Every oil change seems like a safe number.
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Old 05-25-2020, 06:39 PM   #13
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I retensioned it relatively recently, definitely a while after I replaced it. Anyways, I put it back on with a little more tension and it seems to be holding better now.
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Old 05-26-2020, 01:58 AM   #14
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What'd you do to re-tension the belt?

Make it tight, but not "play the harp" tight.
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Old 05-26-2020, 12:53 PM   #15
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Used a breaker bar to push against the backside, but only a little. Can still turn it about 75 degrees with my hand instead of the normal 90 degrees.
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Old 05-26-2020, 02:39 PM   #16
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Quote:
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Used a breaker bar to push against the backside, but only a little. Can still turn it about 75 degrees with my hand instead of the normal 90 degrees.
Turn what 75 degrees?
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Old 05-26-2020, 03:44 PM   #17
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I think he is twisting the longest part of the belt.
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Old 05-26-2020, 05:13 PM   #18
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Quote:
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I think he is twisting the longest part of the belt.

^^ This. Sorry shouldve specified
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Old 05-27-2020, 06:39 AM   #19
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Next time you have her apart, convert to round tooth..... and of course check the belt tension as the OE specified. Amazing how well these engines will run when you follow directions......
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