Timing belt tensioners - Ferrari Life
 
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post #1 of 13 Old 05-07-2010, 03:40 PM Thread Starter
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Timing belt tensioners

Alright Guys-
308 did jump time- approx. one tooth of belt. took all apart cleaned, reset and re-tensioned belt. Still at a loss why it jumped time. Bearing, tensioners,cam bearings, belt- everything looks perfect. What am I missing? Does anyone know a measurable belt preload besides the turn engine over to set preload then lock down? Is there an aftermarket tensioner that would act dynamically per newer cars? I don't want to finish job w/o answer as to why or next time maybe fatal.
Any ideas will be tested. Thanks, Bill
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post #2 of 13 Old 05-08-2010, 04:18 AM
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Cant answer in detail Bill but I always insist on Hill Engineering tensioners and bearings in any Ferrari. They are far superior to the factory items.
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post #3 of 13 Old 05-08-2010, 12:53 PM Thread Starter
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I'm not adverse to replacing bearing with Hill's, but I think my problem lies in tensioners themselves. Do you know of anything better than 30 year old ones? Bill
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post #4 of 13 Old 05-08-2010, 03:43 PM
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Stay w/OEM but compare them to VW Jetta and Passat.

Very similar items! Almost identical.

How interesting!!!
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post #5 of 13 Old 05-09-2010, 09:12 AM Thread Starter
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Sir-
In what ways are they similar/different?
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post #6 of 13 Old 05-09-2010, 09:30 AM
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Ferrari use a great deal of German parts.

On the 360's the tensioners are nearly identical to Jetta/Passat!

So take one out and compare it to some German makes. You might be surprised.

I think your issue is weak springs.
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post #7 of 13 Old 05-09-2010, 10:35 AM Thread Starter
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Thank You-
Weak springs is the direction I've been thinking. Also, I noticed that the ear on tensioners that retains springs appears to have been bent past 90 degree. All pictures I've been able to find show this at apparent 90 degree. Possibly someone bent it to apply more spring tension. I believe that this might cause plunger to catch and not work correctly? In bench testing it doesn't but what about in the real world? I'm gathering that this system works fine 99% of time and doesn't need updating- just newer parts? Thanks again, Bill
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post #8 of 13 Old 05-14-2010, 03:28 PM Thread Starter
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Springs!
I received new springs this afternoon. Measured tensioner extended length @ 2.910" and disassembled. Installed new spring and replaced to car.Before setting tension was @ 2.924" and after setting reads 2.934. Belt feels tighter too. I hope this was the problem but we'll see after driving awhile. Old spring looks shorter too- hard to measure due to compression. I think I'm going to order 2 more springs just to have ready next time. Thanx for all your help. Bill
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post #9 of 13 Old 05-14-2010, 03:53 PM
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Heat as well as tension affects spring life.

I think you solved the problem.
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post #10 of 13 Old 09-11-2010, 05:42 PM Thread Starter
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Guess who jumped time again?
Reckon I should be thankful it's end of season and no engine damage done, but I'm flustered. I plan to redo complete belt change, check all bearings, tensiioners, replace with new hill etc-what am I missing? any input will be applied- I've got all winter and want to be 110% this time. The other funny thing is that this only happens on gravel (yes I know) I live on.Thinking maybe shouldn't have re-used belts.

Last edited by bill ward; 09-11-2010 at 05:49 PM.
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post #11 of 13 Old 09-11-2010, 10:12 PM
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Go through it bit by bit but do use new belts.

This is a strange one.
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post #12 of 13 Old 09-12-2010, 12:38 PM Thread Starter
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Got it apart and found 1/4" tear through belt. I'm betting it's damage from a piece of gravel. My father posed question of weak valve spring and back fire causing cam to jump as it was only one cam (intake) off by one tooth again. Have checked valve springs short of removal of head- going to do a leak down test next week. Still, seems gravel will be an ongoing problem. Has anyone tried "cam Belt stone guards #30813815 from Superformance? Any draw backs? I'm still going to re-do complete belt job and hope this is problem.
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post #13 of 13 Old 09-12-2010, 12:40 PM
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Stone guard could not hurt.

I once saw photo of a timing belt w/impression of a nickel in it!
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