Timing belt tensioners

bill ward · 05-07-2010, 02:40 PM

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

cgt · 05-08-2010, 03:18 AM

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.

bill ward · 05-08-2010, 11:53 AM

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

Gcalo · 05-08-2010, 02:43 PM

Stay w/OEM but compare them to VW Jetta and Passat.

Very similar items! Almost identical.

How interesting!!!

bill ward · 05-09-2010, 08:12 AM

Sir-
In what ways are they similar/different?

Gcalo · 05-09-2010, 08:30 AM

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.

bill ward · 05-09-2010, 09:35 AM

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

bill ward · 05-14-2010, 02:28 PM

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

Gcalo · 05-14-2010, 02:53 PM

Heat as well as tension affects spring life.

I think you solved the problem.

bill ward · 09-11-2010, 04:42 PM

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.

Gcalo · 09-11-2010, 09:12 PM

Go through it bit by bit but do use new belts.

This is a strange one.

bill ward · 09-12-2010, 11:38 AM

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.

Gcalo · 09-12-2010, 11:40 AM

Stone guard could not hurt.

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

05-07-2010, 02:40 PM	#1
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	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

09-11-2010, 04:42 PM	#10
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	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 04:49 PM.

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05-08-2010, 03:18 AM	#2
cgt Owner Elite Member Join Date: Sep 2008 Location: London, UK Ferrari Life Posts: 104	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.

05-08-2010, 11:53 AM	#3
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	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

05-08-2010, 02:43 PM	#4
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	Stay w/OEM but compare them to VW Jetta and Passat. Very similar items! Almost identical. How interesting!!!

05-09-2010, 08:12 AM	#5
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	Sir- In what ways are they similar/different?

05-09-2010, 08:30 AM	#6
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	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.

05-09-2010, 09:35 AM	#7
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	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

05-14-2010, 02:28 PM	#8
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	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

05-14-2010, 02:53 PM	#9
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	Heat as well as tension affects spring life. I think you solved the problem.

09-11-2010, 09:12 PM	#11
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	Go through it bit by bit but do use new belts. This is a strange one.

09-12-2010, 11:38 AM	#12
bill ward Owner Elite Member Join Date: Jun 2008 Location: Three forks, MT,USA Ferrari Life Posts: 90	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.

09-12-2010, 11:40 AM	#13
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	Stone guard could not hurt. I once saw photo of a timing belt w/impression of a nickel in it!