Winter Ferrari Drive

Well, I would not drive in the snow or rain but it is technically winter. I do like to drive the car every weekend after work. This is my 'belt test.' Looks like they did not pop today so, another happy ride. I don't like to go more than one or two weekends without a belt test. Once it starts to snow I have to compromise a little.

These timing belt thread probably now all belong in "Politics and Religion."

One thing I know does not exist is an assesment of "risks" of the belt change procedure. What is the incidence of: faulty new belt, un-tensioned new belt, mis-placed new belt, dings and dents on the body, damage from storage while waiting for whatever, damage to delicate interior components, missing toolkits, missing manuals and missing jacks, water leaks, oil leaks, new noises, new vibrations, missing fasteners etc.

I have seen many posts that start out "My Ferrari is messed up..." only to find on a later post that "...it was recently serviced by xxxx...."

Lets do some math, 1986-2007 = 21yrs; 21yrs/3yrs = 7; 7 x $5000 = $35,000. The monetary incentive here would be to NOT replace the belts until they break or the engine needs to come out for some other reason.
Image Unavailable, Please Login

 

True, no logic really; when and how often to change belts is based more on a belief system (like a religion) than on factual data (as I had previously posted, no way to make a risk/benefit model for frequency of change as there is no risk data for the procedure).

Like if you have a 4.5 cm aneurysm, I know it will grow with time and eventually rupture, but the risk of rupture is so small at 4.5 cm that the risk of surgical correction outweighs the risk of rupture so: no operation. If I could do the operation with zero risk then I would do all the 4.5 cm aneurysms out there.

Trying to find factual data to support ANY belt-change algorthm in f-chat threads is like trying to find the meaning of God in the "politics and religion section."

But, how do I feel about it? I think a recommendation for a 3 year belt change interval is as crazy as if the American College of Cardiology came out with recommendations for stenting 4 cm aneurysms when there is no long term data for aortic stents and the risks are not fully elucidated and the long term benefit is not clear. Especially in the light of the extensive long term risk and benefit data on surgical repair of aneurysms (which does not support surgical repair at 4 cm).

 

I guess you guys have never read the "Ferrariham Study!"


THE FERRARIHAM STUDY

by I. B. Fast, B. R. Akem, W. E. Testum

Research Sponsored by ferrarichat.com

INTRODUCTION:

Debate over the optimum interval for prophylactic timing belt replacement in Ferrari automobiles with interference-type design has been fueled by misunderstanding, folklore, urban legends and greedy service establishments. FNA has been little help in making order of the chaos.

In this pivotal study of Ferrari life history, we hope to understand timing belt failure statistics such that meaningful recommendations can be given to owners and service establishments.

MATERIALS AND METHODS:

10,332 interference engine Ferrari automobiles were enrolled in the study and followed for 20 years from 1985 to 2005. Models included were 308 quatrovalvole, testarossa, 512TR, 328, 365 Boxer and 512 Boxer. Data was recorded by independent observers based on initial reports from service technicians and owners.

End points were timing belt failure and automobile insurance ‘write off’ from all causes.

RESULTS:

Overall automobile survival (freedom from being ‘written off’) during the study was excellent, at 98%

11 timing belts failed during the study period. Of these failures 9 lead to interference-related internal engine damage. 2 belts were removed and replaced without internal engine damage.

One belt failed at 5 days following replacement and an original belt failed at 28.6 years.
The median time interval for timing belt failure was 12 years +/- 7 years.

Average mileage on a timing belt at the time of failure was 18,000 miles +/- 20,000 miles (incredible variance)

Subset analysis of failure comparing failure between automobile models did not show a significant difference between the 8 cylinder and 12 cylinder models. (p = 2.03)

The risk of timing belt failure increased with increasing belt age and with increasing mileage. Though numbers were low, there was a slight trend toward a non-linear increase in failure with belt age over 10 years.

Complications from timing belt replacement included catastrophic belt failure (secondary to improper installation), return to service center in 30 days or less, oil leak, non-function of ancillary equipment, cosmetic defects requiring repair. Overall complication rate was 23%.

A linearized Cox hazard proportional analysis of timing belt failure data demonstrated a 0.06 risk per year of timing belt failure.

Timing belts that were removed during prophylactic replacement and belts that failed in service were analyzed.

With respect to belts removed prophylactically, 88 % of belts were classified as normal upon removal. 18% of belts demonstrated some degree of cracking. 2% of belts demonstrated one or more ‘broken’ rubber teeth.

Belts analyzed from engines diagnosed with ‘Broken timing belt’ demonstrated sheared off teeth in 95%, unusual wear marks (jumped belts?) in 4% and belt fracture or tear in 1% (foreign body)

Cost benefit analysis was based on cost of timing belt change and associated required services and was estimated to be $5000. Automobiles were considered to have ‘frozen’ value throughout the time of the study (neither appreciating nor depreciating). Repair costs for engine repair following belt failure was estimated to be $23,000.

Different timing belt change intervals were fed into the ‘failure’ model and multiple thee-way hazard function plots were obtained for 3, 5, 8, 10 and 15 years replacement intervals. For belt replacement intervals of 3 years, the cost benefit function was high early on, lowest at 8.5 years and increased again to 12 years where again after 13 years it tapered off, as an indication that the cumulative cost of the prophylactic belt replacement was nearing the value of the automobile. This 3 year strategy incurred the greatest cost.

The optimum cost-benefit strategy was observed when an 8 year replacement interval was fed into the model (p = .038).

In addition, a bivariate analysis of risk and benefit from timing belt failure (to take into account service ‘mistakes’) indicated an ideal replacement interval of 10 years (based on an instantaneous risk of 0.06 per year and a risk of immediate failure following prophylactic replacement of 0.01%)

Conclusions:

Prophylactic replacement of timing belts in interference-type Ferrari engines has been the topic of many discussions, but as of yet, no study had been undertaken to determine the actual risks, and costs involved. This is the first study of its kind and the authors would like to think that the controversy over when to change timing belts would finally be resolved. Of course, ownership of an automobile does provide supreme authority to the owner to ‘do as he pleases’ and our recommendations ignore the ‘emotional value’ of these automobiles. Although the risk of belt failure is rare even at 6 to 8 years in our study, a ‘valued possession’ may be best served with a more frequent belt service interval, assuming a competent shop is available.


(I did not mean to start another thread on belt failure, just some entertainment for the holidays; HAPPY HOLIDAYS and a wish of many miles of Ferrari driving for the new year)