360 Timing Belts

ha ha, yes another timing belt thread. Easiest way to research is to throw out a question and wait for the responses.

Technology advances and things get better (usually). Are the current belts being sold for the 360 the same as in 1999, or is the construction different? If different, did the tightening specs change, i.e. freq? I recall that the 550 had a belt upgrade at some point. Did the tightening specs get revised with that belt change? It would seem that a change in construction (e.g. stiffness) would change the frequency response with tension.

 

Seems like a question for Daniel at Ricambi. He is the expert on parts changes and updates.

 

Wouldn’t that kind of change have been accompanied with a TSB?

 

Even if the construction changed I would be shocked if they updated the service manual. Once the car is no longer made the manufacturer (the one setting that spec) stops doing work on and updating things for that car, they have something new to invest time and energy into. IE: they aren't going to re-qualify parts for an old car. The same happens for fluids. If they call for Dexron III they won't EVER go change that even if it is NLA. They just move ahead with the new stuff on newer cars.

 

I did a quick check on Ricambi and google. It would appear the 355 and 360 share the same timing belts. The belt part number (appears) to have always been the same for the 360, but did change once or twice for the 355. So the one used on the 360 was consistently the same? Again, not confirmed, but what I could find in a 5 minute check.

 

I have a source that shows for the 360 belt a part number sequence of 154378, 181610 then 184986.

 

Here is an old thread from 2005, so this belt has been in service for a long time. Also means the tightening spec has been used on this belt for a long time.
https://www.ferrarichat.com/forum/threads/tech-folks-belt-184986.58152/

 

Seems the tech department never got back to him, its only been fifteen years, we might see a response back yet.

 

And a new part number.

Current number 184986 has been around since about 2002 so no changes since then.

 

Kevlar belts were introduced on the 575M early in production in 2002 and that would seem to match up with the dates on the latest 360 belts. 360 part number 184986, 575M part number 187744, so similar time period with the higher production V8 belt coming before the V12 belt. The new V12 belt was to be used on the 456-612 models.

In theory, belt construction will not have a large influence on frequency.

 

Correct. Frequency is a function of length and tension. Think about a guitar with steel strings vs nylon, they still have the same primary frequency.

 

I know people might be tired of hearing about timing belts so I did a search and am posting my latest experience in the latest thread on the subject.

I spoke with Ferrari of Atlanta service and they confirmed Ferrari themself have changed the interval of timing belt changes to 5 years.

 

No insult intended Jim but until Ferrari issues an updated service bulletin the info is just hear say and probably the opinion of the person you spoke with.

 

Correct. 12 years ago on some models.

 

Thanks Brian. Your confirmation is good enough for me.

 

Brian said “some models.” But not the 360 last I heard. The change to 5 years mainly involved v-12 models. And of course, you are welcome to disagree and use whatever interval you want; it’s your car.


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I don’t care to agree or disagree with anyone. I was just posting information that was provided to me from a FoA. Take it or leave it, that’s all.

 

Sorry. I didn’t mean to sound snarky.


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Mass per unit length is a variable, but I tend to agree that the main constituent component of a belts construction that carries tension is a low percentage of the unit weight and even then the various materials that are used also do not differ much in unit weight.

Sure steel and nylon strings can achieve the same frequency, but that doesn't mean the tension in each is the same. Large mass difference between steel and nylon.

T = 4 ∙ m ∙ l2 ∙ fn2

Where:

T is the tension, in newtons

m is the mass per unit length, in kilograms per meter

l is the belt span, in meters

fn is the natural frequency, in hertz

 

Yes, you are correct but belts as a whole don't use either of these. Plus, given the similarity of the materials they do use, by the time you build a belt with all of the rubber etc. the difference in mass is small enough to have minimal impact. I was using the string example to simplify this to be easily understood by non-engineers. I remember a few of these very deep rat holes we got into with non-engineers. For the most part, you can't get them over the hurdles because they just don't have the knowledge base needed and refuse to accept the reality of what you are saying.