355 cam belt problem

Did the dealer replace the tensioner bearings during the major service?

 

This is a direct result of not following propper tension procedure, as outlined in the 355 workshop manual. When they pull it apart, my guess is you will find a fully extented hydraulic tensioner. I have seen this before, and the result was not pretty.

 

For the purposes of this discussion it matters not if the bearings were replaced. I only say that because if it was a bearing failure we would be talking about a blown up motor and not a slipped belt.

The 355 hydrostatic tensioner is a built in fail safe device, if and only if, the tension is correctly set in the first place. If that is the case it is almost impossible for the belt to slip. Tom is correct, someone at the dealer screwed up.

Unless they can prove some foreign object got in and caused it to slip (very long story but I have seen it happen) they really have no defense. The evidence can be destroyed within seconds after removing the belt cover so if you have any reason to doubt their veracity I would want an independant witness of the removal that is familiar with working on the belt drive system of the 355.

 

P.S.

Whatever you do, do not run the motor again until it is taken down to be repaired. It sounds as though the belt has not slipped enough to cause valves to be bent but if it slipped once there is no reason it cannot slip again and do very expensive damage.

At that point you would have a very large bill to be contesting and it would serve no purpose.

 

It's a remote possibility, but cam timing can jump in the event of the car spinning while in a forward gear, and travelling backwards with the engine turning backwards as clutch not pressed. The fully floating nature of 355/360 tensioners makes them particularly vulnerable for this.

I've seen a few Ferrari belts with foreign matter entering... there is usually some sign.. I've seen three separate cars with little "trap doors" in their belts, where a stone or whatever has gone physically through the belt. This doesn't always mean the timing will be moved though.

 

Well you guys know I'm the first guy to cry foul on pro mechanics who take short cuts or who do not know what is going on. However, while the pros here are probably right bad install...sh*t happens. After 10 months of driving under unknown conditions no mechanic could or would guarantee such work. In fact the 355 uses a dual belt system and arguably the acused mechanic could just as much say "I did both belts the same way and see the other one is just fine...so it's not my fault". We also do not know under what conditions the mechanic worked. Sometimes you get a guy who comes in and the first thing he says is I love this car but it costs me an arm and let, I get no sex from my wife because I spend too much money on my Ferrari and pretty soon the mechanic thinking he is doing a guy a favor when he knows that by the book new tensioners may be needed. OTOH, the phone could have rung and he forgot to tension one side and the guy was lucky for 10 months because Ferraris can take an amazing amount of abuse. I think it is a tough case to prove. The funny thing about this as the pros on this list will attest...there are bad mechanics out there than customers love. They screw the car up and take it to the bad mechanic who fixes it wrong and when the car comes back they make more money charging more and say "hey its a Ferrari." There are a surprising number of people who accept this. A charismatic mechanic can get a long way even if he sucks.

 

it's one of my pet hates. unscrupulous mechanics have caused more people to sell their ferraris than any other reason, i reckon. Mechanics can make ferrari ownership extremely painful.

personally, i never let them get away with anything...but other people lack the knowledge and the time to do anything about it.

 

Now that's really good... except that you are missing an extra "R" LOL!

I am curious, though, about the comment made by Ferrarifixer: "It's a remote possibility, but cam timing can jump in the event of the car spinning while in a forward gear, and travelling backwards with the engine turning backwards as clutch not pressed. The fully floating nature of 355/360 tensioners makes them particularly vulnerable for this."

We all know (or are supposed to know) that in the event of a spin, say at the track, the rule of thumb is to depress brake AND clutch, to prevent engine damage as the car travels in the reverse direction with a forward gear engaged. That works with a normal 6-speed. How does this work with the F1 system? Does the computer detect a condition like this, and react fast enough to disengage the clutch and put the car in neutral? It does this automatically as the car comes to a stop, but things are happening a lot faster in a spin. Does anybody have any experience with this? It would be nice to know what the system does in the event of a spin.

Good luck, Russell, with your predicament. I hope the resolution goes in your favor.

Regards, Alex

 

Not sure what you mean about the extra "R"...

But anyway, 360C definitely have the software to detect a spin and disengage clutch, and I assume that road cars do, but I can't say anything about 355F1 with any surety.

 

You have been advised wrong.

If the belts were correctly installed the hydrostatic tensioner provides a fail safe like I said earlier. A belt whiplash cannot occur and electronic gizmo (I use one too) or not it can be done wrong and allow this to happen. If it was done correctly this cannot happen.

A spin causing a sudden very rapid reversal of the engine is about the only way this can happen unless the job was done improperly.

If that was not the case we would experience it on a regular basis.

 

Isn't that the truth!!!!

 

"Anything designed to have a tensioner fitted to it's "slack" side will have inherent dangers when run backwards".

Hi phil, I would have thought the hydraulic style tensioners on the 355 and 360 would allow the engine to rotate counter clockwise without changing the tension on the belt. I have seen what happens to mech. style belt tension on the 308-348 when you rotate the crankshaft ccw the belt loses its set tension but, I didn't get that same result when I was playing around with my 355(during a belt job) the hydraulic tension seemed not to be effected. The hyd. tensioner appeared to absorb and readjust the belt. Albeit I wasn't applying a shock to the system, ie; by a spin, just turning the engine over by hand(wrench applied to the crank nut). Correct me if I am wrong just trying to understand logic of this. Regards, Vern

 

The hydraulic tensioner will compress when/if the engine runs backwards. It is damped, but it only takes a second or so under high pressure. Once the tensioner is fully retracted, the backwards running belt is free to "whip" or "ripple" on the long side and jump a tooth quite easily.

 

I would think the dealer would stand by their work for at least 12 months...I know my dealer FoA does;and I am confident that they would in a case such as yours. I would send them a detailed letter letting them know what you expect and as well as request a meeting with the owner. Further, I disagree with the other posts that you could not prove that faulty workmanship is to blame. While it would be your burden in a legal case, without either faulty installation or a particular parts failure, cam belts do not slip. If the dealer will not make the repair for free, I would have it done elsewhere and sue them in Magistrate Court for what you have to pay to get the work done...while they will likely reimburse you rather than defend in court, if they do not, you will likely win anyway...you will need to get the mechanic that you have to pay to do the repair go to court with you to testify though...Good Luck.

 

Hi Russell, Ferrari makes a belt guard for the 355 Challenge cars that in a sense plugs a hole in the lower belt cover area that would stop a small stone from entering the timing covers which is probably where the stone entered. I don't think the road cars came with this but is on the challenge engine. The part no. is 174690 it could be installed after they have your car back together. Another question for you, are all of your underbody panels in place and also all the inner rear fender/wing panels in place? They help keep rocks/stones out of the engine compartment Regards, Vern

P.S. You were lucky you could have been looking at a top end rebuild for about 4X that.