348 Engine blew 367 days after last major...

That would be very strange unless the cam seized


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I just spent tons of time reading this thread only to find out this probably never happened. Everyone asked for photos and info and a year + later none provided. (stay tuned) LOL

 

And what was the cause of the belt failure? I don't think it was Gremlins.

 

Ohh no, it happened.

 

Here is what I think happened. Engine threw a shim (still no cause of that), that cam seize or stopped spinning in a fortunate spot, belt teeth teeth then sheared, other side cam bank hit valves. Walla.

 

Maybe the mice ate it

 

As I said last time, I don't believe that fantasy for a second. They dont "throw" shims. I'd sooner believe Elvis was taken by aliens.

 

Yes, and picture of the damage prior to disassembly would really help. Would be something to see a shim cocked out of the bucket wedged between a lobe and head. Without that there is something else going on in the damage cause report that is dubious for reasons one can only ponder. Damage on 1 side is rather strange is not unheard of.

 

348 lives matter! Dam this cancel couture.

 

lol I read a guy in the Tri State regional forums going on about how he spends 1.2mm a year at Classic coach and the service is amazing and wants to argue with anyone about that. Yes, it's called service differentiation. Its not about the car, its about the wallet, take a 348 and a Daytona in for a body off restoration and throw in an F40 for engine rebuild at the same time and watch how much better service gets. That's literally what's in there.

I can't even get a quote for a carpet replacement, zero interest. If I did back them into it the car would sit for god knows how long.

 

Well considering I have been working on Ferraris since almost the beginning of the shimmed type valves and I have never seen it or heard of it happening to one of these engines strongly suggests it didn't happen here. Having seen many of these motors run at well over 10,000 rpm and being in them when they had valves float also strongly suggests it doesnt happen.

Damage on one side is not in the least unheard of.

Maybe a little better understanding of how all this works is in order.

 

At a dealer or an upholstery shop?

 

At the swanky Indy shop that does restorations... where this car is.

Interesting to hear when a belt breaks while engine is spinning it can piston interfere one side only, not clear how unless one bank of cams cam stops spinning/seizes. Perhaps enlighten me beyond that scenario. Be appreciated.

Had 2 motors that happened to both sides, clink, clink, clink.

 

348 only has one belt. We were told it was striped of teeth. How many? Typically one small area but we don't know. We also dont know which valves were bent. The 4 valve engines due to the small amount of lift and the small valves and the valve angles need to be nearly wide open to be hit by the pistons. There are many positions the cams can stop and have that happen. The problem with arm chair diagnosis, we have very incomplete and probably inaccurate information. .

You had 2 Ferrari motors spit out shims? Several hundred miles after last adjustment?

 

With a stripped belt the cams all typically stop when the damaged part of the belt gets to the drive pulley. A very small window for piston valve contact when you take my comments above into consideration. More than once I have seen 4 valve Ferrari motors assembled with all 4 cams in the wrong position and turned through with no damage. The timing window for contact is actually pretty small. More than just a few bent valves is uncommon. There are a lot of variables. Thats why you really need to have eyes on disassembly to have any chance of knowing what happened.

 

No no, I was not clear... one was a Subaru JDM STi Spec C 9000 rpm motor where the shop neglected to tighten down the belt keep to prevent the timing belt from jumping teeth around the drive pully. Skipped decelerating in a parking garage. The other was a failed drive pully on the 348.. Point is I had 2 engines interfere, both mangled both banks, my Ferrari one lost no teeth on the belt btw, the mangled chunk of fence went under the pully what looks like 3 times as it was folded over 3 times.

Great info thanks Brian.

 

I pounded the though of a small section of stripped teeth. If one of the cam seized and the engine initially kept running then unless the cam began to rotate again it would seem teeth would continue to get stripped and the engine could potentially run on one bank until the stripped ares reached the other bank. But I would expect that to result is some damage to the second bank as well. The engine may quit aft that but not until it rotated further, due to its angular momentum. On the other hand, if the teeth stripped at the drive gear all 4 cams would stop and again there could be damage to both sides, depending on RPM at failure.

Owning a 308 QV which suffer a belt failure on one bank and the engine kept running, it suffered only very minor bending of 2 intake and 2 exhaust valves in different cylinders. Barely detectable to the eye without a reference. (thank you low compression ratio ). Barely a thumb nail mark on the pistons. At first I though it was an ignition failure but examining the problem I found a broken belt.

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A lot of "if's". And just as you say, it may be a case of 2 profoundly bent valves and a few more unnoticed and only slightly bent. We dont know. It could also be a case where the belt stripped on the exhaust cam just prior to the drive pulley then stopped at the drive pulley. Again, only the disassembler knows....if he even took notice. All the evidence is in a land fill.

 

So no Ferrari motor in your personal experience ever spit out shims?

And its easy to understand why with that type of failure. Different failures produce different results.

 

Nope I've never had a car spit out or cock a shim I don't even know how it's possible. My old motocross bikes with the same 4v bucket and shim design were 14,000 RPM and never had it happen. It's designed not to do that including over rev and bikes over rev by A LOT and often.

Don't see how it happens but I'm pretty sure that's what he said he was told early in the thread. Perhaps at the end of this and once the car is running he'll have some pics of the failure.

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Proof of Sasquatch or pics of this failure. Either are equally likely.

 

I doubt he ever will. If indeed it happened it didn't happen the way they told him so why provide evidence of their lie.


Some engines have been known to displace shims and in the early days of having the shim on top it was always the argument used why shims on the bottom are superior. It has happened but never once on a Ferrari that anyone knows about.

 

Which jives with his story of tooling down the park way at normal speeds and it all went sideways. No over revving on his part which he was adamant about.

 

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