1199 Sudden Engine Vibration on track...

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SirJAG said:
@SuperDomestique ya man...almost 20K miles on the 1299 now...during the last desmo had the tech take pictures with scope of both piston heads, and valves...everything looks good so far, fingers crossed!
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Sounds like a bottom end problem more than anything. Like excessive/premature bearing wear (like BMW S55/65 engines) or inadequate con rod strength (like on McLaren 720). In either case, it’s a matter of when not if things are going to take a .....

If it’s bearing wear, I’m thinking frequent oil changes and letting the engine warm up properly will slow the wear. If it’s crappy con rods, it’s either replace with better ones or keep the revs down.

Unfortunately, to do preventative maintenance requires splitting the engine which is so dumb. It’s like they designed the engines not to be easily serviceable.
 
Like easily checking at least rod bearings and replacing as needed. On car engines, you just drop the oil pan. Not on a Duc. Removing the oil pan will only get you into the gearbox. This is the access you get on a V4 motor.

IMG_0070.jpeg
 
I wouldn’t consider checking bearings preventative maintence. When was the last time you dropped an oil pan to check bearings?
 
bp_SFV4 said:
I wouldn’t consider checking bearings preventative maintence. When was the last time you dropped an oil pan to check bearings?
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Having easy access might and the ability to easily change bearings would probably prevent a lot of these grenaded engines. It’s like the BMW motor problem. Initially it wasn’t a thing but now it’s considered routine maintenance
 
Considered by whom?

You never read about all the bikes that didn’t spin a bearing. I think you are putting too much weight on the failures.
 
bp_SFV4 said:
Considered by whom?

You never read about all the bikes that didn’t spin a bearing. I think you are putting too much weight on the failures.
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Nah dog. If you track your V4, it's bound to fail. Like I said before, it's not a matter of IF it will detonate, it's WHEN. Riding it easier just prolongs the inevitability. Just look at the V4 race schedule maintenance. For the normal V4, a complete engine refresh is every 3k mi. On the V4R, it's 1500 mi. The serviceability could be improved.
 
IDK, 3,000 track miles isn’t insignificant, especially if you’re actually racing not just having fun on a track day.
 
Yeah, but I don't think the racing schedule applies to track days. I mean, maybe if you're winning in A group, but that's not most track riders. It's great the valve train can keep up with the high RPM, but the lower end doesn't seem to be quite as able. I think this is the reason the R has a more severe schedule as it revs higher. I also don't know how much this deviates from other brands.

The Ducati engine builder which came up in another thread, @craig bush mentioned him, has a blurb on his site saying when they blueprint a Ducati engine they use Corse spec tolerances which are actually looser, making spinning a bearing less likely. The same builder said 5k track miles was all he expected out of one of these engines which seems to be in line with Craig's experience.

IIRC, Craig got to 5k before his V4 detonated, but he didn't take a bike with a failing water pump to the track. If spinning a bearing in the bottom end is the death knell of the V4, mitigating heat and keeping it well oiled is the priority.
 
bp_SFV4 said:
Yeah, but I don't think the racing schedule applies to track days. I mean, maybe if you're winning in A group, but that's not most track riders. It's great the valve train can keep up with the high RPM, but the lower end doesn't seem to be quite as able. I think this is the reason the R has a more severe schedule as it revs higher. I also don't know how much this deviates from other brands.

The Ducati engine builder which came up in another thread, @craig bush mentioned him, has a blurb on his site saying when they blueprint a Ducati engine they use Corse spec tolerances which are actually looser, making spinning a bearing less likely. The same builder said 5k track miles was all he expected out of one of these engines which seems to be in line with Craig's experience.

IIRC, Craig got to 5k before his V4 detonated, but he didn't take a bike with a failing water pump to the track. If spinning a bearing in the bottom end is the death knell of the V4, mitigating heat and keeping it well oiled is the priority.
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Yep, that’s what Mark Sutton @ DucShop said.

@SuperDomestique is correct regarding rod bearing inspection - in the performance car community, it is fairly common to pull the oil pan to inspect rod bearings. Happens in the supra community (turbo 3L making 2-300 hp/liter) often - every year preventively if you’re running the car hard (drag racing or half-mile runway events). And definitely as soon as you hear what might be rod knock as in this case - rpm dependent knocking is rod knock until proven otherwise afaic’d (I’ve lost a supra motor and a pv4 motor to a sound bearing). Bearings should have been inspected. I’m surprised the motor lasted another lap.
 
bp_SFV4 said:
In your case wasn’t it a main bearing that failed? Was it the same one that the OP has pictured?
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We think it was the rod bearing that failed - bearing looked like it got really hot and the rod was broken. It’s my understanding that rod bearing failure is more common, and main bearing failure doesn’t break the rod as often.

The reason rod bearing failure causes knock is because as it fails the clearance opens and the rod big end starts to wobble on the crank journal with each direction change - “rod knock” (rpm dependent obviously, so it gets louder and faster with revs).

It’s also my understanding that as the rod bearing fails and the oil is contaminated with bearing material, it can cause main bearing failure secondarily. So while you might see both rod and main bearing damage, it’s usually the rod bearing that failed first.

Catastrophic motor failure (seizing and high-siding or splitting the cases and oiling the track) is definitely a risk with a spun bearing. No vehicle making an rpm dependent knocking noise should be driven until rod knock has been reasonably ruled out. If you choose to risk it and you oil down the track when the motor grenades, you should expect being labeled “that guy” that ruined everyone else’s session, and if it caused accidents…
 
craig bush said:
We think it was the rod bearing that failed - bearing looked like it got really hot and the rod was broken. It’s my understanding that rod bearing failure is more common, and main bearing failure doesn’t break the rod as often.

The reason rod bearing failure causes knock is because as it fails the clearance opens and the rod big end starts to wobble on the crank journal with each direction change - “rod knock” (rpm dependent obviously, so it gets louder and faster with revs).

It’s also my understanding that as the rod bearing fails and the oil is contaminated with bearing material, it can cause main bearing failure secondarily. So while you might see both rod and main bearing damage, it’s usually the rod bearing that failed first.

Catastrophic motor failure (seizing and high-siding or splitting the cases and oiling the track) is definitely a risk with a spun bearing. No vehicle making an rpm dependent knocking noise should be driven until rod knock has been reasonably ruled out. If you choose to risk it and you oil down the track when the motor grenades, you should expect being labeled “that guy” that ruined everyone else’s session, and if it caused accidents…
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Rod knock that has been identified and not thrashed has a high likelihood of being fixed. Like if you hear/feel the knock at idle shut the engine down and fix it. Don’t keep riding it thinking it’ll be all good. It’s only when you stress the motor do things go south.
 
@SuperDomestique do you have theory on my failure? did you see them pics? I didnt have a knock that i could hear until that final ride...and when i tore the motor apart the rods and bearings and whole bottom end looked great..... (sorry to hyjack OP)

JAG
 
SirJAG said:
@SuperDomestique do you have theory on my failure? did you see them pics? I didnt have a knock that i could hear until that final ride...and when i tore the motor apart the rods and bearings and whole bottom end looked great..... (sorry to hyjack OP)

JAG
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Tough to tell. I saw the rod and the surface looked ok visually. And if you’re saying the shells look good, then most likely it wasn’t the bearings. Valves also looked ok at least on the superficial head portion. If the stems look good and straight it wasn’t a timing issue. The piston has that spot where it's worn out or chunked. But something metallic was pinging around your cylinders. I’ve heard in other engines about piston squirters sometimes loosening or a screws loosening into the oil pump assembly. The weird thing is that crankcase became pressurized and dumped oil into the airbox. Any mods to the bike? Did it still have the PCV system? Someone in your post mentioned piston ring failure but you'd expect maybe some smoke as a tell-tale sign and not sudden catastrophic failure. But then again I'm no expert
 

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