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The engine will be fine, it just got some "extra" lubrication.(failed AOS). Like I said earlier, if had the money from all the m96 engines that were replaced due to scenarios just like this, my retirement would be much happier with a few 2019 GT3's in my basement.
If fact, OP of my car had the AOS failed and hydrolocked the car. Dealership replaced the engine.
Bill, I have no knowledge to help but definitely hoping for the best case for scenario for you!
If you replace the AOS, and fire it up, it'll smoke like hell... If you hear any banging noises, you know that you have a bent rod. That's because the piston is being held at an angle.
If you replace the AOS, and fire it up, it'll smoke like hell... If you hear any banging noises, you know that you have a bent rod. That's because the piston is being held at an angle.
Could you scope #4 and see if the piston isn't sitting right, or rocking at TDC?
Lots of times the bent rod isn't that apparent.. It will usually only bend a few thousandths of an inch, and usually the rod bends both directions, and appears to be straight.
This is normal, and expected.. It can't be seen easily.
I'll post a pic later from the other extreme, that can't be missed.
Looking through a borescope or from the sump usually doesn’t reveal the bent connecting rod. Most often, the rod is only slightly bent and you would have to remove it to see this.
No need to get worked up over bent rods imo - all points to a simple AOS failure? Since Bill said he turned off the engine himself - meaning it hadn't hydro-locked on oil yet - and hasn't started it after, there's no chance of him having gotten a bent rod in this case.
When an engine hydrolocks, it's going to be obvious - and you're not the one that stops the engine, in that case.
No need to get worked up over bent rods imo - all points to a simple AOS failure? Since Bill said he turned off the engine himself - meaning it hadn't hydro-locked on oil yet - and hasn't started it after, there's no chance of him having gotten a bent rod in this case.
When an engine hydrolocks, it's going to be obvious - and you're not the one that stops the engine, in that case.
Bill said he hydrolocked it on the starter. The starter can produce a lot of torque, especially the way it's geared, but I am hopeful for bill that it didn't bend the rod.
Bill said he hydrolocked it on the starter. The starter can produce a lot of torque, especially the way it's geared, but I am hopeful for bill that it didn't bend the rod.
He said it wouldn't turn over, after he let it sit for a while so the cylinder filled with oil. If no proper momentum built before it locked, I highly doubt any damage occured to his rods. Just the torque of the starter (even through that gearing) won't bend connecting rods, they're not made of cooked spaghetti. To put it in perspective, a starter motor on a weak battery has barely enough torque to make it through compression of just air, so the resistance of just that air is almost enough to counteract a weak starter motor. Enter hydrolock and a starter on a normal battery, doesn't suddenly make it capable of bending solid forged metal.
The pictures Jake is showing you are the result of forces from a running, revving engine encountering sudden hydrolock.
He said it wouldn't turn over, after he let it sit for a while so the cylinder filled with oil. If no proper momentum built before it locked, I highly doubt any damage occured to his rods. Just the torque of the starter (even through that gearing) won't bend connecting rods, they're not made of cooked spaghetti. To put it in perspective, a starter motor on a weak battery has barely enough torque to make it through compression of just air, so the resistance of just that air is almost enough to counteract a weak starter motor. Enter hydrolock and a starter on a normal battery, doesn't suddenly make it capable of bending solid forged metal.
The pictures Jake is showing you are the result of forces from a running, revving engine encountering sudden hydrolock.
I have seen an M96 engine bend a rod while in the starter, after hydrolock. First hand experience there, and was there when the tow truck driver did it. In the middle of the beam these rods are very weak.
More than likely Bill hasn’t had this happen, but it’s worth noting so he can watch for it.
The bent rod I posted ventilated the top of the block, it did a lot more than score the bore. That one failed on a street with a 35 mph limit with a tiptronic trans and a female driver in her 50s... The planets aligned..
How exactly do you see a rod bend on the starter after it hydro-locked? Same situation as Bill, AOS but shut-off before hydro-lock, or did the engine stall on the hydrolock itself? Or did that particular engine gain momentum for half a turn before locking?
It's a tough sell to my engineering heart. These rods withstand mild engine detonation at high RPM without bending, but are 'very weak' vs. the starter motor? I'll see if I can do a Fermi calculation on the order-of-magnitude of the force the starter-motor can deliver to the rod. Maybe if the stars aligned and the cylinder was hydro-locked exactly at <1 degree BTDC for maximum leverage of the crankshaft.
04-09-2019 | 09:13 AM
