Engine failure

jbrown

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I'm still misunderstanding something here. There is no way an engine with broken connecting rods will run. We must be talking about something else being broken that isn't usually referred to as rods.
 

gv550

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Issues with language and terminology, a few photos would go a long way towards better understanding. At this point I think the flyweights (elephant ears) on the crankshaft were wobbling and resulted in bent or broken crankpin(s) under the rod bearing(s). The engine will still run but would be rattling and generating shrapnel as the rod bearing gets chewed away and likely the flyweights whacking away at the crankcase. The combustion chamber would be unharmed (as noted) but the bottom end would be destroyed. I have heard a large diesel engine run that had a broken crankpin, rattled like crazy and actually still made good power, a lot of amazed mechanics when the crankshaft came out in two pieces!
 
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WJBertrand

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Why I had the crank on my road king trued and welded
I think that makes sense for a Harley as I believe they still use multipiece pressed together crankshafts? Older four cylinder Japanese bikes also had build up cranks. This was because they used lower con rod end and main rolling element bearings, which you can't split like plain bearings. Split plain bearings allow the use of one-piece forged/cast crankshafts. This is the design the for the Super Tenere (and most four stoke bikes today), so welding it's crank would not have the same advantage.
 

Don in Lodi

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Last automotive engine I replaced with seized con-rod bearings was due to no oil. An fyi, there are several models and brands out there where it's "normal" to consume motor oil. Please check your levels once or twice a change cycle.
 

Sierra1

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. . . . An fyi, there are several models and brands out there where it's "normal" to consume motor oil. Please check your levels once or twice a change cycle.
The RT used more when new, than it did with 60K miles. And, even at 60K, it used more than any Japanese bike. The KLR didn't use any, as long as you kept it under 75mph. Above that, it got real thirsty.
 

Don in Lodi

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I've got a Honda Pilot that comes in every 5,000 miles with less than a quart in the pan. The customer absolutely refuses to check it. I've got a Subaru Forester four cylinder that does the same. The burned up motor I mentioned was one of the small Chevy motors.
 

Bill_C

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I've got a Honda Pilot that comes in every 5,000 miles with less than a quart in the pan. The customer absolutely refuses to check it. I've got a Subaru Forester four cylinder that does the same. The burned up motor I mentioned was one of the small Chevy motors.
And here I've been living in blissful ignorance assuming that my days of checking oil level in modern cars were over. I legitimately thought newer engines weren't as susceptible to that anymore... goes to show you not to believe what they tell you at the dealership.

Question Don, is that mostly a high mileage issue or is this true across the board?
Side note, I do check before heading out on a road trip, but not otherwise.

Sent from my SM-G955U using Tapatalk
 

WJBertrand

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I think this is a case by case issue related to engine design and other factors. Some engines are just more likely to consume oil than others. It could also be an assembly or manufacturing issue. If an owner neglects oil changes, uses a substandard air filter and lives in a dusty climate, or runs the engine too hard before it's allowed at least a couple thousand miles to break in, any engine can end up burning oil, sometimes at fairly low mileage.
 

Sierra1

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I think this is a case by case issue related to engine design and other factors. Some engines are just more likely to consume oil than others. It could also be an assembly or manufacturing issue. If an owner neglects oil changes, uses a substandard air filter and lives in a dusty climate, or runs the engine too hard before it's allowed at least a couple thousand miles to break in, any engine can end up burning oil, sometimes at fairly low mileage.
You're correct, there's no way to tell until you've had the vehicle long enough to get a feel. That being said, I can't remember the last time that I had to add oil between changes. And, nowadays, the oil comes out much cleaner than "back in the day".
 

WJBertrand

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I've owned a few oil burners. Not severe, but enough that I needed to keep an eye on it. My old '84 Toyota pickup started to use oil after several years use of a K&N filter. The same happened to my '93 ST1100, also after using a K&N filter for a number of years. Could have been a coincidence but I've lost any confidence in K&N as a result. My previous ST1300, current '15 Super Tenere, '11 Toyota Rav4 and '13 Mustang GT don't use any measurable oil between changes. Always used OEM style air filters in all of them. My 2002 Lexus started to use a little bit of oil around 100,000 miles, less than 1/2 qt. between 5000 mile change intervals. So it seems almost any kind of an engine can become an oil burner, sometimes for no apparent reason.
 
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ballisticexchris

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There is no way an engine with broken connecting rods will run
Actually an engine will still run with a broken rod. My KZ 750 spit out a rod on the freeway and still ran on three cylinders until I pulled into the station and shut it off. Even when I got it home it started right up. I was scratching my head at that one. I rode with the rod knock for hundreds of miles before it finally let go.
 

lund

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I've seen more then one engine with major catastrophic breakage run.
Seen them with broken in half crank, sheared wrist pin, hole in block from rod, seizure from overheating and including broken rod. Its not always the case but not impossible.
 
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