Engine designs that have problems 22

[enginesrus]

Since the one thread I started, is headed way off topic, reason for this.
Engine designs that have problems or have had them.
I'll start with the 3 valve Triton.
This guy explains. Has data from others that deal with the same problems.

https://www.youtube.com/watch?v=xcN_WcGr4BU

 

[GregLocock]

"I see no reason for the average vehicle to have to weigh in at close to 2 tons'

Guess what. The only people who car manufacturers listen to are the ones who buy new cars, and the legislators.

30 years ago we made a car with 6 seats, weighed 1418 kg, got around 20 mpgUS, had a 160 hp engine and a manual 5 speed. It had an AM/FM radio with a cassette player and 2 speakers

When we introduced the final model in 2014 it weighed 1704 kg, had only 5 seats (crash) airbags(crash) auto only (customer preference) full climate control (customer preference) dual cats (legislation), got 24 mpgUS, IRS, much bigger (heavier) wheels and tires, ABS, TC, ESC, full audio with 9 speakers including a subwoofer, electric windows, electric seats, met stiffer emissions and crash regs, 261 hp engine (actually the same one). It was faster, quieter, rode better and is more durable.

Now we didn't put that stuff in for fun, we did it because the people who buy new cars wanted that stuff and were prepared to pay for it.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[enginesrus]

Back on topic.
BMW engines and their bearing failure problems, and timing chain guides and oil pump drive chain failures.
How many Engines can we list with these sort of problems?

 

[enginesrus]

The Porsche engine recall about a year ago? Possible cracked connecting rods? I would like to know what they are made from? Are they PM?

 

[SwinnyGG]

Back on topic.
BMW engines and their bearing failure problems, and timing chain guides and oil pump drive chain failures.
How many Engines can we list with these sort of problems?

We were on topic, but I digress.

Where's the data?

The Porsche engine recall about a year ago? Possible cracked connecting rods? I would like to know what they are made from? Are they PM?

Ooo. For this one, we actually have data. This one affected me directly - I know the situation well. The recall was issued after an issue was found with a particular batch of rods during QC testing at the plant in Zuffenhausen.

Total 718 production for 2021 was 21,250.

Total number of vehicles affected by the connecting rod recall was 190. That's 0.8% for those of you playing along at home.

Of the 190 vehicles affected, only 20 had actually been delivered at the time the recall was issued. That's 0.09%.

Where's the disaster?

 

[TugboatEng]

But what if a Porsche 718 was those 20 people's only means of transportation?

 

[BiPolarMoment]

They will just have to Zoom during the Board of Directors meeting.

 

[CWB1]

Somebody needs to save a few of these posts as an example of how to either get yourself uninvited from DFMEA reviews or into trouble.

Me: Possible effects? Customer dissatisfaction.

Theywhodontwanttobethere: The engine could brick itself causing a reduction in braking force, a loss of control, and a pregnant nun's vehicle going off a bridge, landing on a schoolbus full of kids, and....

 

[TugboatEng]

If they wanted to "Zoom" they should have bought a Mazda.

 

[BiPolarMoment]

Me: Possible effects? Customer dissatisfaction.

So you're saying the Aztec didn't have a row in the DFMEA that included customer perception?

If they wanted to "Zoom" they should have bought a Mazda.

...I've had three; still have one and it's coming up on 25 years old (I've had it for ~16).

 

[wayne440]

...Your average grocery getter family sedan has 0-60 times that rivals that of the muscles cars of the 70’s. Why?...

Because it makes my wife happy. She wanted a Charger and we bought a 3.6 powered model, it later needed minor repair and the loaner was a 5.7 - the moment she started it up I knew it would end up hers. And if she asks for a 6.4 or a Hellcat, she will get it.

 

[enginesrus]

So what material are or were the connecting rods made from? Its just not normal for new connecting rods to have that sort of problem. And yes if the engine would have locked up on a congested freeway at the speed limit it could be a potential disaster. What other engine makes in road vehicles have had flawed connecting rods in the past? I can't think of any, bearing problems yes.
I read that Porsche was using PM to make crankshafts, is that true? If so then the rods must be sintered as well, and would fully explain the problem.

 

[TugboatEng]

GM has been using sintered rods for nearly 3 decades. That is not a root cause of the Porsche problem.

 

[SwinnyGG]

Its just not normal for new connecting rods to have that sort of problem. And yes if the engine would have locked up on a congested freeway at the speed limit it could be a potential disaster.

This subforum is 'engineering failures and disasters', not 'things which happened which had a small probability of resulting in property damage if they hadn't been caught during QC processes and properly addressed by the manufacturer before reaching the market in significant quantities'

 

[CWB1]

Its just not normal for new connecting rods to have that sort of problem.

Everything has "that" problem, its called quality issues. We're manufacturing far more parts with far more complexity, with far fewer people, and doing so at a rate far faster than ever before. Even with ever-evolving QAQC crap happens and bad parts slip through accidentally. Occasionally vehicles are built with "bad" parts bc delaying sales is more costly than a warranty repair for minor issues. If issues didn't arise then OSHA and insurance companies wouldn't require hard hats and steel toes on plant floors. On the brighter side, for most every issue there's a severely underappreciated miracle of modern manufacturing.

 

[LionelHutz]

I'm also still waiting to read about any actual disasters in this thread.

A few bad connecting rods is the best you can produce? Big deal.

 

[GregLocock]

I'll tell you a manufacturing one. Started to get field reports of crank position sensors being destroyed on high mileage cars. The CPS reads a tonewheel on the engine side of the front pulley.

Problem engines bought in, noticed that the cranks were slopping forwards and backwards, hence ramming the pulley into the CPS.

Looked at the thrust washer, and the crank was worn away, allowing the motion.

By this time practically the whole engine section was involved to some extent, obviously with the engine lab taking the lead.

So they did an Is/Is not, and identified the time period when the problem started.

Back over to the factory, found that the lapping machine had been refurbished at that date. For some reason they had reversed the direction it lapped in, and the new direction increased the wear rate.

Cheers

Greg Locock


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[XR250]

I have owned three vehicle with gear driven cams:

1987 Honda CB1 motorcycle
1998 Honda VFR800 motorcycle
1987 Subaru BRAT

 

[enginesrus]

Then there was the major problems with sludge formation, in many different brands of automobile engines.

 

[enginesrus]

From the 1950's into the 70's, there were not many engine design failures, they were battling cam and tappet wear, and sludging in the 50's. Leaded fuel was not a huge help for engine durability in those days.
The choice from large recip aircraft engine manufactures, to use flammable magnesium castings for nose, accessory, and diffuser cases was a disaster waiting to happen, and many lives were lost because of it.

 

[Lou Scannon]

echo...echo...echo...

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz