Auto stop benefit

[Plati]

I know myself, I have 2 Expeditions.

A 2014 without ASS and other gooblygook electronic whizbang features with an old style V8 (no turbo) where I disabled the rear hatch lift motor since to me its justanother thing to break. I use this mainly for cross country travel or 30 minute trips or to impress a hot chick from Pittsford on a date. This vehicle use is optimized for long term reliability.

A 2003 BEATER that I use locally for all the short trips and to let it pickle in the salt bath environment all winter (which shows). I like the fact that this one is started and run for several short trips every day and I can preserve GrandPappy for 2030. In other words, less starts is more smarts for GrandPappy in my fleet. I also use this vehicle when I'm going on a date with the even hotter chick from the trailer park, and we go 4 wheelin on the way home, roll in the mud, etc.. So I agree with the "start = wear" philosophy.

FWIW … I'm not trashing the whizbang features, just not for me. It is America after all!!

 

[Calidad]

If you ever have done a safari they never idle their tour trucks. And they use old tech. The 9 passenger tour rig we had was 4 yrs old and had 140,000 miles on it (converted from KM) The owner operator told me his old truck was still on its original starter. I did ask given he shuts down before you stop rolling.

I wouldn’t worry about it. As for shut down in my region we can have long stop light waits which case shut down doesn’t bother me. Stop and go traffic I shut it off given it will shut down and restart unnecessary too much etc.

If you live in the wide open yeah I could see it being of no value. Except that the largest car market in the US isn’t in open plains states so Auto makers do whats wanted in the top markets.

 

[sjwhiteley]

The only other thing I’ll add is Ford does not use Auto/Start Stop on the Super Duty line where maximum reliability is their chief priority. I think they would have used it if it did not compromise anything, but because F-250 is not effected by the cafe standards it is not used. I’d argue this start stop is cafe standard driven. Anyway I will stop hammering on this technology now and don’t wish to derail the thread.

I do not think this is a thread derail...it’s directly related to as/s benefits - and drawbacks.

I use it - or rather, don’t bother to turn it off - but it’s based on the driving I do where I am. The traffic lights seem to be chronically long. The annoyance I have is parking: stop the car in the parking spot, engine stops, then shift to park and it immediately turns on, again.

 

[Wangle]

The ASS doesn’t start the engine when it’s cold or when it ‘has no oil’. The engine is barely depressurized in most ASS starts and if the temp drops it starts up again.

Beyond that bearings are of a stronger material than they used to be as is the starter...not to mention higher tolerances and oil with higher levels of lubricants.

Unless you altered your expy that is how it works.

The ASS doesn’t start the engine when it’s cold or when it ‘has no oil’. The engine is barely depressurized in most ASS starts and if the temp drops it starts up again.

Beyond that bearings are of a stronger material than they used to be as is the starter...not to mention higher tolerances and oil with higher levels of lubricants.

Unless you altered your expy that is how it works.

“Barely depressurized” = depressurized = no oil. Is it as bad as it cold start? Of course not. Is it not pressurized for some period of time after it was shut down? Of course. Is this damaging to the engine? There is no evidence pro or con, and I choose not to take the risk. If I am wrong, I spent a few bucks more on gas. If I am right, I avoid a starter replacement and/or an engine problem. And by the way, the engine bearings are the same, only the starter bearings have been beefed up.

 

[carymccarr]

“Barely depressurized” = depressurized = no oil.

Again. No. Incorrect.


“Not only are the engines at operating temperature before the stop/start system begins to work, the vehicles also use electric water pumps to maintain optimal engine temperature when they’re stopped. If the engine is off long enough to reduce engine temperature significantly, the engine will automatically restart.

Secondly, while the engine’s oiling system isn’t completely pressurized as it when it’s running, the oil in the passages hasn’t been allowed to completely run down into the oil pan.”

 

[Wangle]

Again. No. Incorrect.

I would let this go, but your ignorance is confusing people. When an engine is shut off the oil pump stops. Oil drains back into the pan, pressure drops to zero. Some residual oil is left on the lubricating surfaces, and diminishes over time. Even a few seconds reduces the oil film protecting these areas. When started again it takes a certain amount of time, perhaps 1-2 seconds, for oil to be pumped back to all surfaces, and pressure returns to normal. This WILL cause extra wear. How much more is the debate. I hope this helps clear things up.

 

[carymccarr]

I would let this go, but your ignorance is confusing people. When an engine is shut off the oil pump stops. Oil drains back into the pan, pressure drops to zero. Some residual oil is left on the lubricating surfaces, and diminishes over time. Even a few seconds reduces the oil film protecting these areas. When started again it takes a certain amount of time, perhaps 1-2 seconds, for oil to be pumped back to all surfaces, and pressure returns to normal. This WILL cause extra wear. How much more is the debate. I hope this helps clear things up.

No.

“Not only are the engines at operating temperature before the stop/start system begins to work, the vehicles also use electric water pumps to maintain optimal engine temperature when they’re stopped. If the engine is off long enough to reduce engine temperature significantly, the engine will automatically restart.

Secondly, while the engine’s oiling system isn’t completely pressurized as it when it’s running, the oil in the passages hasn’t been allowed to completely run down into the oil pan.”

So it’s probably fair to say yes, sure, ASS adds some wear/tear to the engine. Is it more than hammering the gas to WOT once a week? Or only driving short trips? Who knows. But I have yet to find a reliable source who can say it adds any level of material wear.

 

[Deadman]

The reality is the most concentrated and quickly compounded engine wear is on cold and warm starts and remains to be so on AS/S vehicles. Oil companies and engine rebuilders have spent millions on research and have good reads available, they know their stuff and tear these engines down. Something these AS/S advocates don’t generally do, now I’m not saying as/s has no benefit fleet wide it does save fuel but it also increases wear. As the oil pump supplies and the crankshaft spins the oil fills the space between the journals and bearings, it floats in the oil film and doesn’t directly contact the bearings, this is hydrodynamic lubrication. Stopping the engine halts this process and the film the crank is floating in thins out and conforms to the roughness in the metallic part. This is boundary lubrication and at this point the peaks in the surface make contact with the bearings increasing wear to them when the crank begins to spin again on start up. Some manufacturers have a coating on the bearings to try and alleviate this but, but I don’t find any evidence Ford uses this coating on their cranks like the high performance imports do.

If one chooses to inform themselves on the wear portion from sources that aren’t in the business of lubrication or engine rebuilding (which relate to this increased wear) they are misinformed. Again AS/S does save fuel and has many benefits for fleets I’m not arguing that. Not to mention environmental benefits. But it also has many disadvantages when in use. Don’t blindly put faith in the engineers who couldn’t fit an oil pump rated for the job in mod motors or design a variable timing system that doesn’t break down fast. I’m just saying to think critically about the issue.

Anyone that thinks these systems are looking out for us is wrong. They are just trying to meet EPA numbers and they could care less if the crank bearings fail on us at 200K!

 

[aggiegrad05]

Anyone that thinks these systems are looking out for us is wrong. They are just trying to meet EPA numbers and they could care less if the crank bearings fail on us at 200K!

Good lord I hope I'm not still driving this same car in 200k miles. I mean, I love it but yikes that's a long time.

 

[JExpedition07]

Vehicles should be able to last at least through that mileage though. I’ve seen a few videos with powertrain engineers talking about design life, you’d be surprised at least in the HD pickup trucks how many miles they are designed to hit. Almost half a million in some cases.