Cold Start Thickness - Dr. Haas

[ADFD1]

Originally Posted By: Drew2000
Originally Posted By: ADFD1
Originally Posted By: tig1
My sons Ranger couldn't have much wear with the age and miles on it. So with that history there's no way that I can see of proving the advantage goes to 5W oils.


I think the 0W or 5W oil has its real advantage where people make short frequent trips in cold climates. Many of these 300,000 mile cars are driven on nice long runs without frequent cold start stop cycles. When I think back when I lived on Long Island and how winter trips were, stop start, stop start, then sit in traffic. Come to think of it all the trips were like that. When I moved out west I saw how much easier life is for an engine, I bet my cars will last 300,000+ miles and have less than half the wear caused by living in Nassau or Queens.

Front brakes typically lasted 25,000 miles, and I'm easy on a car. I checked brakes recently with 48,000 miles on them and they're still good, I'll have another look in another 10,000 miles. I was shocked.

AD


You hit the nail on the head. Since I started to work in NYC this year, my little SUV gets driven about 2.5 miles each way to the LIRR station, maybe a few longer errands on weekends. Running M1 0w20 now....we'll see.

How do you like WA compared to Nass/Queens? Been out that way a few times both east and west WA, lovely country esp. the Pend Oriele (sp?) area.


Thanks! I briefly worked in Jackson Heights, and made that trip M-F for some 9-5 work. It was extremely hard on the car, I did it for a short period, but could see how 10,000 miles of that would equal about 50,000 miles of my Adirondack Mountain runs.

WA is beautiful, however I liked the Adirondack mountains better. NYS winter road salt sucks! Where I am in WA it doesn't snow much. Comparing WA to Long Island, I'll take WA, because of less congestion, and the people seem more caring and relaxed. The rain you can keep though. Oh yea and its easier on the car.

AD

 

[SpitfireS]

How long does it take for the coolant thermostat to open after a "cold" start?
I'll bet: way less than 20 minutes of driving.
IOW: heat is being removed from the engine instead of it being fed to the engine oil (to reduce cold oil wear)

Solution: get an oil to coolant heat exchanger.

Btw, I'm still sticking to this: at 40C a 55 cSt oil will flow faster through an engine (and pick up more heat) than a 65cSt oil.

 

[demarpaint]

How fast a T-Stat opens varies. Depends on engine design, displacement, and other factors, along with what the block is made of. My 88 E-150 takes a while to get the temp needle into the normal range, the 08 Jeep takes no time at all. The faster an engine gets to operating temps the better.

 

[BuickGN]

Originally Posted By: SpitfireS
How long does it take for the coolant thermostat to open after a "cold" start?
I'll bet: way less than 20 minutes of driving.
IOW: heat is being removed from the engine instead of it being fed to the engine oil (to reduce cold oil wear)

Solution: get an oil to coolant heat exchanger.

Btw, I'm still sticking to this: at 40C a 55 cSt oil will flow faster through an engine (and pick up more heat) than a 65cSt oil.

How do you figure? What if the slower (supposedly) flowing thick oil has more time to pick up heat?

 

[Gary Allan]

Originally Posted By: SpitfireS
How long does it take for the coolant thermostat to open after a "cold" start?
I'll bet: way less than 20 minutes of driving.
IOW: heat is being removed from the engine instead of it being fed to the engine oil (to reduce cold oil wear)

Solution: get an oil to coolant heat exchanger.

Btw, I'm still sticking to this: at 40C a 55 cSt oil will flow faster through an engine (and pick up more heat) than a 65cSt oil.

I say a a 55Cst oil will travel just as fast as a 45Cst oil unless that viscosity results in pressure exceeding the limits of your oil pump.

I somewhat agree on the heat exchanger. It will delay your time to temp slightly. It can work better in total cooling than both escape routes in isolation.

We still don't know if cold wear is from cold oil or cold engine. By shunting excess coolant heat to the oil, you're also limiting the oil's absorption potential for btu's ..that is, you're providing premature thermal back pressure ..taking waste heat that would normally go out the exhaust or radiator and applying it to the normally cold oil that would be a heat sink.

So, is the reduced wear due to warm oil ..or a faster thermally saturated engine due to the retained heat that warmer oil provides? Does hot oil apply AW packages quicker ..or does the fully warmed surfaces that they bond on have more impact?

All of my vehicles have laminar heat exchangers. A DONUT to you Euro's

 

[Taylor]

Gary you're so good with words! While the topic is viscosity, are you still running any featherweights?

 

[Gary Allan]

Yes. After an Auto-Rx round in an attempt to purge a moly slug hanging around somewhere inside by 2.5 ..Bruceblend 0w-10 Molyfree Stealth Formula will be in for the (add exceptional annunciation) grueling summer heat.

 

[Taylor]

Awsome can't wait, once I get my stroker together I'm gong to do something similar with the 4.0. It's on it's last leg, might as well have fun. I plan on running a zinc free for a long oci, then switch to a featherweight. Hardly scientific or conclusive in any form, but interesing none the less. Cheers

 

[il_signore97]

Okay, I'm a bit late to the party here, and I will admit, that I'm guilty of not 'completely' reading this thread properly, but, I think there is one thing that was not considered here.

I think its mostly accepted that most wear comes from start-up / warm-up cycle on a cold engine. Probably true, although I cannot personally attest to this. I think people generally assume that this increased wear during cold start/warm-up cycle is simply mechanical. But this may not be true.

I read an article (sorry, forgot to copy the link and now I can't find it) that actually studied where this start-up wear was actually coming from. It was limited to cylinder walls, as this is supposedly the area of highest wear on start-up / warm-up cycles. It was stated that up to 80% of this start-up wear was actually chemical wear (read: corrosive wear) on the cylinder wall liners rather than mechanical wear. If this is actually true, which it might be, then oil viscosity really has very little effect on this start-up wear. In other words, the cold "thick" oil may actually protect just fine (assuming parts are not starving for oil). However, due to increased fuel trim, acid formation, low cylinder temperatures, etc, cylinder walls wear chemically for the warm-up period. The cold oil probably cannot control this wear properly until it warms up, and additives begin to work more effectively.

This coincides with people saying they see less cylinder wear with hotter thermostats, as well as the study seeing less wear with warm starts an warm oil.

I don't think anything like this was considered yet in this thread... Thoughts?

 

[BuickGN]

Originally Posted By: il_signore97
Okay, I'm a bit late to the party here, and I will admit, that I'm guilty of not 'completely' reading this thread properly, but, I think there is one thing that was not considered here.

I think its mostly accepted that most wear comes from start-up / warm-up cycle on a cold engine. Probably true, although I cannot personally attest to this. I think people generally assume that this increased wear during cold start/warm-up cycle is simply mechanical. But this may not be true.

I read an article (sorry, forgot to copy the link and now I can't find it) that actually studied where this start-up wear was actually coming from. It was limited to cylinder walls, as this is supposedly the area of highest wear on start-up / warm-up cycles. It was stated that up to 80% of this start-up wear was actually chemical wear (read: corrosive wear) on the cylinder wall liners rather than mechanical wear. If this is actually true, which it might be, then oil viscosity really has very little effect on this start-up wear. In other words, the cold "thick" oil may actually protect just fine (assuming parts are not starving for oil). However, due to increased fuel trim, acid formation, low cylinder temperatures, etc, cylinder walls wear chemically for the warm-up period. The cold oil probably cannot control this wear properly until it warms up, and additives begin to work more effectively.

This coincides with people saying they see less cylinder wear with hotter thermostats, as well as the study seeing less wear with warm starts an warm oil.

I don't think anything like this was considered yet in this thread... Thoughts?


I briefly mentioned the differences I've noticed going from a 160 to a 190 degree thermostat when I went to aluminum heads. At least I think it was in this thread. My car is setup to be in closed loop feedback at 120 degrees if I remember right yet I saw less cylinder wear with the 190 stat. Is it a clearance issue, cold start enrich, or cold vs warm oil, I don't know. My oil temps always ran about the same due to a nice large external cooler.

 

[Gary Allan]

Quote:
I don't think anything like this was considered yet in this thread... Thoughts?


You're right, it hasn't been explored here (I don't think). I'd probably put it the other way around. We're pretty sure that fuel enrichment can exacerbate wear issues. I don't know about the term "chemical" wear, but cylinder wash down would surely reduce any lubrication properties of any oil film ..hot or cold.

Just keep in mind that the wear curve is only flat after about 20 minutes. That would be long after any effects of fuel enrichment were long gone. This would suggest that we're still back at the thermal aspects of the engine and the oil.

..but if fuel was the principle antagonist here, one would merely need to avoid the fuel enrichment process to totally eliminate the speculative/alleged 80% of the article you're talking about. That would mean that just about anyone using a block warmer could have next to zero wear ..just like those who refer to hot oil being the king pin in the mix could achieve radical reductions with a pan heater.

So far, I've seen no SAE paper that has shown 80% reductions in normal "startup" wear by employing such devices (or simulate warmed up conditions) compared to control engines that did not.

 

[Big Jim]

And really, just how much wear are we talking about? When is the last time you needed a ridge reamer to get rid of the ridge before pulling pistons without breaking rings? It has become common to overhaul an engine without boring the cylinders to make them round again without any wear taper. Actually, it has become uncommon to need to do an overhaul at all, but when engines are torn down even with lots of miles there is no significant cylinder wear.

 

[JAG]

Gary, I think the chemical wear he's referring to is from acidic water condensing on the cylinder walls. When the engine reaches normal operating temperature, the water vapor formed during combustion is less able to remain the more harmful liquid state on the metal and also, due to that, the acidic species can't do as much harm. I'll search for the paper he's referring to and report back if I find something good.

Ok, not THE paper, but here is a good book and the one paragraph on the page that should open mentions what I said: http://books.google.com/books?id=CgsHANZ...result&resnum=2

 

[Gary Allan]

JAG - you're way too good to me, pal

Surely there are these "process variables" involved in total wear of the unavoidable nature. Acid formation would surely be one of the contributing antagonists. What we don't know is how much.

Isolating some things are easy. You can eliminate the majority of water vapor/acid fromation by testing with low or no humidity air. I imagine any of the aforementioned preheating methods would work too, at least to a significant degree ..which would still leave us with the same difficulty in factoring which is the chicken or the egg.

..I guess the easiest way to word the question ..would be to ask, "What is the principle element that allows the cessation of startup wear and allows the engine to transition to steady state wear". Heat is only the required facilitating ingredient for the wear process to go into retreat. We still don't necessarily have the mechanism nailed down.

 

[JAG]

Gary, water is a product of gasoline combustion so testing with low of zero humidity air can only do so much. I seem to recall that so much water is formed during combustion that more water is produced than gasoline is burned.

I wish I knew the principle element that allows the cessation of start-up/warm-up wear. I suspect there are at least a handful of elements and their relative contribution toward the increased wear varies depending on many other factors. That would be a messy thing to characterize well. It would take a heck of a lot of testing. This thread may go on indefinitely trying to get to the root of it.

 

[AEHaas]

The humidity of intake air is a significant, independent, factor for engine wear and is specified in most current engine tests plus or minus a few percent.

This is contrary to intuition as the products of combustion are CO2 and water.

aehaas

 

[Gary Allan]

I'm sure you've got some fracturing and reformation in the combustion process. Just like you'll have your choice of NOX or CO when you're above 2xxxF without EGR depending on the a:f ratio.

Can you get one gallon of water out of one gallon of fuel consumption? I would think that you would normally suck in many more gallons with the CFM consumed in the same process.

I really am glad you're such a nice guy

 

[Gary Allan]

Well, my friendly tutor has shown me that 1.42 gallons of water is produced in the combustion of a gallon of gas.

 

[BuickGN]

Originally Posted By: Gary Allan
Well, my friendly tutor has shown me that 1.42 gallons of water is produced in the combustion of a gallon of gas.


Seriously? I guess some of this is coming from the air, where else could it come from?

 

[Bryanccfshr]

You put alot more air than fuel through the combustion proccess.