Dry starts...myth or fact ?

[Shannow]

When I bought my BMW a few months ago, there were parts galore that came with it, including a perforated block.

The assembled short engine had been standing in a corner, on it's flywheel for nearly two years.

Disassembled it so as to maximise the scrap value of it, and also get an idea how the little BMW sixes are constructed (I was quite impressed...nothing earth shattering but sound design...bushed rod ends, dowled big ends, double counterweights per throw, very snug fitting main bearing caps etc.)

The bearings were literally full of oil. The ring grooves similarly.

No way would I describe that engine as being "dry", even 'though it had been stored vertically.

 

[Merkava_4]

It's the ongoing centuries old debate -

What's more important: the engine getting thin oil in a millisecond because the engine is dry, or the engine having a nice cushion of thicker oil staying on the bearings over night ready for the next start?

 

[KW]

I'll say "dry starts" are a marketing myth.

Even the cams on a junky Ford mod. motor aren't "dry" after sitting over night. They hammer for a few seconds after start up not because they are dry but rather six feet from the oil pump.

The whole dry start thing is marketing.

 

[Master ACiD]

oil doesnt really evaporate and once a metal is wetted with oil it doesnt just drop off and go away like water.

 

[KORKL]

The marketing of synthetic oil really takes advantage of the "dry start" myth don't they? Synthetic is described to cling to metal surfaces better creating a protective coating. Sounds like conventional oil is already doing the same thing right? Thus, no need to worry about using a synthetic for faster flow.. (???)

 

[Dr_No]

Oil film is always present on start up

 

[KORKL]

Quote:

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Oil film is always present on start up

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Thus, the need for synthetic oil is a farse?

 

[dwendt44]

"..the need for synthetic oil is a farse? "

No, just hyped. There are real advantages to synthetic oils;
it's just that not everyone needs it.
It all depends on your preferences, driving habits, engine needs/design, weather, and how reasonable your maintenence habits.

?

 

[98LSC32V]

Quote:

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I'll say "dry starts" are a marketing myth.

Even the cams on a junky Ford mod. motor aren't "dry" after sitting over night. They hammer for a few seconds after start up not because they are dry but rather six feet from the oil pump.

The whole dry start thing is marketing.

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the timing chain tensioner is what makes the noise for a few seconds, and there is no such thing as a junky ford modular motor.

 

[Titan]

It's a fact that it's a myth. Or, it's a myth that it's a fact.

 

[Lonnie]

If you wanted a dry start how would you get all the oil off every friction effected part without taking the engine apart? It's like the whistle that keeps elephants away in Central Park in New York. Those whistles really work. In 200 years no one has been attacked by an elephant that had one of these whistles.

 

[Black_Thunder]

Quote:

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I'll say "dry starts" are a marketing myth.

Even the cams on a junky Ford mod. motor aren't "dry" after sitting over night. They hammer for a few seconds after start up not because they are dry but rather six feet from the oil pump.

The whole dry start thing is marketing.

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I've owned 2 of these supposed "junky" cam engines, which frankly i think is the most durable engine i've had since the 300 inline, and i've never had a problem with dry starts from sitting overnight or week.

i might have had it a couple times right after i got my first t-bird, but i switched to all motorcraft filters and i haven't had a problem since.

 

[Gary Allan]

How much myth is actually stated as "dry starts"? The most promoted event is "start up wear". The wear that occurs for the first 20 minutes of operation. They just leave that detail out. I'm sure that it's higher in the front end of the event than the hind end. I believe that it looks like an amortization chart on a 20 minute mortgage ..though it may not be a straight line....

 

[aquariuscsm]

I know on my car,thin oils give it lifter chatter on cold mornings. But with thicker oil she purrs like a kitten on cold startup. There`s nothing scarier than a noisy engine on a cold morning start!

 

[Curious Kid]

Gary Allan - I think if they were to make light of the "20-minute" wear event, they would have a much harder time getting people to change lubricants. I mean, how might an oil account for poor part fit due to thermal inequality and relative expansion? How about active protection that's less thermal dependent as it has been thought most of the anti-wear additive package has been thought to be so dependent?

Some areas just need pressure, like hydraulic lifters or a chain tensioner, to function properly. the further from the pump and the thicker the lubricant, the slower is the systems response as some have hinted above. Should a line bleed-off or leak enable emptying of such a supply line, the more it will aggravate the situation (deviation from adequate), at each start-up event.

Circumstantial.

Take care.

 

[Merkava_4]

Quote:

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Oil film is always present on start up

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But is there ENOUGH oil film? That's where the correct choice of viscosity comes into play.

 

[TallPaul]

The Ford modular engines may not be junky, but they scare me off. I am not interested in an engine that has several feet of cam chain hanging off the front of it. I know a guy who'se Crown Vic modular had the chain go out and the engine was history. Interference engine. When I upgraded to a newer motorhome (a 2000) I went Chevy for the pushrod 454 instead of a modular in a Ford, and I was a die hard Ford guy, but this Chevy has been treating me well.

As for oil film, a crude test (probably on the same level as freezer tests of oil flow) would be to dip a bolt in the oil and stand it up on a shelf to see how much oil remains on it after a day, week, month. Once worked for a guy who claimed he had done that with Rislone and it remained coated, the point being that Rislone will be good for your engine on start up, but he never ran the control with regular motor oil.

 

[Merkava_4]

^ I like crude tests TallPaul; I can understand them.

 

[mechtech2]

After two years of sitting on it's end, I am suprised that the bearings and rings were "full" of oil.
I wish I have a gun oil that good!

 

[Shannow]

Quote:

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After two years of sitting on it's end, I am suprised that the bearings and rings were "full" of oil.

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That's what shocked me.

Didn't take rags or anything substantial, expecting nothing like what I found.