Thin oil.
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Mountain Pass
Joined: Apr 2008
Posts: 174
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Thin oil.
It dosn't seem right that Ford recomends such thin oil. I talked to a Mobil engineer a year ago and he recomended 15w50 year round for any flat tappet cam engine. Im sure this V10 is a roller motor so it uses thinner oil but why so thin. I have 55 k miles and it runs good but think I would like to run the same 15w50 synthetic I put in everthing else.
What are you running and why?
What are you running and why?
Postmaster
Joined: Jun 2008
Posts: 2,564
Likes: 11
From: Wayyy NoCal, USA
Why so thin? Much better oils and better machining processes allow much tighter bearing clearances. This provides longer engine life, faster oiling at start up, and less friction. It really is a good thing.
If the oil is too thick, it will be difficult to force it into those tiny clearances, meaning no oil film in the bearing, especially at start up. No oil film means those bearing clearances will get a lot bigger, really fast.
As an engineer, I have to advise following recommendations unless you have a special situation or special knowledge.
If the oil is too thick, it will be difficult to force it into those tiny clearances, meaning no oil film in the bearing, especially at start up. No oil film means those bearing clearances will get a lot bigger, really fast.
As an engineer, I have to advise following recommendations unless you have a special situation or special knowledge.
Hotshot
Joined: Mar 2007
Posts: 10,101
Likes: 40
From: Pa
Do a search and find a pic of a torn down modular head casting. The cam journals ride on machined aluminum bosses with NO bearings. A thinner oil is best to get up there and lubricate the journals. Many other possitives for thinner oil. I run 10w-30 in my 35+ YO 302 with no problems. I don't run gear oil in my engines.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
15w50 is WAY too thick.
Over the years here at FTE, we've had a few people drop in both here in the V10 forum, and the 4.6/5.4 forum complaining about top-end noises.
Guess what they did? Ran a thick oil for years and then wondered why the cam journals were hogged out, or the cam lobes were scored, or some other top-end issue.
Cold-start is the worst time for engines, especially overhead-cam engines. The thin oil gets up there quicker.
Over the years here at FTE, we've had a few people drop in both here in the V10 forum, and the 4.6/5.4 forum complaining about top-end noises.
Guess what they did? Ran a thick oil for years and then wondered why the cam journals were hogged out, or the cam lobes were scored, or some other top-end issue.
Cold-start is the worst time for engines, especially overhead-cam engines. The thin oil gets up there quicker.
Elder User
Joined: Jan 2007
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Do a search and find a pic of a torn down modular head casting. The cam journals ride on machined aluminum bosses with NO bearings. A thinner oil is best to get up there and lubricate the journals. Many other possitives for thinner oil. I run 10w-30 in my 35+ YO 302 with no problems. I don't run gear oil in my engines.
Elder User
Joined: Jan 2007
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Do you know the difference between 10winter-30 and 5winter-20
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Mountain Pass
Joined: Apr 2008
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10w30 flows like a straight weight 10 when it's real cold and thickening agents in it make it flow like a 30 weight when it's real hot. They basically dump it in a funnel and count the seconds it takes to flow out. 10 seconds=10 weight 30 seconds is 30 weight. The w in 10W30 stands for winter but it's basically 10 weight oil with crap in it to slow the flow when it's hot. Ever wonder why racers use straight weight? Because all those additives are not oil and not much of a lubricant either. They break down in time and turn to vapor. Thats why your oil stays full for a long time then all of a sudden your mysteriously 1/2 quart low. The additives turned to vapor and went thou your PCV. That tells you it's time to change it no matter what the miles are.
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Posting Guru
Joined: Mar 2005
Posts: 2,060
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From: Burnsville, MN
That's the explanation I always understood relative to oil weight designations, but I got a real eye opener this winter. I left a quart of 5W20 dino oil and one of Mobil 1 synthetic oil out in -20 temperatures overnight, then poured them the next morning. Hugh, hugh difference! Somehow or other the ratings definitions of oil must have changed over the years....
Sit. Stay.
Joined: Oct 2001
Posts: 18,308
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From: Washington State
Multi-viscosity oil DOES NOT THICKEN when hot. It resists thinning. Your X weight (insert first number here ) will never thicken to become XX (insert second number here ).
A 5W-20 weight oil is a 5W base stock that will resist thinning as much as a 20 weight would at 100°C. Think of it as a percentage. Not that it thins 20% but more if a 20 weight oil thins "X amount" at 100°C then the 5-weight base stock will only thin as much as well.
Only gravy thickens when hot.
Barebones, the difference you noticed between the two oils is due to the molecular makeup. The dino's molecules are not uniform hence the thickening. Synthetic oil have molecules that are all uniform and do not "bunch up" like that.
A 5W-20 weight oil is a 5W base stock that will resist thinning as much as a 20 weight would at 100°C. Think of it as a percentage. Not that it thins 20% but more if a 20 weight oil thins "X amount" at 100°C then the 5-weight base stock will only thin as much as well.
Only gravy thickens when hot.
Barebones, the difference you noticed between the two oils is due to the molecular makeup. The dino's molecules are not uniform hence the thickening. Synthetic oil have molecules that are all uniform and do not "bunch up" like that.
Posting Guru
Joined: Mar 2005
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From: Burnsville, MN
Thanks, Monsta. Whatever the explanation its clear that synthetic is the better oil in Northern winters.....
The real question is though, if one oil flows so much faster than another, how can they both meet the same standard?!
The real question is though, if one oil flows so much faster than another, how can they both meet the same standard?!
Postmaster
Joined: Nov 2008
Posts: 3,938
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From: BC Canada
I always use 5w30 Mobil 1 synthetic oil in my modular motor fords.
I have never had anything but great results from Mobil ! oil.
It also gives me a little extra protection on a scorching hot summer day, pulling a 9,500 pound trailer up a mountain pass.
I have never had anything but great results from Mobil ! oil.
It also gives me a little extra protection on a scorching hot summer day, pulling a 9,500 pound trailer up a mountain pass.