Reply
 
Thread Tools Display Modes
 
Old 12-18-2014, 08:06 AM   #41
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,525
Pour out some 0-xx synthetic at 30 degrees and then see for yourself the difference. If you want to reduce wear the solution is obvious

You will see the difference , but your geared oil pump wont.

Most bearings require oil pressure as they ride on the pump action caused by the space between say rods and crank.

The tappets rely in film strength , as does the piston after the rings have scraped 99+% of the oil away.

>but they are only shut down for oil changes (unless they can be hot-oiled?)<

Long life Prime gen sets may have 2 oil tanks , each pre heated by a line from the engine that are simply switched as the oil change is done.
__________________
Advertisement

FF is offline   Reply With Quote
Old 12-18-2014, 11:47 AM   #42
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Scott wrote;
"Is every bearing surface on an engine forced lubed across its entire surface?
I have always been taught, no."

I have not been taught anything in that regard but common sense would indicate that;

First the question isn't about "forced lube" but "is there oil on the bearing surfaces that will keep the metal bearing surfaces from touching each other"? Notice I didn't say "enough oil" or anything about pressure. It's about keeping the metal surfaces apart. And if they were not kept apart serious damage would result.

Secondly looking at an oil pressure gauge while starting an engine indicates there is no oil pressure at the oil pressure sending unit or sensor for several revolutions. Nobody can be sure of how much damage (if any) is done during these few revolutions but millions of engines all over the world have this experience daily. And if it were an actual problem engines would be equipped w pre-lubers.

What was the oil system on the Chevy's in the 30's and forties? As I recall it was refereed to as a "splash" system. And I think this system relied on the crankshaft splashing oil around in the crankcase. I think they had an oil pump and pressure fed bearings on the crankshaft and elsewhere but relied on splash oil for cylinder wall lubrication. But not sure. Does anybody remember how those old Chevy's got lubed?
__________________

__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 12-18-2014, 12:04 PM   #43
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Country: Canada
Vessel Name: Gwaii Haanas
Vessel Model: Vancouver Shipyards Custom Aluminum 52
Join Date: Sep 2013
Posts: 2,447
FF of course, dry-sumped. Easy-peasy.

I stand by my position - just read the label, choose the correct standard and just put oil in it.

Cooler failure
Manufacturing defect
Ingesting salt water
Coolant failure/overheating
Owner doing something stupid/operator error
Maintenance neglect (change that oil occasionally)
Correct oil level

Type of oil? No

Best way to get long life out of your engine? Use it lots.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 12-18-2014, 12:13 PM   #44
Guru
 
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 6,369
I have seen the test data where bearing surface film strength and retained oil is measured over time. This data reveals how long an oil film will hold up with an engine shut down thus allowing startup safety before oil pressure build up. Under identical shutdown test conditions some oils are retained on bearings for weeks and others days.

Don't ask me for details as this was some time ago, but is indeed how Cat and others come to specify acceptable oil brands and offer and stand behind new engine warranties. I'd presume this is why one does not buy an el cheapo oil and goes for the "better" stuff. I saw a gallon of DELO 400 yesterday at WalMart for $13. Pretty cheap insurance.
sunchaser is offline   Reply With Quote
Old 12-18-2014, 01:37 PM   #45
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Very interesting Tom.
I kinda like it when my cars don't start immediately .. acts like a preluber. I have an old Nissan Stanza that starts instantly and wonder if that's desirable. Not much wear on the starter motor though. That would be nice for an Alaska bound boat and most of us have a way of doing it. I can crank my engine over at idle for 5 to 10 seconds w/o the glow plugs on. Then turn on the glow plugs for 8 to 10 seconds and start instantly w a pre-lubed engine.

Wonder what in the oil would cause it to cling to metal for longer periods. Like VI improvers it would be something in the oil that would not be oil and thus may reduce the lubricity of the oil some small amount. But perhaps it's not like an additive and the "characteristic" is found in the "base stock"?

It's been shown that buying a brand name product from other than a trustworthy and time honerd source can result in buying an inferior product. Sorta like "seconds". I have for most all my life thought a top brand product was just that whoever you bought it from but no more. Case in point .... "Outlet stores". They sell merchandise that will not be shipped to "mother stores". I don't go into WallMart stores for other reasons but I think it depends on many variables so often or much of the time the product is exactly the same whatever store it's sold in. Don't really know but I do think a product is more likely to be as the brand suggests at it's prime outlet source. Like Shell oil at a Shell gas station. We live in a much more complicated age now as consumers.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 12-18-2014, 02:44 PM   #46
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
[QUOTE=manyboats;291683]Oil is not compressible (as far as I know) and oil pumps in engines are positive displacement gear pumps so at any given engine speed the amount of oil pumped through an engine is the same w any viscosity oil used.

Tell me if I'm wrong about the above and I'll change my tune.

Respectfully, you are wrong. The same amount of oil goes through the pump but in all the engine bearing gaps less oil goes through when the oil is cold and more goes through when the oil is hot. When less oil is flowing more is diverted through the engines oil pressure relief system. When more is flowing less is by-passed. Viscosity is important to change the way oil flows at different temperatures, You should use the oil viscosity the engine manufacturer calls for because he has done the testing and has a basis for whatever he calls for.
obthomas is offline   Reply With Quote
Old 12-18-2014, 02:50 PM   #47
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
Quote:
Originally Posted by manyboats View Post
What was the oil system on the Chevy's in the 30's and forties? As I recall it was refereed to as a "splash" system. And I think this system relied on the crankshaft splashing oil around in the crankcase. I think they had an oil pump and pressure fed bearings on the crankshaft and elsewhere but relied on splash oil for cylinder wall lubrication. But not sure. Does anybody remember how those old Chevy's got lubed?
Chevy 216 and 235 cu in engines had circular channels under each rod in the oil pan. Each rod had a scoop. As the crank turned the scoop on the bottom of the rod traveled along the channel and scooped up the oil. This created a pressure and oil was then pressed up through the engine oil galleries. Every time the rod came around into the oil it scooped a little more oil.
obthomas is offline   Reply With Quote
Old 12-18-2014, 03:12 PM   #48
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
obthomas,
So there is/was no convential oil pump. I kinda thought so but decided surely there must be. So most of the engine probably starts w/o oil pressure or oil flow to it's bearings. In their day they were considered a long lasting engine so it adds to the idea that residual oil in engine bearings provides adequate luberication.

Re post # 46 how can less oil flow through the bearing when the engine is cold when the source of oil remains the same .. the pump. I would suggest that the same amount of oil flows through the bearings but at a different velocity. Just like when a river widens the current slows but the volume remains the same. But the amount of oil in a worn bearing would be greater offering several advantages including more "cushion". More oil in there to "squish" out.

So the volume of oil passing through the engine is the same irregardless of the viscosity rating.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 12-18-2014, 03:27 PM   #49
Guru
 
River Cruiser's Avatar
 
City: UMR MM283
Country: US
Vessel Name: Northern Lights II
Vessel Model: Bayliner 3870
Join Date: Jan 2013
Posts: 1,228
It's a good thing the excavating contractors I worked for didn't worry as much about oil and their engines as boaters, if they did we wouldn't of moved much dirt😉.
__________________
Ron on Northern Lights II
I don't like making plans for the day because the word "premeditated" gets thrown around in the courtroom.
River Cruiser is offline   Reply With Quote
Old 12-18-2014, 03:29 PM   #50
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,887
Quote:
Originally Posted by manyboats View Post
obthomas,
So there is/was no convential oil pump. I kinda thought so but decided surely there must be. So most of the engine probably starts w/o oil pressure or oil flow to it's bearings. In their day they were considered a long lasting engine so it adds to the idea that residual oil in engine bearings provides adequate luberication.

Re post # 46 how can less oil flow through the bearing when the engine is cold when the source of oil remains the same .. the pump. I would suggest that the same amount of oil flows through the bearings but at a different velocity. Just like when a river widens the current slows but the volume remains the same. But the amount of oil in a worn bearing would be greater offering several advantages including more "cushion". More oil in there to "squish" out.

So the volume of oil passing through the engine is the same irregardless of the viscosity rating.
Not so. Engine oil pumps have pressure regulating valve that open if pressure goes above a certain level. Cold engine the valve is usually open and a good bit of oil is diverted back to sump. Flow at the bearings is then very slow due to the viscosity. But the bearings are happy, you don't need pressure, just need the presence of oil. Pressure assures presence!!

On a cold start, the bearings usually still have a hint of oil present, enought that metal to metal contact ends after say a quarter turn of crank. Engine might make some noise til pressure comes up and floods bearing, but that does not mean bearing is being damaged.

That's why most engine guys don't bother with prelube pumps.
Ski in NC is offline   Reply With Quote
Old 12-18-2014, 03:38 PM   #51
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
Also thin oil film bearings on rods and cranks are coated with babbit. A tin like materal. This babbit protects the metals when they do touch for that instant on start up. The babbit doesn't go any where it just smooths out for the next time the engine is started.;
obthomas is offline   Reply With Quote
Old 12-18-2014, 04:03 PM   #52
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Country: Canada
Vessel Name: Gwaii Haanas
Vessel Model: Vancouver Shipyards Custom Aluminum 52
Join Date: Sep 2013
Posts: 2,447
Yes, you do need pressure. If there is no pressure, the oil is quickly removed from the bearing surface, the metals of the "bearing" touch and you sustain damage. You can mitigate this effect if you have very smooth surfaces and you have an oil film present. This oil film will dissipate very rapidly, but on startup, the oil pump provides pressure to the bearings (perhaps not yet the gauge) and you have minimal damage. Also, there are much lighter loads except rotational loads on the main bearings until the engine fires, which is when the oil is essential. The noise you hear on startup is the valve train, which is not loaded the way that the "big ends" are, do not need the oil film immediately and will quieten as soon as the oil circulates.

Having said all that, the engines are spec'd to last so many hours before rebuild. If you never shut them off, or if when you did, you pre-lubed them like a large ship's engine would be, they will go longer. Cummins says a particular engine will last "100,000 gallons of fuel," I don't remember the actual amount for my engine, but that is contingent upon its duty cycle, in my case M1 or continuous.

They know that if their engines are used as per the duty cycle, started "dry" and from cold, they will go that long. Then they are worn out and need a rebuild.

If the oil pressure fails and the oil film in the bearing dissipates, you will have instant damage from which the bearing will never recover. The engine may run for some time after this occurs but you have significantly shortened the life of the engine. It is oil pressure that prevents this, not the type of oil.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 12-18-2014, 05:02 PM   #53
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
oK good,
Forgot about the pressure relief valve and some other stuff. Good learning thread. Something else I remember from the past is that pounding main bearings and hammering rod bearings would last some time if rpm was not excessive. I wonder if metal to metal contact was being made w the knocking. I doubt it but what would make the knock?

At any rate I believe bearings will be happy as long as the oil is there in sufficient quantity and of high enough viscosity to keep metal from metal.

I just bought a 2nd Suburban that has a "crate" engine and think it is spect'd for 5W-30 oil. That's what the PO said and I don't know if the automatic transmission is original. I could use a reduction in friction there.

River Cruiser,
I for one am not worried about any of this stuff. And will continue using straight 30 wt dino oil in my Mitsubishi until somebody shows me a need for something else.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 12-18-2014, 08:42 PM   #54
Guru
 
BobH's Avatar
 
City: Montgomery, TX
Country: USA
Vessel Model: None, but looking
Join Date: Feb 2012
Posts: 778
Positive displacement gear pumps are only really "positive displacement" when new. As soon as thing start to wear, oil will be bypassed internally between the gears in the pump. The only truly "positive displacement" pumps are diaphragm pumps where there is no chance of leakage from the pressure side to the suction side.


Bob
BobH is offline   Reply With Quote
Old 12-19-2014, 10:25 AM   #55
Senior Member
 
mike66's Avatar
 
City: Warwick, RI
Country: USA
Vessel Name: Susan Helena
Vessel Model: Albin40
Join Date: Oct 2014
Posts: 181
Quote:
Originally Posted by BobH View Post
Positive displacement gear pumps are only really "positive displacement" when new. As soon as thing start to wear, oil will be bypassed internally between the gears in the pump. The only truly "positive displacement" pumps are diaphragm pumps where there is no chance of leakage from the pressure side to the suction side.


Bob
The intake side is beginning neglected too. Flow into the pump will have an impact on outflow. Think of trying to pump grease vs oil out of a bucket with the same pump and intake screen as in our engines. Worst case the grease doesn't flow at all.
mike66 is offline   Reply With Quote
Old 12-22-2014, 01:49 PM   #56
Guru
 
kchace's Avatar
 
City: Brookline, NH
Country: USA
Vessel Name: Blue Heaven
Vessel Model: Albin 43 classic double cabin, twin 135 Lehmans
Join Date: Sep 2013
Posts: 759
Quote:
Originally Posted by mike66 View Post
The intake side is beginning neglected too. Flow into the pump will have an impact on outflow. Think of trying to pump grease vs oil out of a bucket with the same pump and intake screen as in our engines. Worst case the grease doesn't flow at all.
This and the previous post were proven by me back when I was young and (more) naive. I thought if 20w-50 was good in the summer (In NH) it should be fine in the winter. On really cold days (10-15 deg) it could take 30 seconds of running for the oil pressure to rise from zero! After a couple of winters of this, the bearings were shot. So no, the oil pumps are not really positive displacement and flow at cold means a lot. Sure we don't have this extreme in our boats, but its an extreme example of what happens at startup with cold flow.

Ken
kchace is offline   Reply With Quote
Old 12-22-2014, 02:11 PM   #57
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
You should use the oil weight that the engine manufacturer recommends for the temperature where you operate.
obthomas is offline   Reply With Quote
Old 12-22-2014, 02:38 PM   #58
Senior Member
 
mike66's Avatar
 
City: Warwick, RI
Country: USA
Vessel Name: Susan Helena
Vessel Model: Albin40
Join Date: Oct 2014
Posts: 181
Quote:
Originally Posted by obthomas View Post
You should use the oil weight that the engine manufacturer recommends for the temperature where you operate.
Absolutely. Unless the specs were written 30 years ago and something newer has come along that may surpass those specs. Oil is probably at the bottom of the list of reasons for engine death, except for lack or loss of it. Under extremes of temperatures and service it becomes more important.
mike66 is offline   Reply With Quote
Old 12-22-2014, 02:56 PM   #59
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
kchace,
You don't mention what kind of vehicle this engine was in. And those temps aren't really that cold for road vehicles. Never heard of anything like that happening before. In college I drove a 1950 Plymouth to work 10 miles away often slightly below zero degrees F. Was hard to start as it cranked so slow but it always eventually started and got me to work. My 12 volt Mercury would not. But in our boats most of us keep our engine compartments well above freezing as the seawater has no anti-freeze in it and is vulnerable to freezing. Do you think there could be another reason for your bearing failure?

obthomas,
Yes but changing the viscosity on an older engine could have a downside as the engine was designed for what was originally specified. 1960 30W Chevron diesel lube oil is much improved in the new modern 30 W product. Most likely the only feature not incorporated in today's 30 W oil is the MV capability. And that's not exactly a new feature of oil. IMO we don't need MV oil in our boats.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 12-22-2014, 03:11 PM   #60
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
My engines are 30 years old and the stickers on the engines call for API CD 20W30 oil.

Now the CD specification is long gone but the 20W30 is still the same as it was 30 years ago. When you look up the CD specification and see that it is obsolete you have to surmise its replacement and when you do you will find that the CD is most equivalent to a current API service rating of CI-4. The 20W30 viscosity rating is still available in this oil today. Since I change oil at 100 hours or each season I have found no reason to go to synthetic or synthetic blend. I remain convinced these thirty year old engines will last longer than me. I use and will continue to use CI-4 20W30 oil.
__________________

obthomas is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 01:22 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012