oil consumption

MIKES342

I have 27 hours on my 260 with 6.2 Liter engine.  I used 1 quart of oil.  I am going to change the oil on Tuesday.  Is this normal during the breakin period. 

 

Mike

212rowboat

You're going to burn some oil on a new engine... It takes some time for the piston rings-to-cylinder walls magic to happen.. because of this you'll have a lot of blow by, which is gasses escaping the cylinder by slipping past that ring-to-wall marriage, instead of waiting for an exhaust valve to open.. it will cause pressures in your block, specifically the crankcase... The mechanisms in place to keep the gasses from causing serious issues is the positive crankcase ventilation valve, or pcv.. it feeds the gasses, which are laden with droplets of oil, through your throttle body via the air hat..

In the old days, and in automotive applications, this vented to the ground and left a nice sheen on roads.. landlubbers didn't like that too much, so some used a catch can.. those catch cans caught the oil and provided proof to how much can slip past the rings in new, as well as old and worn engines.. a quart wasn't terribly uncommon, especially on larger displaced engines.. some smart folks decided it was better to burn the oil than smear it on roads, so they devised the pcv valve being inducted into the intake, and poof!!! No more oily roads, but instead stanky exhaust... Well, stankier, anyway..

Watch it, my man, and see if it doesn't abate.. it most likely will..

You've floated about the equiv of driving a car 1200 miles or so... If it is running good, just hang with it a while longer.. its really too soon to really know anything, even with an oil analysis.. though an analysis will tell you if its breaking in normally or if there is really high counts of stuff that you don't want... Just make sure and tell them its a new engine.

Michael T

Mike the 6.2 is a great engine in that it is really strong. I believe that Mercury still "hand builds" them and the 8.2 Mag High Output. Regarding that quart of oil you mentioned some has gotten past the oil control rings as they seat and some is still in your oil filter. In my opinion your oil consumption is normal. I am sure the rate of usage will now taper off sharply. MT

212rowboat

just for the record, rings 'seating' isnt what it sounds like... 

the things are split.. its the only way you can get them on the piston.. they freely spin around, and sometimes line up gaps in the rings.. that is what happens with new engines... after a bit, the rings stop spinning and locate themselves in what becomes their permenant spot.. you can hope the gaps arent aligned, but thats all you can do.. they 'seat' when they stop spinning... ever wonder why some engines burn more oil or are plauged with more issues? its something you cant control... it happens either way it wants to happen.. before they seat, youll have excess blow by. 

TonyWalker

Drew, that is an interesting explanation.   It sound like you have to get lucky 8 times per engine.  I am breaking in two newbies.  Total of 8 hours so far.  Starboard engine has burned zero oil so far.  I put 250 milliliters in the port engine at my most recent run to top it up.  I guess this is pretty normal.  Yes?

Tony

Salt Shaker 342. 

Michael T

Tony, my 2 cents is that you don't have to get lucky to have a non-oil burner.. While it is true that oil consumption can vary per engine that variance should fall within normal parameters. After a proper break-in 1 quart in 20 hours would not be my definition of normal. The performance of assembly line marine engines can vary by +/- 5% but that refers more to horse power than oil control. I have owned 10 350 magnums ranging from the earlier carbed ones to the two 2013 350 Mags on the EC 310 that I just traded in. I stroked two of them changing them into 383s. NONE of them burned a quart in 20 hours, even the 383s that would propel the boat to 75mph on the gps. The last time I was around for a tear down of a MARINE non race engine we had 3 sets of control rings. A top set mainly for compression control and heat dissipation. A second set of compression rings for oil scraping (to stop oil from reaching the compressionchamber) with a seal to trap compression gasses. Then there were the oil control rings whose job it is to control oil loss. They often had two non concentric rails. There are a number of types: 3 pc flex vents(2 railed) 2 pc coil spring assisted, two piece inner springs and one piece. Anyway, if oil burning is a crap shoot (which I do not agree with) I have been lucky 20 or more times and had better head to Vegas right away. Oil control depends on the proper assembly on an engine with non-flawed parts by the manufacturer (yes some lemons escape). If you receive a properly constructed engine you need to break it in well. The first 10 hours is absolutely critical with warm-up to operating temperature, little idle, right onto plane and vary the rpms avoiding wot and avoiding lugging the engine at all costs (that is the real devil of engine damage and oil consumption). The next 10 hours, more of the same with the odd foray into wot. After that do not lug your engine - ever - try to stay off wot for longer than 5 minutes (unless a balanced race engine) watch your oil level and change your oil and filter as required. I totally believe in fully synthetic. I do not like the "new" smaller oil filters  whether automotive or marine and change my oil filters on my 350 mags between oil changes then top up my oil. Always change your engine oil after it has been heated to operating temperatures or at least 155 degrees to wash the engine of acids, condensed water vapour and contaminents off internal parts and into the oil for removal. If this is all done you should not "burn" oil. the only oil "burner" I ever had was a set of the old 502s that drank oil religiuosly. For excessive oil burning I look to improper operation (lugging or sustained wot) or an engine problem that is not normal.My 2 cents. Regards MT   P.S. The two 2013 350 Mags I just traded in have 65 hours on them. In the 0 to 22 hour period they may have consumed 2/3 of a quart BETWEEN them. From their oil change to merc fully synthetic at 22 hours to today's hours at 65 the oil has not moved on the sticks. I had better knock on wood as I hope I haven't just tempted fate. I sure don't want the new 502s in my 2014 EC 360 to turn on me and burn oil :-)  MT

212rowboat

rings seat most often with the gaps offset.. that is what you want.. its actually rare that they align, and there are mechanisms present that attempt to control the seat..  rings aligning, or not being on offset hemispheres is the biggest thing about breaking in a rotating assembly that a builder cant control... blah blah blah, though.. im sue all this will be corrected soon enough by somebody who "watches" builds happen..  

i cant say that i care if someone disagrees with me about this.. this is the way it is, and no wall of text can change that, no matter how many engines owned or how many times someone hangs around while the engine is being but.. 

Michael T

Drew, if your hypothesis was correct which I respectfully disagree and believe it isn't. Ring seating isn't a crap shoot it is a designed science and you "don't have to hope" that they align correctly. Excessive oil burning always has a culprit unless, as in the case of the old 502s it happened to all of them and was seen as a "normal" have to live with it flaw. MT  

212rowboat

Factors are mitigated, not eliminated.. Cylinder walls are cross hatched with an abrasive to creates tiny peaks and valleys, in effort to hone the cylinder wall to ring marriage/seal.. this is for the compression ring. Those cross hatches all by themselves allow blow by, as well as allow oil to be burned on each and every stroke, until the seal becomes permanent, and as the rings float around making their adjustments.. they will find a pattern they like, and lock down.. There are some steps that can be taken to attempt to fix a ring in an indexed position, but there isn't anyway to know for certain if it works.. whether you like it or not, sometimes a cylinder piston ring relationship will have aligned ring gaps, and will allow more oil by because of it.. Indicators are excess oil consumption, oil fouled plugs or excess carbon deposits on plugs, and in severe cases, a leakdown significantly faster, while wet, than the other cylinders.. You have to pull the piston out to see the truth, which really bites, because that is as deep in an engine as is possible, but that is the only way to see the whole truth.. Back on point: wait and see. Youll most likely find it goes away.. oil consumption, that is..

Michael T

Pretty much what I said a few posts ago. MT

212rowboat

27hrs @ 45mph is 1200ish miles... which is pretty consistent speed and hard to do off a track, unless you have a monstrous gas tank and a straight shot of highway...

my 6.4diesel has 62k miles, and 1800hours of operation, as a driving to hours comparison, and not to attempt to compare engine wear...

the steady RPM's most use their boats at is not near the same as the constant fluctuations used while driving, but the engines are better built to sustain it..

212rowboat

Michael T said:

Tony, my 2 cents is that you don't have to get lucky to have a non-oil burner.. While it is true that oil consumption can vary per engine that variance should fall within normal parameters. (1)-After a proper break-in 1 quart in 20 hours would not be my definition of normal. The performance of assembly line marine engines can vary by +/- 5% but that refers more to horse power than oil control. I have owned 10 350 magnums ranging from the earlier carbed ones to the two 2013 350 Mags on the EC 310 that I just traded in. I stroked two of them changing them into 383s. NONE of them burned a quart in 20 hours, even the 383s that would propel the boat to 75mph on the gps. The last time I was around for a tear down of a MARINE non race engine we had 3 sets of control rings. A top set mainly for compression control and heat dissipation. A second set of compression rings for oil scraping (to stop oil from reaching the compressionchamber) with a seal to trap compression gasses. Then there were the oil control rings whose job it is to control oil loss. They often had two non concentric rails. There are a number of types: 3 pc flex vents(2 railed) 2 pc coil spring assisted, two piece inner springs and one piece. (2)Anyway, if oil burning is a crap shoot (which I do not agree with) I have been lucky 20 or more times and had better head to Vegas right away. Oil control depends on the proper assembly on an engine with non-flawed parts by the manufacturer (yes some lemons escape). If you receive a properly constructed engine you need to break it in well. The first 10 hours is absolutely critical with warm-up to operating temperature, little idle, right onto plane and vary the rpms avoiding wot and avoiding lugging the engine at all costs (that is the real devil of engine damage and oil consumption). The next 10 hours, more of the same with the odd foray into wot. After that do not lug your engine - ever - (3)try to stay off wot for longer than 5 minutes (unless a balanced race engine) watch your oil level and change your oil and filter as required. I totally believe in fully synthetic. I do not like the "new" smaller oil filters  whether automotive or marine and change my oil filters on my 350 mags between oil changes then top up my oil. Always change your engine oil after it has been heated to operating temperatures or at least 155 degrees to wash the engine of acids, condensed water vapour and contaminents off internal parts and into the oil for removal. If this is all done you should not "burn" oil. the only oil "burner" I ever had was a set of the old 502s that drank oil religiuosly. For excessive oil burning I look to improper operation (lugging or sustained wot) or an engine problem that is not normal.My 2 cents. Regards MT   P.S. The two 2013 350 Mags I just traded in have 65 hours on them. In the 0 to 22 hour period they may have consumed 2/3 of a quart BETWEEN them. From their oil change to merc fully synthetic at 22 hours to today's hours at 65 the oil has not moved on the sticks. I had better knock on wood as I hope I haven't just tempted fate. I sure don't want the new 502s in my 2014 EC 360 to turn on me and burn oil :-)  MT

1- it's the definition others adhere to, so you're on your own on this one. proper break in doesn't happen in under 20 hours, so your comment is based on folly to begin with- but I'm sure you'll go edit it out like you did the last one (on an aside, it's your original content that set me off here, and though others reading may think I'm being a jerk, you and I know that I'm bridling my response, in attempt to keep it on point)... the man stated he has 27hours on the engine, which is enough time to marry rings to cylinder walls by a long shot, but not to determine if the entire rotating assembly is spinning as freely as it will when it loosens, exchanges oil between the surfaces that load (unloaded oil burns, too), and if the rings have taken their permanent positions yet..

2- oil burning is NOT a crap shoot, it is an inevitable trait of a new engine.. I'll go barney for you, because you may not have been paying attention while you were around watching your engines being built: cylinders are cross-hatched to create a microscopically abrasive surface for the piston rings to seal to the cylinder walls.. the valleys fill with oil on each and every stroke, and what is left over in those valleys gets burned during the power stroke.. it doesn't take long at all for the rings to marry to the walls of the cylinders- the cross hatching is done in a way that attempts to direct the rotation of the piston rings in a predictable direction, which is hopefully offset to one another.. most often, when the rings decide to 'seat', as in 'no longer spin around', they are off set, but sometimes they aren't..

3- 5 minutes? that is enough to kill an engine that isn't carefully balanced, and where you are demonstrating you really don't have a good grasp of what you're speaking... ever heard of a rev limiter? ever wonder why those are on there? ever heard of valve float? ever wonder why engines are limited below 6500rpm unless they have items such as beehive valve springs and carefully adjusted valves? (and this is speaking solely a portion of only valve train, there is a ton more on either side of that function).......... WOT (as defined by the rev limiter) is no problem on these things for five minutes- all it will hurt on a healthy engine and drive line is the economy.. take it to true WOT (no rev limiter), and it will self destruct in short order, especially if you decide to cross a wake, hit a chop, or do something else that alters the load on the engine..

Michael T