Mobile 1 here.

I have personally witnessed high-mile (over 120k) car engines begin leaking from crank seals after being switched over to synthetic from conventionals. The general consensus as to the mechanics of this issue is that the detergent package used in synthetics has one additional ingredient that is typically not compatible with the conventional bases. This ingredient is extremely effective in breaking down the sludge or parrafin that accumulates in engines over time (ever pulled a valve cover off an old station wagon?). High mile motors that have endured longer than average oil change intervals usually have a significant buildup in them. In addition to buildup around the rockers and in the lifter valley, there sometimes exists a substantial amount of hardened sludge IN the rubber seals in the motor (crank seals). As the sludge originally accumulated, it prevented the lubrication and cooling of the lip of the seal itself which burns the lip off the seal. The reason the seal never leaked is because the sludge itself became the sealing surface. Over a couple of weeks running the synthetic oil, the sludge is dissolved out of the old seals and - PRESTO - they leak.

Just passing info to others in case they do the above, get the leak, and can't figure out why.

Also, has anybody ever seen a sludged up motor that was running synthetics? I haven't but I wonder if syn lube is more resistant to sludge or not...

I concur.....Royal Purple

Mobile One Synth

?????
 

I find this surprising...........I've pulled apart a few engines that have run synthetic oil & have sat around for a few months or so. That chit is everywhere, on everything, & is still slick. It even seems like a chore to take the socket off of the ratchet when you get it on your hands from working with the parts !

Just kinda surprised

:rolleyes:

Drive Oil
 

The Merc mechanic who just rebuilt my Bravo 1's told me not to use synthetic because the clutch would slip.

Is that true?

NO

merc hi perf oil is synthetic...

PETE __

BEYOND ANY,,,ANY DOBT NO !!!!!!!!!!!!!!!!!

Don't even tell us would did your drive !!!!!!

If its a Bravo its clutchs don't work that way

:confused: :confused: :confused:

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They syn are almost sludge proof they hold dirt and matter insuspension longer than regular oil ,
Also if you add it to a high milage motor your right aleak could devlope a leak just keep driving and it will stop as soon as the syn.deposits build back up,,some even burn oil for awhile :D :D

Also its fine to break in a motor on syn. it takes longer for the rings to seal due to the anti wear of the syn...----------------------:D

use the merc hi perf stuff.

i have heard of some oil/additives resulting in some adverse clutch issues...what oil or what issues i am not exactly for sure.

i would only feel comfortable recommending the merc and royal purple oils due to (personal)extensive lab testing...we've also done our fair share of real world testing in various race environments.

don't fool yourself...if it looks, smells, or feels ANY DIFFERENT what-so-ever from new......it HAS been compromised.....CHANGE it even if it is synthetic!

Joey and Bobby,
 

Thanks for the info. Now I'm a bit worried. I hope the guy at least knows how to do a rebuild!

Guess I'll find out soon.

audacity,

I know you've done extensive testing and stuff, but I've been told that while Merc Hi-Perf is synthetic, it uses a different base composition for the simple reason that it will absorb water and still perform. This was a requirement of the Merc spec cause not everybody changes drive lube as often as us guys and they didn't want the headaches of water intrusion warranty concerns.

The water-absorbing makeup gives up some desirable qualities in order to get it to absorb the water.

Feel free to correct me if I am mistaken. We are all here to learn.

this may very well be the truth about merc lube!!!

all synthetics are not the same!

for me this would be a 100% moot point...we change the oil every weekend, even on our pleasure boat...we always pull the top cap off the drive to inspect as well...very easy to do and it speeds the oil change up big time.

M1 in everything, never a problem. Some new cars come with synthetics, the Vette is one.

Great thread. The "OIL" issue has allways been a good one. I have been researching the synthetic oil issue for a while and think that is the way to go for my engines. I have pre-lubers to help with the long down time beween starts. This post by Audacity does make me question using sythetic in my drives

I don't mind changing the oil in the outdrive ever 25 hours with the engine oil........but after every time we take the boat out........that is just not practicle.

Sounds like I should stick with the Merc oil for the drives.

What I was told is that Synthetic oil may allow the bearings on High HP blower motors to "slide" rather then "roll" creating flat spots on the bearings.....

MODVP

The only rolling-element bearings in an auto/marine I/O engine are the roller lifters and roller rockers (if it has them).

Those bearings will be under the same loads and conditions in a blower motor as they would be in a NA motor.

As far as roller lifters flatspotting, the Heavier or Thicker the lube film, the higher the chance of stalling the roller. AND it is more apt to occur at low rpm with heavy lube in a cold motor. One of synthetics' biggest advantages is its resistance to cold weather thickening.

The tips on roller rockers have been shown by high speed camera to either "not roll", or "roll backwards" at certain rpm. This behavior is more due to harmonics in a dynamic spring-loaded condition (think of those Gee Haw sticks where you make the propellor spin different directions) than any sort of lube film breakdown.

I notice your name MODVPSST. Your Merc outboards have rolling-element bearings all over them. The crank bearings, the rod bearings, all of them. I would recommend synthetic non-castor 2 stroke lube for you to run in them as well.

Lubricants are always a great topic! I will try to comment on a conversation I had with GM lubricant product specialist, actually she had her phd and was provided to speak at a customer's meeting where many oem were asked to make lubricant presentations/recomednations. She has writen a few papers and are all way above the layman's level of comprehension. One of the main reasons she felt synthetics were of a benefit in passenger car operation was that the oil has the ability to "re-juvenate" itself, at least in her reference to Mobil1. Apparently when a normal crude oil takes on moisture some degree of permanent damage occurs to the additives in the oil. As I recall, with Mobil 1 the damage is not permanent. There were other benefits also associated with the Mobil 1 where she advised me that in my high performance application it would be worthwhile to make the switch...and I have. As a side note, the intent of my questioning was not to obtain her opinion on the best synthetic but rather comparing Mobil 1 to crudes.

Bob,
She must've been pretty hot, eh?

MC.... What you say certainly makes sense.... I am relating what my engine builder has told/shown me... I do use Mobil 1 in my HP500.... I use a product from Alisyn for my 2-stroke... for anyone interested they have a website Alisyn.com & I highly recomend thier gear lubes as well as thier 2-stroke product... Take a look Alisynlubricants.com... I think... it might be Alisyn.com... I'll check.... but thier good people & I can't say enough about thier gear lub's....

http://www.aerospacelubricants.com/

Thats the website... sorry for the confussion.....

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Very true MCOLLINSTN and thank you,,syn.are truly the way to go !!! :D :D

1400-1500 hours, 4.3l no rebuild, everything stock, drive the crap out of it. Most of the time it is above 4k. Actually, the only time below 4k is through the no wake zones(I had it up to 5900 in a no wake zone once though, we were seeing how high it could go!!). Oil is regular merc stuff, changed every April. Regular oil is fine. If you are making lots of power, you might make a few more ponies by switching to synthetics.

Every time one of these oil debates come up I read them intently to try and find the best answer to the question as to which oil is the best to use. Some use synthetic, some use regular, some the red stuff others the purple. And what about grades? Straight or multi? Everyone seems to have a different answer and everyone records some fantastic results. An engine builder told me not to use synthetics in my blower motors because if I get condensation in the motors I won’t know it because the synthetics are water rejecting. At least with regular oil if I see my oil turn into a milk shake I know I have a problem and can do something about it before I trash a motor. This sounded good but others say no.

How about just using what the engine manufacture recommends? Could there be some wisdom in his recommendations or are we all just a little bit smarter than he is?

Quiet, corvettes and vipers ect. come with mobile 1 that should help you some with your choice also put alittle water in a 3.99 bottle of mobile 1 , and tell me again it doesnt mix ,,,it does for sure ( I tried today,,bored ) again your engine builder is in the 70's,,,,,, syn. are even used in piston turbo air planes talk about condensation from 50 on the ground to 30 below at altitude under boost ,I use aeroshell and have it oil lab checked every time with great results ,,aircraft oils man difference is lack of ash for spark knock protection ,please use syn. its great and used in about every type racing you can name ,blown,turboed,ect.:D :D :D

I've run Redline Heavy shockproof in my Bravos from day 1, 1996. Broke my first and only drive in summer of 2000, this is on a 41 Velocity with 600s. Took two teeth off the pinion gear.

All motor oils are formulated to coexist with a certain amount of water, synthetic or otherwise. Condensation is a very real and very well-known part of an auto engine's environment. The water issue is a non-issue when discussing motor oil.

Gear oil is a different story. Some gear oils will suspend water, others reject water. This is true of conventionals and synthetics both.

Mercruiser specs their gear lubes to absorb water better than others. This is a plus if you go long intervals before changing gear lube. It is also a plus if you wrap lots of fishing line around your propshaft (kills the seals).

I'd rather use the lube that gives the best chance for my Bravo to live. If that means keeping an eye out for water and changing more often, then that's fine with me.

keep in mind that water is result of combustion kids.

funny,,,,,there is so much $$$ and politics in oil as well as auotomotive industry....kinda makes it very hard to find the truth.

Mobil 1 15-50, but don't drip it in the bilge

Syn. Oil is a ***** to clean...

I run Amsoil,& use Napa Racing Filter's we do change it quiet frequently..so far so good.and after 2 season's of running hard & proper maintance.. i suppose any syn..oil will do. i run 2 10.71 littlefield blower's. not to say the engine's haven't let go. They have. but not from the oil.

Psttttt..Spray it with purple stuff "degreaser" that will clean it quick.. just don't let it hit anything that has been powdercoated.. or you will---->>@%&*#%.

I run Amsoil,& use Napa Racing Filter's we do change it quiet frequently..so far so good.and after 2 season's of running hard & proper maintance.. i suppose any syn..oil will do. i run 2 10.71 littlefield blower's. not to say the engine's haven't let go. They have. but not from the oil.

How many here have ever had a engine failure related to oil composition or breakdown? Just curious.

Amsoil is the best !!!!

True that synthetics can agitate an already leaking engine but they do work better. I like Mobil 1 myself. It is the only oil that would keep my turbo bearing clean. Another interesting thing I learned. I tried Pro-Long engine treatment in my turbo car and noticed how much cleaner my oil return line was. I never was one for oil additives but I was pleasantly surprised by Pro-Long.

Roby

i have ran two trucks to over 300k with valvoline conventional oil with no problems so I just cant justify the extra expense but i do change my oil overy 3k miles and twice a summer on the boat.

CEN-PE-CO

Mobil 1 all the way.
Even the mower runs on it.

I'ved used it in my old Bronco II for 100K+ miles, the wifes old Dodge Daytona Shelby Turbo for 110K+ miles, my current truck for 70K and the wifes new Mustang for 13K.
No trouble what so ever.
I even used Mobil Synthetic ATF in my truck when I changed the fluid last time. That was expensive. Fourteen quarts cost me 45-50 bucks.

Most everything I've seen on this subject revolves around how often you normally change your oil. Consensus of everything is if you change it on time conventional is just a good. If you're prone to going long on changes, then synthetic helps because it takes longer to break down. Other than that it's the "feel good factor".
Personally I use a blend in the engine (compromise okay?) and full-synthetic in the drive "only" because of it's tolerance to heat exceeds conventional drive oil before breakdown....If you want to feel good, spend away...

Amsoil of course :rolleyes: :rolleyes: :rolleyes: