Synthetics ... when to switch

[Saleen367]

Alright ... can't see spending the same amount of money on Merc oil when I can get Mobil 1 for the same price. :roll:

I am nearing my 20 hour oil change and would like to use the Mobil 1 for the change. :mrgreen:

However, being a gear head for way too many years, I know that the rings should be seated before switching.

Will 20 hours be enough or no? I have to think yes.

Opinions? [smilie=042.gif]

[simulatedjim]

To add to the question; would using a synthetic blend before going full synthetic be good or bad?

[mnoutlaw]

Depending on how much idle time you have, you should be good to go. Get Amsoil Serie 2000 20w-50 or Royal Purples straight 40w. Save the Mobil for the Walmart shoppers.

[GrumpyBullet]

AMSOIL VS MOBIL 1 http://www.synthetic-oil-tech.com/d.cgi/1225987/articles/amsoil_vs_mobil1.htm :mrgreen:

[Saleen367]

OK guys ... tell me why to run the 2000 Series 20W-50 instead of the Marine 15W-40?

I'll put the Mobil 1 in the F150 if you can convince me why the Amsoil is worth the added expense.
[smilie=042.gif]

[mnoutlaw]

Marine 15w-40 was made for ALL Marine and Diesel's engines. Series 2000 was designed for racing motors, the ones that run 5000-7000 rpm's for hours at a time. I put the 20w-50 in the boat at the beginning of the year and haven't changed it yet. I tried using Mercruiser and Mobil 1 last year and both broke down around 10-15 hours. By broke down I mean my oil pressure started dropping to 5-10 psi after a hard runs. The Amsoil has yet to let my oil pressure go below 20 psi, they have 50 hours on them already this summer and both motor have used less than 2 quart each, not bad for oil burning forged pistol 502's. Haven't tried Royal Purple yet but I have two cases of 40w in the garage. I see allot of people recommending the straight weight for marine motors since they run a pretty steady temperature and it's also printed on the Mercruiser 525 EFI's data plate.

There was a lot of talk on this subject on Teambajamarine site. The guy from Zigouras Racing said all he uses is Amsoil 20w-50.

[Saleen367]

OK ... being the cheap azz I am, I needed to know.

Understand all about the stress of continued high RPM use and what comes with it. Raced cars many years. Used http://www.redlineoil.com/products_motoroil.asp?pvID=64&prodID=46&subcatID=15 products in those and thought highly of them. However, Redlines race oils do not provide a detergent.

I'm admittedly not familiar with Amsoil products and was wondering why they have a marine specific oil and you don't use it.
Can't help but wonder if the Series 2000 is a safety net vs. legitimate need for a stock engine.

Maybe if you saw how we use our boat you would know why I questioned it. :roll:

Think of my Outlaw as a 30' Sundancer with color and no room. Rarely sees the high side of 4000 RPM. But an occasional blast to 4800 is a Bi-weekly occurance. Lots of cruising between 3000 - 3400 RPM. [smilie=schla08.gif]

I see your point though. Cheap insurance at $32 gal. [smilie=042.gif]

[Saleen367]

By broke down I mean my oil pressure started dropping to 5-10 psi after a hard runs.

That's downright spooky. :shock:

I personnally believe that the 45 psi I see under power is insufficient.

I'm used to running 65 - 80 psi in my enignes.

[JMS]

By broke down I mean my oil pressure started dropping to 5-10 psi after a hard runs.

That's downright spooky. :shock:

I personnally believe that the 45 psi I see under power is insufficient.

I'm used to running 65 - 80 psi in my enignes.

JMO, In my racing days I talked to many high $$$ engine builders. At the time their engines cost in excess of $60K. Their theory was, with todays more highly precise machining equipment and the ability to machine to closer tolerances that the mind set of old does not apply. More oil pressure is not necessarily better. Higher oil pressure causes more internal friction, more drag, higher oil consumption, more rapid engine wear and robs the engine of horsepower. Their rule of thumb was 10 psi for every 1000 rpm with a max pressure of 40-45 psi. This pressure provides all the lubrication you need. To further prove this point todays automobiles are running lighter and lighter weight oils, produce more power, and last longer than their ancient counterparts. Most vehicles today are using 5w30 motor oil. Some are even using 5w20 and some of the new Honda's are using 0w5 weight oils. Again this is JMO :mrgreen:

[HiTechRedNeck]

most nascar teams don't run much over 25 psi. That high oil pressure rob's power. They seem to be able to make them last. As for your first question, I would say 20 hours is plenty of time to change to synth. As for weight, the thinner the oil the quicker you get oil pressure at start up, and much less wear. That is most of the theory behind the thinner weights. As far as synth vs. straight, in the same weights we saw no difference on the dyno, but in the long term synth wear is certianly less and the synth last longer. A guy could right a book about all this, just something to think about. I run 10-30 valvoline for break-in and 10-40 mobil 1 after in a pair of 600 hp 498 CU motors. JAO

[Saleen367]

Seems everyone has differing opinions on oil. Which in a way is good. Means a lot of stuff is working for everyone. And yeah, a book could be written.

As far as NASCAR engines, they get tore down after 400-500 miles, so I can see why they want less drag, but those are hand built engines. I'm sure they have done their homework on the dyno.

I was running the high pressure as insurance for my 7500 RPM supercharged engine. (road race)

As for oil weights, I totally agree with less is better. Having said that, these engines that Merc is using are old technology vs some of the newer auto engines which are multi cam, multi valve engines. Having 4 cams and 2 - 3 times the valvetrain components is an oiling nightmare. It's critical that oil is available immediately upon startup with most modern engines. Not so much with these GM units. JMO

Thanks for all the input here guys!

[JS2FST]

I couldn't because my cousin who is a chemist for Mobil says he wouldn't use any full synthetics in anything.

[Saleen367]

Ask your cousin about their new 20w-50 V-Twin oil. Superior qualities to anything else out there. [smilie=061.gif]

Read about it here:

http://www.offshoreonly.com/forums/showthread.php?t=83930&page=1&pp=30

[Caincando1]

Oh man there are so many different theories on oil. Jeff to answer you question regarding the added expense of Amsoil or Royal purple. Well in a nut shell they are completely different oil that the other synthetics. Seem the other are actually petroleum based then turned into a group 3 synthetic. Amsoil and Royal Purple are a group 4( I could be wrong on the group) and are a true synthetic. There was a huge court battle over this. Because some oil company where calling then synthetics when they are actually petro based. This is much cheaper to product hence the price difference.

It can all be found on this web page. http://www.bobistheoilguy.com/

[meyerwrench]

Here is my [smilie=twocents.gif] If your engine has roller lifters I woud stay away form synthetic oils because they lubricate so well that the rollers will quit spinning and just slide on the cam journals and cause flat spots on the rollers and then ruin the cam and lifter. The thicker oils will hang on to the bearings and cyliner walls longer to help reduce the dry start because boat engines sit so long wihtout being started.

[Saleen367]

OK Meyerwrench, if that's true, and I've heard it before, then why would Chevrolet ship the Vet from the factory with Mobil 1 in it? [smilie=265.gif] :mrgreen:

Something about that whole theory doesn't hold water IMO. :oops:

[meyerwrench]

The Corvette engine and other auto engines that come from the factory with synthetic oil are designed for that oil. Marine engines are not. I got my Power Boat mag in the mail on sat and there is a question from a guy in the Teague on Tech section you should read it. :shock:

[mnoutlaw]

OK, I used both Royal Purple and Amsoil and found little difference between them, unlike Mercruiser which both broke down within 10 hours and Mobil 1, which gave low idle oil pressures. I think I'm going to stick with the straight weight because my motors are not used in cold climate and run pretty consisant temperatures.

On are third trip to the Ozarks we had Royal Purple in the engines, no oil usage and max rpm's where achieved. Water and oil temperatures remained constant. And, it's cheaper at $4.95 per quart. We put on about 15 hours that trip.

In Mobil 1 defense it did come in our 94 Vette and we kept using it with no problems. It did over 160 mph on a regular basic.

And again, the purple bottles and oil match the boat!

[Saleen367]

OK, I used both Royal Purple and Amsoil and found little difference between them, unlike Mercruiser which both broke down within 10 hours and Mobil 1, which gave low idle oil pressures. I think I'm going to stick with the straight weight because my motors are not used in cold climate and run pretty consisant temperatures.


I gained 4 lbs @ idle and 3-4 lb at speed with Mobil 1.

[Saleen367]

The Corvette engine and other auto engines that come from the factory with synthetic oil are designed for that oil. Marine engines are not. I got my Power Boat mag in the mail on sat and there is a question from a guy in the Teague on Tech section you should read it. :shock:

You got any idea where a guy can get specific data on spring rates for these engines?
I've been building roller engines for years and have never had a problem with the rollers or cam lobes using synthetics.

Having said that, I also build Fords which probably accounts for the longevity. [smilie=042.gif] [smilie=071.gif]

How do you build a roller cam engine that is incompatible with synthetics?
Sounds to me that Teague is saying GM-Merc uses chit for valve springs.
My hydraulic roller engine in my Saleen sports 170 lb seat pressure and 345lb open, .588" lift, 230* duration in/ex. 6750 RPM and it will live forever. :mrgreen:

[Hell Ya!]

Here is my 2 cents, but it may not be worth that much. I prefer a straight weight like the 40W instead of the 20-50 multi grade. But let the engine come up to running temp for a while before running the piss out of it. Reason is multi grades have a parafin blending agent that can interfer with the ring seal at higher rpm's, and cause blow-by and compression loss / lost power, and also let oil go into the combustion area and result in oil burning. Even worse, detonation by killing the octane when it mixes with your fuel. Another point of interest may be, do either of these oils give a fuel contamination ratio?? I would never use an oil in my nitro engines that didn't have a fuel contamination ratio of at least 7%. This should be of importance, with all the idle areas we go through, that tend to let a lot of unburned fuel go into the oil. However that fuel contaminated oil will clean itself up on a long cruise above 3500 rpm when the oil gets some good heat in it , and it can boil the fuel out. But it is very important that the oil keeps its lubricity during the contaminated state.
As for oil psi. I like to see 20# at hot idle and around 55 to 60# at 5500 rpms. As JMS stated above, you don't need the high psi. it only stresses the oil pump and also makes the oil tend to run hotter, not to mentoin it is hard to return oil to the pan at high rpm, because of the windage from the crank and rotating assembly. If you are running too much oil psi and you pump it all into the valve covers and lifter valley durring a long hard high rpm run, you will surely smoke some rod bearings. It's a good idea to glance at the oil psi gauges when you know you are squeezing out the last drop of cherry juice your engines have left. If you see any fluctuation or descent of the needle get off the loud lever!!! If you think this is hard to see when you are bouncing over waves, put a drop of red paint on the gauge lense at your highest hot reading. This will make it easier to read at 230 mph + during tire shake. :twisted:

Sorry got carried away,,, :oops: Darn flashbacks!!!!! :lol:

[Hell Ya!]

FORDS!!!! Do you know where I can get a big block ford. My anchor won't hold on a windy day in Party Cove... [smilie=050.gif] JK

[Bajapit]

FORDS!!!! Do you know where I can get a big block ford. My anchor won't hold on a windy day in Party Cove... [smilie=050.gif] JK

You are a breath of fresh air. :mrgreen: :mrgreen: [smilie=071.gif]

[meyerwrench]

FORDS!!!! Do you know where I can get a big block ford. My anchor won't hold on a windy day in Party Cove... [smilie=050.gif] JKI would just use a Box Anchor. They are better built and a little bit heavier. Plus you won't need to use any chain roe to get it to set. [smilie=071.gif] JK Ford guys.

[Bajapit]

FORDS!!!! Do you know where I can get a big block ford. My anchor won't hold on a windy day in Party Cove... [smilie=050.gif] JKI would just use a Box Anchor. They are better built and a little bit heavier. Plus you won't need to use any chain roe to get it to set. [smilie=071.gif] JK Ford guys. :mrgreen: :mrgreen: :lol: [smilie=071.gif]

[mnoutlaw]

Wow, where's the love!

[Saleen367]

What love? :roll:

I used the "F" word and this is what I get. :shock:

Wonder what Dodge would bring? [smilie=011.gif] :mrgreen:

[outlawed racing]

You arent supposed to use synthetic oil in a roller motor period!
I would make sure you know what you are doing, you can ruin the lobes on your cam and cause other damage with synthetic oil in the wrong application. This has been discussed and documented in many publications like Powerboat etc.
Mercruiser does not recommend synthetic oil in a 500 hp for example!

Straight 40W is also what is stamped on a HP500 if you arent going to use the manufacturers oil, also says it in the manual.
Many manuals also prohibit synthetic oil!