odurandina

thanks,


i hope everyone took the time to read Bob's oil page. don't believe what he's saying ?


ask the Mobil 1 engineers, they nailed it 25 years ago. and they're ALL on the same page.


now you got an engine sitting out all night, and it's 40 degrees. and you're running 20w-50 in there.


that's a bone dry engine at startup. that's what ALL the engineers are saying is actually going on.


that's got to be way WAY worse than a little blowby in a 25 year old car running synthetic 0w-40 oil.



http://www.bobistheoilguy.com/cms/

theedge

I always find these threads funny. I have run my car on 20W50 in colder temps than many people on this forum have ever been in nevermind drove their Porsches in, and it started fine and drove fine. These engines and thin oil do not go together. Period.

odurandina

synthetic 15w-50 then ? what brand of oil ?

JnJNY

Just a suggestion... Read the posts and information on bobtheoilguy carefully.

Mobil 1 is not the same as it was... Many will agree that Mobil now has it wrong 25 years later. As many of their oils shear down very quickly...

Bobtheoilguy is great if you take the information of UOA's and VOA's and see how it applies to you and your car and use of said car.

odurandina

i have 2 ford escapes in Mazatlan, where i will be back this winter i've been running Valvoline 5w-20 oil in those two trucks, taking them off-road for about 7 years. got 148 k miles on one of them now and 155 k on the other. they barely burn any oil. (the engines make good power as i'm not running cats). this has contributed to my bias about Bob's favorite synthetic 0w-30 oils... but these are 24 valve Mazda engines.



i believe what you guys say about Porsches.

944Ross

BS! I opened up my '52's engine after it had sat for 12 yrs or more, popped the rod and main bearings, and all were well-oiled. There is NO WAY all the oil leaves the bearings and other lubricated parts after an overnight rest.

Please, please give the crap about primary and secondary imbalance forces a rest, it has NOTHING to do with lubrication. Those forces pale in comparison to the loads on rod and crank due to power strokes, and have been well managed since the early '30's when Chrysler introduced Floating Power engine mounts.

PS, the 968 motor is NOT the largest 4-banger ever built for cars (Model A's were 201 ci / 3.3L), and if you include industrial engines it's so far down the list it isn't worth mentioning. FedEx trucks with the Cummins 4BT diesel engine are a 3.9L 4-banger, they seem to do alright for a flawed design.

odurandina

according to Bob:


"...Some people have said they use thicker oils because they only use their cars every 2, 3 or 4 weeks. They are afraid that thin oils will fall off the engine parts and result in a lack of lubrication at startup.... oil on the surface of parts does not lubricate. It is the FLOW of oil between parts that lubricates...."




according to Bob a 30 weight synthetic is even heavier than a 10w-40 conventional mineral-based oil:


"This is worth repeating: The synthetic 10W-30 grade oil is based on a heavier 30 grade oil while the mineral based 10W-30 oil is based on a thinner 10 grade oil. They are both similar at operating temperatures yet the 30 grade based synthetic is actually less thick at startup and much less honey-like at low temperatures. This is the opposite of what common sense dictates...."





"It seems that many engines work best with multi-grade 30 weight grade oils. Others would do better with a 20 grade oil and few would require a 40 grade oil. You can only determine what is best by experimenting. Admittedly I did not think my Ferrari Maranello would need a 20 grade oil. In truth I could actually have used a 10 grade oil. A 0W-10 would be good but it simply does not exist for normal use. Red Line does make 2W, 5W and 10W oils (this acts as a 0W-10 multi-grade oil) but they are for racing only. One Formula 1 team has actually used these very oils off the shelf from Red Line."




that seems pretty wild. and then Bob goes racing:


http://www.bobistheoilguy.com/cms/in...=article&id=79







.

944Ross

My objection was to the characterization of a cold morning start as being a "dry start". And FWIW, I'm going to disagree with Bob, presence of oil IS lubrication -- maybe not hydrodynamic conditions to fully float a rod/main bearing, but it is not a "dry start".

333pg333

There's a lot of crap in this thread, but then again no surprises either.

For those of you who haven't seen this thread, it is the best for our cars. Contributions from experts in the field. Not obtuse cutters and pasters.

http://forums.pelicanparts.com/porsc...4-sm-oils.html

odurandina

that's a very good link. thanks for posting.


i'll run Mobil 1 0w-40 this winter.


my Porsche tech is Gerry at European Performance Engineering in Natick, Mass.


he put that oil in my car last winter. it's not chopped liver. i'm not racing. it's a 40 weight oil that flows at startup in the extreme cold. not saying that's what you all should run. but i trust Gerry. he's got the largest shop in New England, (google). he's rebuilt enough Porsche engines over the past 25 years to get us to the moon and back. the guys from Germany consult with him often. he's been involved with trying to sort out some major problems with the Cayman. he's a PCA guy, races what he builds, fixes what other people destroy.


he likes that oil for our extremely cold weather, and Mobil 1 15w-40 or 15w-50 (if you drive really hard) for summer.


that's probably what i'll do in the next couple of years. we'll see if my engine stays together.


it's getting time to do the rod bearings, so that will probably be done next summer.


i put down huge miles daily driving this car, and i won't lose any sleep running the thinner oil during the winter.

elzergone

well, I do have to say you're pretty brave for taking a ford escape off road.

odurandina

the ford escapes have been driven underwater.


i run 1.5 inch donuts under the springs and 235 75 16 Goodrich Mud Terrain tires.


they are both very good trucks. unfortunately, i've been stuck in the mud, stuck on the beach, railroad tracks, (had to stop a high speed freight train and got an 800 dollar bill from FERROMEX for holding up a mile long train), been stuck on the beach, fallen into sinkholes. had the alternator die 20 miles down a dirt road in the sierra (agua caliente, sinaloa).

..

very stressful when the tide's coming in during a big swell and you're stuck.

odurandina

ran the car VERY hard today from ____ towards Chicago.


me and a beemer tore it up. 85-115 MPH. all day.


almost wished i hadn't changed to the 0w-40 winter oil until next week.

Chubbs

I don't normally bother posting in these kinds of threads, but there is a lot of misinformation afoot in here.
First, torque is a product of a lot of things, but layout isn't really one of them. Crank throw, bore, stroke, rod ratio, cams, manifold volume/runner length, etc. are what determine torque. Torque doesn't magically increase or decrease solely as a function of the motor layout. Besides, if torque was the goal, all cars would have straight sixes. The large main bearing surface area, coupled with the good vibration characteristics would (and does, look at mack trucks) make them an excellent candidate for torquey motors. The reason 4's are so popular is the combination of design goals. They are small, have enough main bearing area, are reasonably smooth (enough to get the job done), are economical to manufacture, and aren't prone to torsional vibrations through the crankshaft which would otherwise prevent sustained high RPM use.

Second, if vibrations are a concern, few people would propose the use of a V8, flat plane or crossplane.

Here, read this:
http://en.wikipedia.org/wiki/Engine_balance

Chubbs

[QUOTE=944Ross;7957131.

Please, please give the crap about primary and secondary imbalance forces a rest, it has NOTHING to do with lubrication. Those forces pale in comparison to the loads on rod and crank due to power strokes, and have been well managed since the early '30's when Chrysler introduced Floating Power engine mounts.
QUOTE]

You're right. However, even the load due to combustion is small in comparison to the load due to high RPM use (except when lugging the motor). Even a motor that isn't under load will have high stress at high RPM's as a function of the mass of the rotating assembly. It takes force to change the direction of the pistons (and roughly half the mass of the rod), and it's doing it quite fast. (F=M*A)