I do not know if it's been posted here before but I thought this video would be really helpful for people that want to visually understand how the bearing operates and why it may fail...20m clip but the first 12m or so is really what you need!

 

Anxiously waiting for Jake's reply

 

There's our buddy Pedro!

 

Never argue with a fool... The people standing around won't know which one is which.

 

"Never argue with a fool... The people standing around won't know which one is which."

 

Very informative video, and great job explaining in terms that anyone can understand. He'd get my business in a heartbeat if he was local. How does the oil stay circulating?

 

I like when people can talk and work problems out with each other...

I would always respect someone's opinions as long as they are cordial and make sense to me...

I am not an engineer, yet I can follow and understand what Mr. Pedro and what Mr. Jake are talking about. I have a new updated bearing in my "Refreshed" motor and hopefully will not need Mr. Pedro's or Mr. Jake's products for a while. When the time comes for a preventative item or a whole new setup I hope the discourse is still going on since it will only cause the products to evolve and get better.

Rant off...

 

I don't know Jake personally, I do know Pedro. Nice guy. That said the DOF makes no sense to me because the same centrifugal force that he claims causes the bearing to shed oil from splash/immersion will also repel a stream of oil sprayed at the spinning bearing.

 

While I'm not a fan of the DOF (or other IMSB solutions), while the spinning bearing will throw off/shed oil the oil stream is continuous. At something like 60psi oil will get to the bearing.

 

Then consider aeration, and how that comes into play engine- wide.

 

Here is a link that has a $/time comparison chart at the bottom. For the same price as The DOF TuneRS/Pedro product ,you can get the LN Single Row Pro.
Don't forget to add the cost of special tools.
http://www.thepopularmechanic.com/Po...MSOptions.html

 

seems pretty logical and good solution.

 

I'm an EE, not a ME, but I've been around moving, flinging, flying, noisy things for pretty much all my life since I was 10 and built my first go cart with a mower engine. In that time, it's been my experience that there's never only a single way to engineer something.

This is true in my field previous of nuclear engineering. We have a pressurized water reactor, and a boiling water reactor. We had Fat Man which was implosion of shaped charge, and Little Boy which was a gun type critical mass, we have U fired plants, and Pu fired plants for differing reasons. They all do the job as designed, and some ways are better than others. In my current field we are well known for our technology, but honestly, our competitors product will get the job done. Maybe not as fast, but it'll get done.

Sad to see a respected member of the 996 community bad-mouthing the competition. Extra sad because the engineering of the oil feed system looks very sound to me. We've been oiling bearings, journals, and the like for many, many years and all the fuss about the ancillary effects of the oiling process are like stray neutrons in the reactor. Meh - stuff happens.

Does the DOF divert too much oil for the bearing that engine lube is compromised? Hell no.
Does the DOF exacerbate air entrainment/foaming of the oil? Possibly, but looking at the discharge orifice, gee, how much oil is going through there, and how much of that oil is being aereated? Doesn't look like much in a system that uses about 8 quarts?
Does the DOF cause the existing bearing to wear quicker? Hell no.
Is there skidding/flat-spotting of the ball in the race? I don't know, but if there is, show it to me.

No one has a lock on engineering. If this product doesn't do what it is sold for, it'll start failing prematurely, and then you can show me some data. But - predicting failure modes? Yah - you should have been at Porsche when the first IMS was designed so you could predict that one. uh-huh.

If I have a 996 in the future, I sure would consider the DOF, it looks elegant to me, and the cost is reasonable considering the alternative situation of a blown engine. BTW, I have no affiliation with DOF, or whatever their name is.

<edit: I just remembered something, if aeration is a problem, then the engine is fitted with an AOS right? As long as the system is working, and the vent is at the right pressure, that should not be overwhelmed by this small amount of added jetted oil.>

 

Lotta info here, very informative for all 996 owners!

 

The factory AOS isn't there to handle foamy oil, its placed in a position where it helps to reduce airborne mist and vapors, and is fitted as an emissions control device. If the AOS wasn't there, a road draft tube or catch can would be fitted, neither of which are environmentally friendly.

The devices in the engine that are fitted to assist in the control of aerated oil are the swirl pots. These are fed with oil from the secondary oiling system and direct oil thats gathered by the scavenge pumps located in each cylinder head, back to the sump. This is done by passing the oil through a series of circuits in the crankcase, where the oil passages meet at the parting line of each case half. From there the oil passes through a pair of swirl pots with a tangential flow thats designed to reduce aeration as the oil falls from suspension within the swirl pot. When the oil completes this cycle it is fed back into the sump, where it is hopefully de-aerated.

The issue with this is the factory system is marginal at best and isn't adequate at hi RPM, as I have proven in a series of studies as I work to develop lubricants with Joe Gibbs Driven, where creating oils that resist aeration is always a primary objective of development. To further prove that the system wasn't adequate, Porsche swapped to a different design with the Gen 1 Cayman, and then a year later in the 997. This design creates a tangent of flow that utilizes the entire sump to act as a swirl pot, giving the oil further to fall from suspension, as well as entering the sump on the outer perimeter, furthest from the oil pick up tube. Porsche doesn't make changes unless they are required, changes cost money.

The 997 system isn't much better and also hardly controls aeration. In 2007 when I was working with uncontrolled oiling of radial components within the M97 engine, I learned the hard way about aeration and what it will do.I learned that adding anything to these engines that further promotes aeration will overload the early de-aeration system quite easily, while the later system has a slightly larger margin of error.

Lots of the issues that we deal with from track engines (DE and AX) are directly attributed to aerated oil and the loss of film strength that it has. When an engine has every component that uses boundary layer protection worn, it does;t take a rocket scientist to figure out that aeration and a loss of film strength was the common denominator.

I abandoned "project spray" in mid 2007 due to aeration concerns, but the one mistake that I made was not Patenting it. People knew I was working on it, but Iu didn't care, because at that time we hadn't perfected the IMSR procedure for dual row IMSB extraction and I was trying everything I could, to keep the bearing in the shaft, but still keep it alive. Just after that someone else in Puerto Rico posted a picture of the same arrangement on a Porsche Technicians newsgroup, but mum was the word from me. Then in 2012 a fellow over on Pelican posted the exact same product in an extensive thread. I watched that thread closely and I did admire his inventiveness. A few months later, here came a "new" product from the opposite side of the country..

Keep in mind that it is claimed that the real issue behind IMSB failure is lubrication. I don't agree with this for many reasons, and primarily this is why:
The dual row IMSB requires 90% more oil volume to run cool and to reduce wear over the single row IMSB. If lubrication is the real issue, why aren't the failure tables turned with the factory admitting to 8% failure of dual row IMSBs rather than singles? Fact is the 8% failure rate is for single row bearings, not for dual row bearings. If the lubrication only hypothesis is correct we should see more dual row bearing failures than singles, because they require 90% more oil to keep the cool and lubricated. That said, the second row of bearings is deeper within the shaft housing, and operating behind another row of bearings, so why don't we see spalling and race erosion on the inner race of the dual row bearing than the outer race? Thats easy, because the issue isn't lubrication; the issue is load. The dual row bearing carries 1/2 as much load per row of *****/ races than the single row, which is why single row bearings fail more frequently.

Back in 2013 I paid for some time with an Electron Microscope to survey some races and ***** between single and dual row engines with the same miles on them, and the differences were staggering. These photos were taken for use in my book.

The smaller orifice is part of the issue. The smaller passage allows the oil to spray in lower volumes, but with higher pressure, which aggravates aeration even more.

The oil is spraying from the flange onto a radial component (IMSB) . Its not just that the oil is spraying, but that its spraying onto that rotating surface that creates further aeration.

Lets back up a second. What did I say? My quote was basically stating that I'd not enter into any arguments on the topic, because its foolish. My next statement said "consider aeration". I made the first statement after another poster tried to instigate a "Rabid response" from me.

I don't sell a single IMSR product to the open market, and haven't since 2011. Once my development work is done, I collect my portion and check out. Pedro, or anyone else isn't my competitor; because I have no product to sell. In fact when I carry out IMSR procedures here I have to buy the products from the same distribution that every other shop in the country does.

No, I do not agree with the video, but if people want to listen to it, thats their prerogative. I should do my own version of that video, but I have put all my info into my book, and don't need youtube to feel like a Super Hero.