Does anyone know the reason why the DOF is not recommended to be used with the LN bearings.

 

Basically, it is manufactured by a competitor so L+N will not endorse the DOF, if you search on here you will come across their view on the system and why they don't like it.

 

^This^ at least that's how it seems...

 

So there is no mechanical reason why a DOF would be bad to add to an LN bearing already installed? Maybe there is more to this than just competitive systems. It seems like the best of both worlds would be to have the LN bearing with oil squirting on it if you couldn't have the IMS solution. On the other hand there has never been an LN bearing failure that Jakes shop has installed and the DOF probably isn't necessary but
I am curious about what it could hurt if anything.

 

In theory you could turn this issue around - chose whatever ABEC/ISO grade of 6204 bearing(If it is a single row car) you want and use the TuneRS DOF kit . No need to use the bearing TuneRS supply.The bearing they supply is a generic $2 part.
An upgrade to an ABEC 5 ,6204 bearing is less than $4 or upgrade to ceramic+stainless for $75 :-).Just search on EBay for 6204+2RS ABEC+5 or 6204+2RS+ceramic si3N4.
http://www.ebay.com/itm/Yamaha-Snowm...item1e510d9323
http://www.ebay.com/itm/NACHI-6204-2...item258550962a
or this rated at 900 degrees !
http://www.ebay.com/itm/6204-High-Te...item1e50a63aff
You could say the TuneRs oil supply is unnecessary/vulnerable but it is difficult to conceive why it could be any worse than an upgraded OEM bearing with no external oil supply.The effect on the oil supply volume/pressure to the camshafts has been extensively discussed in other threads and did not seem to be a problem. Time will tell. The TuneRs system does require 'chopping' out a small piece of redundant flange. Not difficult.
It would help tremendously if those who know the reasons the TuneRS system is bad, would explain them.Otherwise we are doomed to have these faith-based IMSB discussions eternally.

 

There must be mechanical reason why Jake does not recommend using a direct oil feed to his bearings and I wish someone would tell me the answer.

 

Ask him.

 

Jake reads these posts regularly, if he wants to tell us he will and if he doesn't he wont. Maybe I will call him and ask if he or nobody else answers the question. That still doesn't mean I'll get an answer.

 

Fascinating discussion on this very topic here:
http://www.renntech.org/forums/topic...il-feed/page-2

 

I just read the above posted link in its entirety. Plenty of opinions but nothing cut and dry. I am glad I got Jakes fix in my car and am happy with the results and the FACT that none of his installs has ever failed. I will always be curious about the DOF and until many more users of it have had it for many years it will be another unproved but possibly fine option.

 

Seems pretty cut/dry to me.

From post #31 of the referenced thread:

Thank you for your photo Pedro. The last photo shows exactly why you cannot use the DOF with the LN kit.

There is not enough thread engagement for the center nut with the DOF and the center bearing support in the LN Engineering IMS Retrofit. Installing one with insufficient thread engagement will not allow you to accurately torque the center nut. And even if you do manage to torque it, with subsequent heat cycles the top threads will likely not hold the torque. We've already determined an improperly torqued center nut - either too tight or loose will cause a failure! I hope for your sake there aren't many out there like this.

Additionally, we closely measure and blueprint (and have so for several years) to ensure proper fitment. How does someone installing the DOF know that the flange provided is made to the same specifications as the LN Engineering IMS flange?

Lastly, how can the DOF be compatible with both the stock center stud and LN Engineering stud since they seal in different manners. Our center stud is ground to a precise dimension to ensure leak free operation with the internal o-ring located in the flange. Stock flange relies on a larger o-ring located on the center stud. Lack of an internal o-ring will result in leaks over the long term. We also know this for first hand experience where users damaged the internal o-ring or accidentally removed it. Even with loctite and flange sealant, they will eventually leak and cause a comeback. Again, first hand experience.

 

I think Pedro replied in a later post they provide a different flange customed for LN bearing so the stud will fit properly.

OP, my understanding of the alleged mechanical issues are:

1) the location (the head) where DOF tap for oil which may affect oil pressure and flow on that bank, which in turn could affect timing chain tensioner pressure and variocam operation. Note JR tap the oil for the IMS solution from the oil filter with the LN spin on adaptor, the main oil supply source as opposed tapping from one of the branches.

2) friction on the bearing with too much oil. I got this info from a retired bearing engineer. Of course the extra heat will be cooled down by the oil flow. Nonetheless, it consumes extra power of the engine and raises the oil temp.

 

I must admit that I am thinking of an upgrated standard bearing and DOF when I do my clutch, if the standard bearing is 95% safe (based on the 5% over rated failure rate) in normal conditions, and all that I have heard of that are replace have the grease washed out even when they havent failed, surly the DOF makes it pretty much foolproof.

 

Well, the problem with that then is the LN solution is not fitted to the engine as it was envisioned at the LN factory during the design phase/test phase.

The LN installation then becomes a hybrid. It makes sense that LN would therefore not support its bearing with the DOF fitted.

As for the concern about too much oil, there may be an issue with the bearing churning the oil and increasing its temperature.

There is the real possibility of another problem arising from too much oil.

The *****/rollers of rolling element bearings must actually roll. They can't slip or slide. To this end the bearing lube and how the lube is supplied is specially designed so the bearing *****/rollers do not slide, but always roll. In some high speed gear boxes -- machine tool bear boxes for instance -- the lubrication at some point, as the speed of rotation rises -- transitions from a fluid to a mist to avoid over lubing the roller element bearings at their higher speeds.

The issue I believe with this DOF is this can over oil the bearing and the concern is the bearing *****/rollers slide on a thin film of oil rather than roll through it. The sliding if it occurs can't continue indefinitely and the oil film breaks down the ball/roller then makes metal to metal contact with the race but if the bearing ball/roller is not turning at the same speed there is an instant of metal to metal contact that over time can result in exceptional wear and tear of the bearing which then can lead to premature failure of the bearing.

The bearing *****/rollers and the race in which they reside is similar in some respects the tires of an air craft and the pavement of the landing strip when a plane lands. The tires are of course stationary but have to come up to the proper rotational speed in just a fraction of a second. We have all seen the puff of tire smoke and hear the tire noise watching planes land. In some respects this happens inside the bearing if the rolling elements stop rolling and instead slip/slide then of course resume their rolling at some point.

 

I find all these theories fascinating, they all sound correct depending on who is explaining them. For me it always comes back to they are mostly theories or opinions. I've spoken with Jake before and I never met anyone so focused, I believe he's made more tests and had more real world experience with this subject than anybody on the planet. His ultimate fix for the IMS is the IMS solution, I believe that is as good as it gets. The upgraded ball bearings are probably the second best fix but with his record of no failures ever from his shop over years of installations and none of his having anything other than splash lubrication its hard to see the benefits of DOF. He did tell me to have mine replaced after 75000 miles just to be safe. The IMS solution doesn't need to ever be replaced until the engine needs to be rebuilt.