POSSIBLE CURE FOR OIL ISSUES

[signalpuke]

I am trying to find as much information as possible on my RB20DET. I have read on skylinesaustralia that the RB motors have an oil issue, and the main mod people are using is a restrictiction of the oil feed to the head of the engine. If that is the correct way to go about it, why didnt Nissan implement this change from the factory? I was wondering if anyone has had their crankshaft, connecting rods, and the underside of their pistons coated (teflon)? This would not only help shed the oil from these parts and send it back to the pan faster, but it would also increase HP at higher RPM due to less parrasitic drag from heavy oil 'sticking' to these parts. The process is cheap too.Do you think this would cure the oil issue in the RB motors?

[zdonner]

I'm not very familiar with this topic but I did notice something I would like to point out. You say that it would add/free-up HP by lessening drag, however; is that to imply that the Teflon coating would not have the same or similar drag as the oil alone?

[signalpuke]

No, oil sticks to metal, thus making the metal part heavier. I wasnt talking about gains from drag coeffecient reduction on the rotating parts (like polishing them) so that they can go up and down faster, I am talking about lessening the rotational mass of the bottom end at high RPM. There are gains to be made by coating the sides and top of the pistons with other materials as well, but that is another discussion.Teflon is smooth, and oil slips right off it. V8 guys have been doing this for years, even on a stock motor gains are made, but that isnt the point, just another benefit.

The point is that the oil in the motor will reach the pan faster.

[Carl H]

oil has to stick to the bearings for the hydrofilm that the rods and crank ride on to be generated...if teflon simply allows the oil to slide off whats the point of having oil if there is no film for the bearing to ride on?reason nissan didnt fit smaller restrictors to the motor from factory is because they never intended for the general public to be revving these motors to nearly 9k and making 400+whp.

[signalpuke]

http://www.k20a.org/forum/show...26092That is what I am talking aboutCarl, bearings will not be coated, nor the surfaces on the crank or rods that contact the bearings. Same goes for the wrist pin on piston.

[Carl H]

gotya, misunderstood.seems like it would work in principal, are there massive gains to be had doing this tho to warrant the extra cost?

[signalpuke]

Compared to the prices of some other stuff people do to their motors to make it less reliable, I have no problem spending south of $300 to make mine more reliable.I havent priced out one of those Tomei oil things one of the SAU guys was talking about yet, but buying anything from Japan costs an arm and a leg (I really dont care for the JDM crap anyways) and I dont want to sacrifice oil to the head of the motor either. I browsed here and on SAU and saw no one had done this and thought I would ask. I have the RB20 simply by chance, I hate the fact that was made only in a country on the other side of the earth 15 years ago. If the motor blows I will replace it with an engine that is offered in the states. Until that time I want it to last as long as possible. I have been contemplating having the journals machined out to accept RB25 rods and getting some light weight high compression pistons with an offset wrist pin and just reving the hell out of the damn thing. ITB's....j/k

[Carl H]

the restrictors are only 6$ per...need atleast 2x on hydrolifters imho.

[signalpuke]

No negative side effects on the head? If that is the case I will do the restrictions. This is in the oil ports in the block correct? I really dont want to blow the damn thing up as it is supposed to be my daily driver, the honda is my fun car

[krayton]

are u taking your engine apart just for these mods?

if you were, id just run it like it comes. for a DD you shouldnt really have these problems. all these oil problems are people with high hp/track cars.

id just check your oil pump to make sure wear and tear is ok, then run it. a DD isnt hard on the engine

[Carl H]

no the head will be fine with dual restrictors...

[Darius]

search as this topic has been covered in a lengthy thread about three months ago. I'm too lazy to search for it for you.

[zdonner]

No, oil sticks to metal, thus making the metal part heavier. I wasnt talking about gains from drag coeffecient reduction on the rotating parts (like polishing them) so that they can go up and down faster, I am talking about lessening the rotational mass of the bottom end at high RPM. There are gains to be made by coating the sides and top of the pistons with other materials as well, but that is another discussion.Teflon is smooth, and oil slips right off it. V8 guys have been doing this for years, even on a stock motor gains are made, but that isnt the point, just another benefit.

The point is that the oil in the motor will reach the pan faster.

No what I am saying is not that the oil will stick to it or not, it's that he coating with add wieght just like the oil does.. Teflon does not defy physics.

[ISUJinX]

To the OP ...

Yes, the teflon coatings will help shed oil, but the problems with the RBs is too much oil being in the head, and thus not enough in the pan. Restrictors keep more in the pan. So, Teflon coating the undersides of pistons and the beam part of the rod will help slightly with free revving, but wont have any noticeable impact on how high you can rev it. The oil simply isn't enough weight. Nor will it do any more to help keep oil out of the head.

Most of the V8 guys using coatings are running N/A. On turbo cars, the oil is often used to cool the crown of the piston to minimize detonation when on boost. This is the same reason people coat the tops of pistons for use with nitrous - increased heat resistance.

You're better off installing the $6 restrictors than having things coated.

[jdmser]

Where can you get the restrictors from and how do you install them? If all you have to do is pull the head and use a drift to tap the old ones down and then tap the new ones in on top of those it's deffinitely worth doing.

[StricNyne]

the tomei oil orifice r u refering 2 ?

[Darius]

Seriously, guys that are new to this idea need to read this thread because obviously nobody searched for "oil orifice". zerothread?id=189416

Before everyone gets carried away with this modification, please remember everything else that is associated with it. If you are planning on having a high hp (550+hp), extended high revving motor, have already done or are planning to do the JUN crank collar modification (required to pull the crank), and know that once you pull the head that you will most likely have to machine the head and block to install a metal head gasket to give you insurance when pushing for 550+ hp, you are most likely in for a complete rebuild.

THIS IS NOT A "WEEKEND TO PULL THE HEAD" MODIFICATION. So don't think, "WOAH! Only $6 to improve the reliability of my RB!" If you are planning on fully rebuilding, then do it. Otherwise let sleeping dogs lie unless you happen to have a boat load of money laying around to do a rebuild unexpectedly.

If you find yourself getting excited about this modification, don't. Go back and realistically reevaluate your power goals and then decide. If you still think you need this modification, proceed to a japanese parts website like nengun or greenline.

[signalpuke]

Cool, that is the kind of response I am talking about. Trying to decipher what the Aussies were talking about was a pain in the ***. I am no way looking for 550+ whp, this is a daily driver. I want the thing to be reliable for daily driving because it has comfy seats and AC/PS. 300-325whp is prolly the highest I would want to go, so I will just do some of the other oil fixes and call it a dayThanks-Aaron