Oil for my new RB26

[RyanGTR]

So, my last engine failed spectacularly. 625 KM's on the built motor and a thrust bearing went. I've owned this car for 2 years and 3500 KM's and I'm on my third engine, so I'm a bit scared of blowing it up

I'm trying to decide on what oil to run for my new engine.
-8000 RPM redline
-500 to 550 WHP
-Lots of track use (Drag, AutoX, and Road Racing)

RB26's tend to run (fairly) high oil pressures, a friend with a very similar setup to mine sees over 100 PSI of pressure @ 7000 RPM's with the oil at ~110C and 10W40 Royal Purple, if oil pressure levels make a difference in what oil you'd suggest.

I've heard lots of conflicting things about what to do with oil in a high performance car. Some people say the gains of synthetic are mainly seen when using extended OCI's. Others tell me that a good synthetic will perform better for a track day and perform better, and protect my engine from a catastrophic failure.

What would you recommend, for both break in and normal useage? I plan to follow the break in procedure recommended by my (new) machinists. 10 minutes of idling to break in the cams and flush any foreign bits out of the engine, then change the oil. Lots of varying RPM levels and engine braking to seat the rings for the first bit of driving, with oil changes again coming at 250, 500, and 1000 kilometers, and then falling into place with whatever regular OCI I see fit.

So, is it worth it to pony up with a synthetic? Cost isn't really an object if it means keeping my engine together. But on the other hand, if an expensive syn won't show a worthwhile advantage over a cheaper conventional/semi synthetic/whatever, I don't want to pour my money down the drain.

As far as my OCI, I was pretty much planning on just changing my oil after every track day, so every weekend or every other weekend. I doubt I'd put enough KM's on it between events to make it worth while to change the oil. I've heard of some people running Rotella-T in their engines, and this seems attractive due to the cost, but don't know if it would be a wise choice. I'm looking at anything from 5W30 to 15W40 for the viscoscity, but again I'm a little in the dark here.

Hope you guys can help me pick the right lifeblood for my engine so this one doesn't die in 600 KM's

-Ryan

 

[Jim 5]

Do you have the factory clutch? I'm wondering what could have wiped out the thrust bearing. Either there's inappropriate load on it or there was an engine assembly issue.

At 625km's a failed engine is not an oil issue. Wikipedia says this:

There is a common oiling problem with the pre-1992 R32 RB26 motors, as the surface where the crank meets the oil pump was machined too small, eventually leading to oil pump failure at high rpm. This was fixed for later versions of the RB26.

Have you addressed this?

If you have roller cam followers then cam break in is irrelevant. If you have flat lifters then you need to follow instructions.

Google the "motoman" engine break in. He makes a compelling case. I used it on 4 brand new engines including a built 302, a 3.2TL, an Odyssey and my BMW K1200S. One neighbor did it with his Jeep SRT8 and his Aprilia Tuono and the other did it on his BMW M3 and on his Corvette Z-06. Good results so far.

I agree with changing out the oil early. 15w-40 has great shear resistance, however with a power density like your engine a synthetic makes sense to address hot spots in the engine, including at the turbocharger.

GC (Castrol Syntec 0w-30) is an excellent oil. You can get it at any Canadian Tire, Partsource or Walmart. You might try that.

 

[Jim 5]

Also, I'm guessing your steering wheel is on the wrong side?

 

[RyanGTR]

Originally Posted By: Jim 5
Do you have the factory clutch? I'm wondering what could have wiped out the thrust bearing. Either there's inappropriate load on it or there was an engine assembly issue.


Clutch isn't stock, those like to keel over and die in short order. I'm running an OS Giken twin plate unsprung clutch with the OSG lightweight flywheel. I seriously doubt the clutch caused it, as I ran it on my stock motor for about 2500 KM's without any thrust issues. When I tore down the motor and looked at some of the things that were done to a very low standard, it leads me to believe that it simply wasn't assembled properly.

Originally Posted By: Jim 5
At 625km's a failed engine is not an oil issue. Wikipedia says this:

There is a common oiling problem with the pre-1992 R32 RB26 motors, as the surface where the crank meets the oil pump was machined too small, eventually leading to oil pump failure at high rpm. This was fixed for later versions of the RB26.

Have you addressed this?


Yes, that's actually one of the bits that I believe caused the failure in my first engine. The oil pump broke and you could see where it was wearing down and began to slip on the stock oil pump drive. Spun a few main and rod bearings and that's when I rebuilt it for the first time. I wasn't able to find a late R32 or R33/R34 crank with the wider drive, so I had a collar machined and fitted onto the crankshaft to increase the drive size from the stock ~12mm to the same 25mm as is found on the newer cranks.

Originally Posted By: Jim 5
If you have roller cam followers then cam break in is irrelevant. If you have flat lifters then you need to follow instructions.

Google the "motoman" engine break in. He makes a compelling case. I used it on 4 brand new engines including a built 302, a 3.2TL, an Odyssey and my BMW K1200S. One neighbor did it with his Jeep SRT8 and his Aprilia Tuono and the other did it on his BMW M3 and on his Corvette Z-06. Good results so far.

I agree with changing out the oil early. 15w-40 has great shear resistance, however with a power density like your engine a synthetic makes sense to address hot spots in the engine, including at the turbocharger.

GC (Castrol Syntec 0w-30) is an excellent oil. You can get it at any Canadian Tire, Partsource or Walmart. You might try that.


I hear a lot of GTR owners using a 10W50 weight oil, but my (limited) understanding tells me that the wider a spread in viscocity numbers means more additives means the oil will break down faster at high temperatures? I've read lots about the Syntec 0w30 being quite thick for a 30-weight, but will it be thick enough to withstand track days and 110-120C oil temps?

Thanks
Ryan

 

[RyanGTR]

Originally Posted By: Jim 5
Also, I'm guessing your steering wheel is on the wrong side?


I prefer to say it's on the right side

Here's a picture of some of my old engine carnage...

The second picture is the main girdle/main cap assembly, you can see how bad it overheated. It was completely out of spec and wasn't useable at all. The block was destroyed, the crank was way gone (Factory allowance on the thrust area is about 1.925", mine was over 2"!!) the oil pump was wrecked from FOD, the pistons were wrecked because bearing material was sprayed up along the bores through the oil squirters, and a rod was wrecked because some bearing material blocked the oil orifice and caused the bearing to spin, which overheated the rod and rendered it useless.

 

[Jim 5]

Thanks for the photos. That's some maximum carnage.

It really doesn't take that much space or special tools to rebuild an engine. If you want it done right and you're willing to spend the time, you should consider doing it yourself. The last two engines I built had to go back to the machine shop for several issues. First thing I did was spent a bunch of time measuring and remeasuring the machine work on the block as well as the specs on the bearing supplied. Then plastigauging everything that could be plastigauged. I found issues and it pays to take these steps.

I really think many machine shops and engine builders skip these steps because they feel they don't have the time. And it is time consuming. But if you're not doing it for a living, it's enjoyable.

You can farm out the machine work and then buy a few bucks worth of measuring tools to check their work. All you need is a factory manual.

I'm not sure what took out your thrust bearing, but there's so many variables in play here. I'd guess it was a combination of:

- oiling failure
- assembly error, maybe too much end-play on the crank.

A combination of the first two would be enough I'm guessing. A machine shop can resurface your crank and for many engines a oversized thrust bearing is available.

Just testing assumptions here and offering another alternative to consider. Oiling failure could have also caused the spun bearing and the bearing self destructing could have blocked the oil orifice after the damage was done.

The oil shearing in a large viscosity spread is caused not by additives but by the inability of viscosity improvers to stand up to a challenging engine environment. The narrower the spread, the less viscosity improvers and the more shear resistance.

Another way to lick this is through better base stocks. Synthetics stand out here. You may also look at something from redline or even amsoil. I don't know either product line well but they are both well respected.

That's an interesting cap assembly. If you have some time, post some more pictures. I enjoy this sort of thing.

 

[SLCraig]

Your car kicks [censored].

FYI my friend had the same issue with his RB20... I believe it was a 1990 or 1991. GTS-T I think.

 

[RyanGTR]

The old machine shop just did the machining, and then the shop I had work on the car did all the assembly. I don't really trust what they did after seeing the quality of work done on the other bits of the engine.

The new shop I'm using is taking all the small precautions. They've built engines for three of my friends, and seem like honest, reputable guys. My old pistons could've been used but they sat there and measured the pistons in front of me and showed me how they were a few thou off, told me they'd have to bore slightly smaller to compensate, and there could still be bearing material embedded in the pistons which could come back to haunt me at a later date.

I could do the shortblock myself, but I trust these guys, and the old shop is footing the bill so why not have it done by some professionals.

I'll post up some more pictures of the girdle setup later on for you, the RB26's are quite an interesting engine. The front diff is integrated into the oil pan, and the shaft which joins up to the passenger side driveshaft runs through the sump! Neat little setup to cut down on size, but if the front diff grenades it has a tendancy to take out the oil sump and likely your engine at the same time.

 

[RyanGTR]

Shot of the side of the block showing how compact it is. Deck height on an RB26 is 7.421". Compare that to some other "compact" motors like the Subaru EJ20 (7.913"), the Honda B16 (7.992"), or the 4G63 (9.015") and you get an idea of how small an engine it really is.

There's a shot of the sump showing the front diff and the shaft going towards the pass. side axle.

Two shots of how the girdle/main assembly sits in the block. I quite like RB's, they sound fantastic and are incredibly smooth motors. Just have some issues like the oiling problems.

 

[sprintman]

Redline 5W40.

 

[Scuderia]

Nissan uses Motul oils in their SuperGT racing program. They used it with the R34 (with a 500HP RB26), then with the 350Z, and now with the R35. You can get the 300V or this even more expensive stuff...

 

[RyanGTR]

I've heard good things about 300V, but it's about $18/litre.

GTR sump takes 4.5L, I overfill by a litre to prevent starving the oil pickup under hard cornering/acceleration, and my oil cooler/relocation kit added another litre of capacity.

I guess one of my questions is would there be an advantage to using an expensive oil and not changing it after track days vs. using a slightly cheaper oil and just changing it out after every track weekend.

 

[Jim 5]

Thanks for the extra photos.

Rotella 15w-40 changed after every track day might be an economical choice.

 

[Scuderia]

I know there are people who run the Motul for several track events and have gotten great wear results.

http://www.honda-tech.com/showthread.php?t=1307176

 

[RyanGTR]

I browse Honda-Tech and I'm suprised I haven't seen that.

I bought some GC because it was on sale at Wal Mart, I'm going to break in on Rotella because it's so cheap and I'll be doing 3-4 oil changes within 1000 KM, then see how the GC does. Do a UOA and if I don't like what I see I'll give the Motul a shot

 

[Jim 5]

I use metro tech systems in calgary for UOA's. They will PDF you your results usually within 24 hours of drop off. They are just east of Deerfoot mall in calgary if you live there.