RB26DETT spun bearings

[shoey]

Hello

I have just finished pulling down my GTR motor, after suffering what a few others have, and found that the 1st and 2nd big end bearings are shot. The damage was severe enough to have scored the crank beyond repair. This was caused by a track day at Wakefield were I only completed 5 laps before stopping. During this time the oil pressure and temperature was good.

My first question is: how does this occur? I assume from reading other posts that the motor experiences surging and also pools oil in the back of the head. This causes the bearings to temporarily be without oil and start to bind? Would the five laps have been enough to turn the bearings into paper thin strips? or had the bearings already had some damage?

the second question is: how do you stop this from occuring again? I have seen products like the Jun sump baffle kit, and the Grex sump extension kit with baffle. Also, I have read about blocking the oil from the head via head gaskets?

any help appreciated as I do not want to rebuild the engine only to have it go the next time I am on the track again.

Cheers.

[cereal]

Merli seems to know alot about the RB26 sump....

[knore]

Ide say it would have to have been somewhat damaged before the track day, and the 5 laps just finished it off.

Then again, i dont know much about RB26DETT internal details

[Sydneykid]

Hi Shoey, I would never ever take a GTR to the circuit with a standard sump and without an oil cooler. Oil surge is always very close. The more power you have or the better the suspension and tyres, the closer it is to oil starvation. It builds up in the head due to constant high rpm, the engine uses a bit, the oil gets over heated and it runs away from the oil pickup around the corners due to g forces.

We do the following;

*Add wings, one way doors and baffles to the sump

*Use an oil cooler with remote filter

*Increase the diameter of the oil return galleries in the head and block

*Fit an external oil return direct into the sump from the rear of the cylinder head

*Use hi viscosity oil (Castrol Formual R Synthetic 10W60 in our case)

Our race team fabricator makes ours as I am not happy with the "off the shelf" products. Performance Metalcraft do a really good custom sump for GTR's. :aroused: That would be my choice for "retail" product, there are probably others around.

As for you questions about 5 laps being enough, I have seen a GTR chuck a rod out of the side of the block in 3 laps. You were lucky.

Hope that helps :wavey:

[knore]

Ive noticed alot lately when being around GTRs that they have a problem with high oil temps, why is this sk?

Why doesnt RB25DET have the same problem? Minus the extra turbo ofcourse

[Sydneykid]

Ive noticed alot lately when being around GTRs that they have a problem with high oil temps, why is this sk? Why doesnt RB25DET have the same problem? Minus the extra turbo ofcourse

Let's see, I could start with RB25DET's have one ball bearing, watercooled turbo and a GTR has two plain bearing, oil cooled turbos. Then I would follow it with GTR's have a hot diff bolted to the side of the sump and a drive shaft running through it. I would finish up with GTR's make more power (standard) so they have to produce more heat.

I am sure other could add to the list.

[hungry6]

yes rb25 does have the same problem, but it doesn't get exacerbate by the existent of a 4wd system as is on the gtr. a gtst would swap ends, if u pushed it hard enuff, it only becomes a problem when you run semi slick,

[fatz]

i find your standard gtr sump will give the engine a great long lasting life if you dont rev it past 7 on the track

if your going to rev it harder run the baffles and the extra capacity and anything else

pete

[GunMetalR33]

Hi guys, I dont mean to steal the thread but I would like to know if this effects me?

I have a r33 gts-t running about 200rwkw, when should i start to think about oil heating issues?

[PRIMO]

i have heard the genuine nissan clearances are to tight from factory .7thou on the rods and .9 thou mains i think is factory clearances, i was build a toght motor when my tuner pointed out he think the clearances are to tight for big HP standard is ok but for big HP he recommended 1.2 for the rods and 1.5 for the mains , he said make sure its blue printed and machined correctly by reputable machine shop, he said this in turn will creat more of an oil surface film and decrease the chances of metal to metal if used with full synthetic oil.

please correct me if anybody has been told differant this is just 1 person view point not fact

has anybody heard this also ?

[Duncan]

Hi Shoey, I would never ever take a GTR to the circuit with a standard sump and without an oil cooler.  Oil surge is always very close.  

Now in hindsight that seems like great advice

The new engine will have Trust Sump extension and baffles, big oil cooler and restrictor in the oil gallery.

[Ustasa]

What I can’t understand is how the car was built with so much techno detail ie. attessa, twin afm’s, hex throttle bodies and yet on the track with a few laps a lot of them die a miserable death.

Surely the car was flogged senseless around a track before sold to the public? We aren’t talking about a chook cooker a to b grocery getter here.

Strange….

[shoey]

Yes, I did not think that a car like the GTR would suffer too much from track days. I did actually fit a remote oil filler and changed oil before going. Thanks for the advice. I think I will look into the custom sump idea as I would like ot return to the track without having the large repair bill.

[Dror]

Do your self a favour and don`t go out on the track untill you have sump baffles, extra capacity etc. My GTR shot a rod out the side of the block in only two laps of a short circuit. It already had an oil cooler and remote filter but on semi slick tyres it took no time at all to cause a very expensive failure. It`s not worth the risk.

Cheers, Dror

[R31Nismoid]

What I can’t understand is how the car was built with so much techno detail ie. attessa, twin afm’s, hex throttle bodies and yet on the track with a few laps a lot of them die a miserable death.

Surely the car was flogged senseless around a track before sold to the public?

would it be fair to say that most examples of GTR's on the track are modified to a certain extent?

running more boost/exhaust and sometimes ECU to be a making a lot more power...

hence pushing the engineering a bit. Not that GTR's are not over engineered but remember the full track variants would have all the above mentiond 'additional mods' like baffling etc etc

As SK said, suspension and/or tyres makes a big difference to the whole equation too. Even on a stock car i would imagine

[shoey]

My car was running an exhaust, had the boost restrictor removed and had adjustable cams gears. I think it produced 211kw at 4 wheels at Croydons. Therefore a very mildly modified example. My suspension was konis with King springs but I was getting a lot of slide due to cheap Khumo tyres. I think the excessive slide would also have contributed to oil movement.

[ferni]

How much would it cost for a baffle sump + install (in an R33GTR) ?

Does the engine have to come out?

[shoey]

SydneyKid, I have one more question: You talk about enlarging the oil chambers returning to the sump. Do you also recommend putting in a oil restrictor for the feeds to the head? Or is this not necessary because of the larger returns and extra external return oil feed?

[Sydneykid]

SydneyKid, I have one more question: You talk about enlarging the oil chambers returning to the sump.  Do you also recommend putting in a oil restrictor for the feeds to the head?  Or is this not necessary because of the larger returns and extra external return oil feed?

RB26DETT's have an oil restrictor in the top of the block standard. Make sure if it is removed for decking, that it is replaced.

[knore]

How much would it cost for a baffle sump + install (in an R33GTR) ?

Does the engine have to come out?

You can get Trust sumps and oil cooler, RB26DETT on here has them on his GTR that is for sale

Dont know how much they are, but SK said local/custom ones seem to be better than jap brands