My rod bearings after a HPDE

[jwagner162]

-i was wondering if a tt would have an oil cooler. and i think im with VG on the 10-40.

--I run a gen 1 3sge. 4cyl. toyota. am looking at doing an oil cooler aswell though my temps are ok (cant be to safe). same type thing where the 3sgte(turbo) has an oil cooler. and is a pretty quick fit.

--agree w/ starvation but remember as viscosity goes down so does oil pressure.

---i may have missed, but are the bearings you spun closest to the O.P. or furthest away?

 

[VG30DETT]

The bearing that spun was the cyl#1 right next to the oil pump, and cyl#2 bearing did not spin but got damaged...the theory is that a pocket of air displaced oil to those cyls first.
Although pressure through the oil galley's go down as the oil heats up/thins out, you have to remember that the oil flow is also going up.

 

[aquariuscsm]

Here`s some bearings from a VG30DETT motor with only 40k miles w/M1 10W30. Another reason I`d never use that stuff. Look at bearings #3 and 4. Should they be that scuffed?

 

[VG30DETT]

That is a bit out of context...you don't mention his power levels, amount of abuse, and the fact that it is a rebuild. Still, the guy wasn't blaming the viscosity. Cyl #3 shows obvious signs of particle wear.

 

[aquariuscsm]

He`s running 426hp/420wtq. Daily driver.

 

[CBR.worm]

Other things to keep in mind.

They could have been too tight from the factory.

Is this failure typical of these motors? i know some motors always take out specific bearings due to oil system design flaws where some bearings are always under-oiled, but don't fail until power is turned up.

How is the crank? Main bearing tolerances ok? Oil galleys clear?

Plugs in those two cylinders look like all the others?

 

[Gene K]

I dont know anything about these engines in racing use but I will give you a bit of advice anyway.

Figure out what you want the sump viscosity to be (ie 6.0 cSt) and then figure out what oil temp you are going to run. Now chose an oil that gives you that. That might be anywhere from SAE 20 to SAE 70.

An oil thats the correct viscosity at 212F Sump Temp being used at 302F Sump Temp is not a good idea. You have to take into consideration the 75% loss of viscosity

 

[aquariuscsm]

I`d go for a racing 50 weight dino oil. BuickGN said on all the raced engines he`s torn down,that the ones using dino always had the least wear. I`d use one of these. You can get these usually for around $3 and some change a quart. I ordered a case of the Pennzoil GT from O`Reilly and it was around $3 a quart:

Pennzoil GT 25W50,50,or 60
Valvoline VR1 20W50,50,or 60

Mono grades for track only use maybe? Multi grade would seem to me to be more of a daily driver oil in a hard driven performance or turbo car. Jmo though since I don`t race. I love how the Pennzoil GT totally bathes the cam in a thick layer of oil. Oil film is also still completely covering the cam after a few days of not starting the engine too. Startups are silent with this oil.

 

[zoomzoom]

looks like oil starvation issue to me. if you want to run lower viscosity oil but with high HTHS then redline is the obvious choice..their 10w-40 will give you protection of 50wt oil

 

[Lethal1ty17]

its an oil related failure not because the oil brand sucked, but because the oil simply wasnt there in a large enough quantity.

the G-loads lowered the amount of oil that reached those front bearings obviously, that in and of iself will murder a stock cars bearings, now double the power and you have a recipe for disaster.

i would definately run at least a 40wt oil due to the fact that turbos are a gauntlet on oil, and you have 2 of them to break down the oil and heat it up to where its quite thin. i would suggest and oil cooler if you dont have one and maybe even step it up to a 50wt depending on the temperatures your oil is reaching.

 

[aquariuscsm]

Oil brand definitely didn`t suck,it was just too thin. Search on twinturbo.net and you`ll see everytime a bearing was spun,it was with a 30 wt oil during tracking or racing. The really knowledgable Z32 people only race or track with a 50 wt. Alot of the racers use Mobil 1 15W50,Amsoil 20W50,RP 20W50,and Pennzoil dino 20W50 and never report any engine failure.

 

[GregGood]

In addition to increasing the sump capacity, there are a few other things to address.

I don't know anything about this particular engine, never having built one, but there are many similarities with other engines, regarding to bearing clearance, etc.

I see in my Mahle bearing catalog that the rod journal diameter is 1.967". Depending on the oil you run, the vertical clearance should be .002" for the lighter weight oils and up to .0025" for a heavier oil.

Side clearance on the rods is important. Many factory engines come too tight, and that restricts oil fow across the bearings. The minimum I would run would be ~.015" side clearance. It's common to see engines with as little as .006". Not enough for racing.

Another item is the oil passages in the crankshaft. Is the crankshaft cross drilled? If so, then you need to block the cross drilled passages and turn the crank into *Chevy oiling*.

And lastly, how well does the oil drain back to the pan from the top end of the engine? If it does not drain back well sometimes we add -12 lines at the back of the heads and run them directly to the sump.

Just some food for thought. Good luck with the next engine.

Greg

 

[VG30DETT]

Thanks for the input Greg!
I have heard some talk of oil drainback not being too fantastic on this motor and so what you say completely makes sense.
I will ask an engine builder who builds mostly only these engines regarding the crank passages and bearing clearances.

I am still on the same engine with replaced bearings after almost 3k miles. I may be attending another PDX event at the same track soon, with an oil temp gauge this time It would be an interesting experiment!

 

[Faststang]

Oil starvation.... If the pickup can't find any oil what are the next 2 cylinders that won't recieve it's oil? My reasoning is they spun first when the pump sucked up some air.

Also, don't know if you saw it but a friend in the auto industry says avoid mixing oils at all costs. Some oil additives in one oil can react badly with others.

 

[Steve S]

Originally Posted By: Faststang
Oil starvation.... If the pickup can't find any oil what are the next 2 cylinders that won't recieve it's oil? My reasoning is they spun first when the pump sucked up some air.

Also, don't know if you saw it but a friend in the auto industry says avoid mixing oils at all costs. Some oil additives in one oil can react badly with others.
They use all the same additives. Look at the uoas.

 

[unDummy]

Once you mod an engine, OE recommendations shouldn't even be considered. Toss the owners manual and factory service manual out the window. Consider 1k-3k OCI's with thorough UOAs.

Pick an oil that can tolerate the temperatures you run with, like a full synthetic always.

Use viscosity to make up for temperature IF you can't control temperature. In the good ol' days, Redline use to have complete viscosity curves for their oils on a graph, to help with weight selection. I'd use a 50wt and go up or down as needed.

Amsoil, Redline, Mobil1, RoyalPurple, Neo, Torco...... are some to consider. Another option are the Euro 10w60 oils.

I hate that all Nissans have undersized sumps. If there is any room, add a remote filter with dual filters. A couple FL299 filters will double the sump size pretty inexpensively.

Also, older Nissan oil filters don't have bypasses. I've seen failures where the bypass didn't bypass enough. If you don't go with remote filters, time to use a non-Nissan PN on your engine. Having the backup of a filter's bypass when your engines bypass isn't flowing enough, can save your engine.

Don't worry about overfilling. Once an engine is running, the pan level drops. So, give it the extra pint or quart, and research crankshaft scrapers if you don't have one already.

Accusump or any oil accumulator is a must on just about any track car.

 

[hustler]

Originally Posted By: unDummy
I hate that all Nissans have undersized sumps. If there is any room, add a remote filter with dual filters. A couple FL299 filters will double the sump size pretty inexpensively.


I like a big oil filter too, but if there is no oil in the pick-up tube there is no pressure from the positive displacement pump. Maybe its time for trap-door baffling.

 

[unDummy]

Status of engine?

 

[VG30DETT]

Well went to a PDX at Monticello Motor Club again in September...using same engine with the replaced rod bearings...got rod knock this time at the end of the 3rd session. Changed out the oil the day before with no particles in the oil. Used 4quarts Redline 10W40 this time. I couldn't install the oil temp sensor in time due to not having the adapter for the BSPT..but I'm sure it was not an oil temp issue..
Havn't had time to inspect yet. Wish I ran the extra quart..maybe would've given me some more track time.
I'll definitely post when I get a chance to look into it.

 

[Nick R]

Ouch! For this, I think if I was doing something similar I'd use Redline 15W-50