My rod bearings after a HPDE

[aquariuscsm]

The 1990 Z32 has it listed as 4 5/8 quarts,then the later years has it as 3.5 or something like that. I always wondered if the 3.5 was the *minimum* to reach the acceptable capacity,and then the 4 5/8 was the completely to-the-top full capacity? If I just put in 4,it`s only halfway up the dipstick on my car. 4.5 puts it right at the top. Heck,I may just put in an even 5 next time like Z-Doc suggested.

 

[VG30DETT]

This shows what you need to know:
Link

So I would say 4.5quarts plus a bit to account for the oil filter is optimum.

 

[EricJRoy]

My first post

I had a 1991 and 1993 240sx and I know the the Owners manual said to use 5w-30 or you could use 10w-40 if ambient was above something like 32*F. So I was very suprised to see the post from aquari... showing the 300zx FSM calling to use 20w-50 in hot climates and turbo cars. YOU SHOULD BE FOLLOWING THE FSM!!!

I live in Buffalo, NY so I have to deal with the same climate as you. I now have a 92 BMW 325i that I track and only drive spring thru fall and therefore use Castrol syntec 5w-50. I think you should absolutely be using a 10w-40 or up to 15w-50 especially at the track and since your car is turbo, enough of the lightweight oil already
edit: The z32 engine bay is so tight it must get so hot, along with and oil cooler, hood vents might help cooling

 

[EricJRoy]

Originally Posted By: L_Sludger
Originally Posted By: Boss302fan
Mobil 1 15w50 would work great in this application... I am not a big Mobil fan but the 15W50 is truly a great oil.
I ruined a motor at the track - rod knock - with that Mobil 1 15w50 oil.


What car and what motor, and what does the Owners manual call for?

I think you do have to be careful which engine you put the heavier oils in. I know my brothers 2004 Silverado 6.0L Owners Manual calls for 5w-30 only and specifically says 'Do not use an oil like 20w-50'

 

[VG30DETT]

It doesn't call to use anything per se..it just shows what you CAN use depending on temperature. And as I said before, this is more than likely accounting for regular dino oil that shears out of grade sooner than premium synthetics.

The 300ZX TT does have an oil cooler standard. The tight engine bay does not necessarily mean the engine coolant/oil temps run any higher than other cars, because after all it is the heat exchanger's job in the front of the car to do the job of cooling it down e.g. air passing through the radiator, not the engine it self. So as long as the HE does its job and gets enough air, then this is not an issue.

Sure if the oil runs at extremely high temps, then a higher viscosity oil should be used to maintain enough film...but a sort of counter intuitive way of thinking about it is also that a thinner oil takes away heat faster and reduces temperatures as well, not to mention flows better...

So again, we would need some temp data to know for sure. Based on the pictures, do you believe this is an issue of viscosity?

 

[EricJRoy]

I do believe it is an issue of viscosity since the vg30 must have tolerances designed to use a thicker visc oil: max 20w-50. The 240sx's KA24de engine was designed to use thinner oil, max 10-40

Oil temp might go way up under load too, I guess you need data so start monitoring

 

[demarpaint]

Could those bearings in question have been installed a little too tight and out of spec? That would make it a little harder for oil to flow through and do its job.

 

[VG30DETT]

These were the factory installed bearings that were never touched.
I believe bearing oil clearances are about the same between the KA and VG if you look at the FSM for them. Eric, would you agree that the heat would be the greatest in the back of the block next to cyl#6? Again, I think it is accepted that at least all bearings would show damage if it was a viscosity issue...and in this case it was at the front of the block where damage occured.

 

[jwagner162]

how many miles on the motor? miss any shifts while driving. could have been over reved. the few motors ive seen with spun bearings are usually the bearings farthest from the pump. (like this one?) as they see the lowest pressure. i run a 3sge 4cyl toyota motor, and they are very suseptable to spun bearings when the oil is low and run hard, as the sump will suck air. mine holds 4.3qts. id seriously look into something that holds 2 more quarts with good baffles, and get a pressure gauge. maybe look into an oil cooler if there isnt one fitted stock. dont feel too bad the first time i spun a set i didnt know what was happening and kept running, bad plan, i welded all the bearings to the crank! good luck. note:i personally would run a thicker oil due to higher temps.

 

[jwagner162]

does it seem odd that the lower bearing has a hole in it?

 

[VG30DETT]

Well it uses the same part for top and bottom halfs..the spun bearing has metal smeared over the hole.

 

[aquariuscsm]

If you want a lighter oil,I wonder how well the Valvoline VR1 10W30 would work?

 

[jwagner162]

im still new here but i would highly advise against going lighter. running that hard creates way more heat in the engine. especially if you only have 4 quarts of oil to cool the internals with. id go 20-50 synth. my track car turns that to water in less than a hundred miles at the track. so you have to change it very frequently due to the loss of viscosity. my rule of thumb is when its black or thin(watery) change it.

 

[aquariuscsm]

Hey jwagner,you`re definitely more experienced with racing/tracking that I am. If you like to drive fast and hard (but don`t race),do you think a thicker oil (10W40-20W50) is the way to go? My Z32 is an n/a (non-turbo with 63,000 miles) but these engines definitely generate some heat. What would be your pick of the litter for spirited daily driving:

Valvoline white bottle 10W40,20W50
Valvoline VR1 10W30,20W50
Pennzoil yellow bottle 10W40,20W50
Pennzoil GT Racing 25W50
Mobil 1 15W50
Royal Purple 15W40,20W50

Oddly enough,my car runs the best on dino oils. I haven`t really been impressed with synthetics. My car`s "sweet spot" seemed to be the Valvoline white bottle 10W40.

 

[hustler]

Originally Posted By: addyguy
Racing something THAT hard, go thick all the way - straight 40-weight racing oil, or HDEO, wouldn't be out of place here.


What is the benefit of using a straight-weight oil again?

 

[hustler]

Originally Posted By: hooligan24
I have used GC in my Neon SRT4 during an HDPE with oil temps reaching 280-290*f. I then continued using the oil for a couple more thousand miles. UOA came back normal except for high lead, which Blackstone said it was most likely from the leaded race fuel I ran during the HPDE, because all other wear metals were normal. I can post the UOA if you like, but it is a different engine. I am just trying to make the point that I used it in a turbocharged motor and also saw 280-285 degree temps.

I dont think the oil itself failed...


I've been tracking a 250-330whp Miata for about 21-hours now and I have awesome wear numbers in my analysis (search my user-name) with a 5-40 oil shearing down to 5w30 with about 3-hours on each oil change due to 11.3-11.5:1 AFRs. I also experience 240-280*f oil temps and I'm still working on the oil cooler ducting which needs direct air.

Install an accusump and call it done. They work well enough for million dollar cars running at leMans, and they work in our budget racers.

 

[jwagner162]

IMO royal purple would be the way to go for about anything based on looking at the VOA's. however it is expensive. i would use it if i didnt have to change my oil every 2 races due to viscosity loss(id be like 35 bucks a race just in oil). i found my balance of price/quality with valvoline synthpower 20-50. very comparable synth and about $7 a qt. if youve found the "sweet spot" stick with that. for a DD the recomended weight would seem best. even though your in for some spirited driving. itll be nothing like true track time. i take my car out start it once and then run it between 6000-7500rpm for a solid hour. just screaming up an on-ramp or racing someone of a light wont generate temps near what ill see. put it this way 5gals of gas lasts me about 20min.(and thats in an 87 n/a econo-sport.) new dino oils are very comparable to synth. if you notice your oil is thin around 3k then you may consider going up a weight. also IIRC the vr-1 and other racing oils have almost no detergents in them so id avoid thoose in something you want to put some miles on.

 

[jwagner162]

if money is np then id go RP with a mobil1 or p1 filter. the main thing with a track car is residual heat. your car never has time to cool. the water pump is running so fast the coolant doesnt have enough time to cool in the radiator. same with the oil pump. some people actually remove some of the fins on the water pump to slow coolant flow.

 

[aquariuscsm]

I`ve got one of the "good" rebate coupons for VR1 Valvoline (Free case of Valvoline VR1 via mail in rebate,not the BOGO one). I wonder if I should get the 10W30 or the 20W50? Would the 10W30 be good enough for spirited driving,or would the 20W50 be a better option? If it came in 10W40 that`s what I`d buy.

 

[VG30DETT]

Aquariuscsm, the 300ZX non-turbo is not equipped with an oil cooler like the TT is. If I were tracking an NA I would look to installing an oil cooler to keep the temps reasonable...again just get an oil temp gauge to stop guessing. But again, just because you may feel a lot of heat when you open the hood, it does not mean the oil temps or coolant temps are running hotter than other cars with less crowded engine bays. But still, if I were to run a dino oil I would run with 10w40 in an effort to account for it shearing down during use.

Everyone has their own opinions on oil to use, but in regards to VR1, after seeing all this recent stuff I don't see it being any better than any other dino oil off the shelf like YB.

Jwagner162, after the event when I drained the oil and changed the bearings, the oil looked fine.. not like water. Besides the oil didn't have much miles on it. I don't think this engine is hard on oil in terms of shearing. What engine do you have in your race car if you don't mind me asking?

I agree with what is said here about the correlation between viscosity and heat, and the fact of oil shearing faster under racing conditions at high RPM (I would use Redline oil or similar) which is all really just common sense around here.
But I also think it is too easy to jump on blaming viscosity..
IMO, known oil starvation issues + 2 adjacent rod bearings damaged while others fine in hotter areas = caused by oil starvation.