Trouble choosing oil: spec 60-70psi by 3,000 RPMs

[OVERKILL]

Originally Posted By: Daigle

OVERKILL maybe im perceiving a problem thats not there... but with 15wX (40 rotella dino) my motor was SUPER loud at cold start and idle in general, (10w30 was noticably quieter) and the pressures were so high i had to chang my driving behavior durring warm up driving. i also thought 90% of engine wear happens at startup and a thinner cold rated oil will help reduce that. are these concerns somewhat neglegable? of course i want my motor to run well and last as long as possible. good to know MITCH! i was hoping it wasnt to big of a range for one oil.

But were the pressures acceptable (according to the values listed in the FSM) once the oil was warmed up? I'm under the impression that they were not, correct? Another oil would be Mobil 1 Racing 0w-50 if you can get it. Would give you an oil that is thinner at startup than the Rotella, but still heavier at operating temperature.

 

[dailydriver]

So, how much boost are you pushing through that DET, and what size turbo?? (Or is it the stocker with a hairdryer slapped on, and NOT an RB20 transplant/swap??)

 

[Daigle]

unfortunately im not too sure what the pressure were at 3,000rpms (just at idle and WOT listed in 1st post). this was last year before i put too much thought into my oil choices. about to do an OC so im going to see what of the reccomendations i can find OTC (walmart/AZ/Advanced). i'll post up the new values, maybe it will help someone else searching down the road. its just a 2.4L DOHC 4 banger and i added the T, same 4cyl motor they put in frontiers. I'm running 18psi on a holset turbo off a 5.9L cummins 56mm comp inducer/65mm turb inducer. its a "54 trim" comp. 18psi by 3400 RPMs and holds it to 7500. forged pistons and rods, titanium valve springs, light ported head etc. ive done some stock block ones too. all tuning done by me.

 

[Daigle]

if im trying to hit 70psi at 3k, and lets just assume my popoff is 85-90psi, wouldnt that lead you to believe im going to hit bypass not far after 3k? id think by 4500 I'd already be there. i dont know what the actual bypass pressure is though, i have the 3" thick FSM but it doesnt seem to call it out. is there any other place i might find this info? im about to try some of that 15w50 mobil 1 you reccomended and i guess im just thinking alloud here.

 

[Daigle]

back with some results. ive come to the conclusion my oil pressure at 3k may be low due to bearing clearences. they are .0015", stock is only about a half thou less but maybe thats the 5-15psi im looking for? i may end up shimming the pump. if i was to shim the pump pressure id have to increase the pop off pressure too? havent looked into shimming a ton yet so still a little unclear on the details. so i ran 15w50. unfortunately new england weather is crazy this time of year. it ended up being like 45-50F that day so it wasnt ideal. the motor had 80 psi cold idle, about 20 higher than thinner oils. motor was loud and even once warm it still sounded louder than usual at idle and light cruise. the motors always had a fair bit of piston slap (darn arias pistons choice of aluminum!)when no cylinder pressure so its a clear indicator of noise when changing oils. once warm my pressure at 3k was still below spec. i got about 56 at 3k spec again is "60-70psi" its probably a great oil for me on the track but warming up and with street oil temps, its not seeming ideal. im going to put this oil on the back burner till ambient temps hit 80+ and try it again. i also put 0w40 in it but didnt get to drive it. i was installing cams and they said rev at 3k for 20 min then change oil. cam break in!?!?!?! i had never hear of that, but figured id follow mfg instruction. CLIF NOTES 15w50... pressures still too low at 3k and car sounds a little ruf at street temps. will try this oil again when its 80-90F in the summer, its still only in the 50s. tried 0w40 but didnt get to drive on it, semed like a good oil for me on the street and im hoping with the new oil cooler going in it will work for me on track too. last. if anyone has knowledge on shimming oil pumps im all ears!! i know roughly the size shim needed but want to fully inderstand the implications of what im doing first.

 

[sunruh]

Originally Posted By: Daigle

i was installing cams and they said rev at 3k for 20 min then change oil. cam break in!?!?!?! i had never hear of that, but figured id follow mfg instruction.

this is old old man. heck i remember that was the suggestion from crane back in '81 and that info wasnt new then!

 

[aquariuscsm]

How about Syntec 5W50?

 

[A_Harman]

Originally Posted By: sunruh

Originally Posted By: Daigle

i was installing cams and they said rev at 3k for 20 min then change oil. cam break in!?!?!?! i had never hear of that, but figured id follow mfg instruction.

this is old old man. heck i remember that was the suggestion from crane back in '81 and that info wasnt new then!

Well, yeah. An oldie, but a goodie. Mathematics hasn't changed in the last 30 years. Valvetrain loads are actually less at 3000 rpm than they are at idle, so there is less contact stress as the cam goes through peak lift. And the higher operating speed means more oil spraying around and better lubrication due to enhanced hydrodynamics.

 

[Daigle]

Originally Posted By: aquariuscsm

How about Syntec 5W50?

hadnt noticed that option, i'll try it... i like the 0w40 in there. only thing thats weird is my oil pressure gauge flutters. its a stepper motor so it can jump between ticks sometime, but it does it all the time now. just an observation. random question hoping one of you knowledgable fellows could pin point. on the topic of piston slap... obviously when first started the motor sounds rough for a few seconds till the oil gets flowing. after that for about 15-30s the motor sounds great, the slap is almost gone, then bam right back to slapping. im just curious why/what quiets it for a short time. it happens quick, its not like its related to temperatures. its slappy theres nothing simple i can do about that, just my brain being curious.