Just curious what some of the higher hp/boost guys are running on built motors? What's your main and rod bearing clearances, what weight oil do you run, what oil pump, what your cold start oil psi, and what's your hot oil psi after driving for 30min?

My bearings are at .0025 on mains and .0028 on rods. Using a melling 10296, and I'm running 5w40 Mobil delco 1 esp synthetic diesel oil. It's one of the newer diesel oils, I spoke with the guys over at mobil1 oil and they told me this oil is specified for newer diesel trucks and for gasoline trucks. Comes in 4qt jugs and runs about $24 per gallon. Anyways on cold startup it's around 60psi then after its warm about 35-40psi with no driving. After driving for a while in the 90-100 degree heat the oil pressure settles to around 22-25psi. Never gets bellow 22-25psi sitting still, hot, idling at about 700rpm. The pressure goes up as soon as I give it any throttle and stays around 50-60psi on WOT. I know my clearances are on the bigger side, and I'm not too worried about the oil pressure, just seems like a big drop from cold to hot oil psi....

 

I don't know if I am higher hp or not. But I am having pretty low oil pressure when hot. For the first 1000 miles or so I was idling around 35-40 when hot. Now it is about 26-28 when hot at about 3k miles on the motor. Last oil change there was quite a bit of metal in the filter. I have 300 miles on this oil and I am going to cut open the filter this weekend. I think I have a bearing coming apart.

 

And I have been running 10w30.

 

Those are some tighter clearances... Wonder why the builder went tighter on the rod bearings compared to the mains? Not a bad thing, but if you're in cold weather most the time, I'd run some 5w30... What oil pump you running? What cold start oil psi are you getting? Any weird noises or anything? And does your pressure still rise with the rpm's?

 

No relevance but I'm running a unknown mile stock shortblock, (Turboed) with a melling high volume pump. Tried every type of oil under the sun trying to cure similar oil pressures as you guys at operating temp. Switched to VR1 20w50. I run no oil cooler and it holds 40 psi at hot idle. It doesn't break down like the other oils, supposedly has a much higher zinc content. Been pretty happy with it!

 

I don't drive mine in the winter. It gets pushed into the corner. -40 is hard on stuff and I have another truck to drive.

I have the melling high volume/high pressure pump. Cold start at 60psi. No noises. But scares me since it use to have 40psi hot idle pressure and now it has dropped. My pressure jumps right up to 40psi the second I touch the throttle. So that's good.

This was my filter from a few weeks ago.

 

I really want to just try a little thicker oil. But with 7months of down time. I think I am just going to pull the motor and check crap out. Can't hurt.

Your setup was running low pressure also? What was yours doing?

 

How many oil changes was at the time of you cutting open the filter?

Yeah, as long as your psi goes up with throttle that's a good thing! I'm not too worried about mine, but I am curious why it drops so much from cold start to hot driving temp! Losing 35+ Psi of oil pressure from cold to hot, just seems like a lot to me!

 

Not low. Just 25 at hot idle. Did some heavy reading and the consensus for gas turbo motors seemed to be 20w-50. Granted my motors stock and well worn in at this point. I'm abusing the hell out of it. I just wanted to be covered in the oil department. But after 500 miles on 5/30 and 15/40 (and everything in between) it would start to lose oil pressure across the board. My assumption was the heat was breaking the oil down. After switching to 20w50 it stopped dropping pressure after 500 miles. Still will go up to 70-80 at WOT. And probably 55-60 while cruising.

 

What is the point of the guys who insist on running an oil formulated for a diesel? Never understood that way of thinking.....anyway

I run a 4" stroke iron lq (408") in my truck. Run a procharger and is likely over 1000 rwhp (never dyno'd it though). My rod/main clearance is 0.0027". I run the 10296 melling with the bad mother ****** spring in it. I run a serviceable Purepower oil filter and Royal Purple XPR 20w-50 oil.

At idle hot the pressure is 48-50 psi. On a 1/4 mile pass, oil pressure reaches around 95 psi at the top of first gear, drops to around 76-78 psi at the shift points (ls pumps are notorious for dropping pressure over 5500-6500 rpm). After the shift it comes back up and then falls again. The datalog screen shot below was after the truck had made several passes and the air temp was around 85*.

On the first pass of the day when the oil is coldest, it'll see 110-115 psi of oil pressure.

In the screen shot below, this is a datalog showing only rpm (red line) and oil pressure (purple line) and the Y-axis is shown for both.