epix

iTrader: (2)

Posted a thread a bit back about low oil pressure in my newer 416 LS3 build and going through the build sheet I'm suspecting the root cause is due to having too much bearing clearance. Oil pressure starts out 45-50psi but once warm it will idle 6-10psi and often dip to almost 0 when deaccelerating causing the oil pressure dash light to appear. (I have replaced the pressure sensor and using mechanical gauge)

CLE-MS2199HXK (+.001 Extra Clearance) bearings were used on the build. Listed on summit as being 0.001" under size but apparently summit listed it wrong :\

I've always replaced and inspected the oil (Brad Penn or Valvoline VR1 20w-50) oil every 2k miles after the initial break in oil and have not noticed any metal specks in the oil.

Engine also runs a Melling 10355 Hi-Pressure pump, truck is AWD TBSS and has aftermarket oil pickup tube that is designed to diminish the effects of scavenging.

I won't know for sure until we pull the engine soon, but we intend to put the engine on a stand and remove pan to inspect the main bearings.

Would you guys just measure and replace the main bearings or better to dismantle the engine and inspect everything? If only the bearings need replaced with correctly sized mains does that need the crank to be polished/machined?

G Atsma

You might also check the oil pickup tube for a pinched O-ring. Very easy to miss, but very easy to have happen during assembly.

tech@WS6store

iTrader: (2)

I dont like that pump honestly. Why even use a high volume pump unless you need it? Adding that pump would make any extra clearance null reall esp the extra volume it puts out. Why run 20-50 also? Thats like pouring syrup in it. The company that designed the engine recommend either the pump or the oil?
Adding just a std 10295 to any std street built engine and 10-30 max is really the best.
It looks like you are having the issue when the oil heats up, which could be clearance related or could be internal oil leak issue like the valley cover o rings, cam thrust plate etc.

pantera_efi

iTrader: (1)

Hi Epix, Greg's good O-Ring "tech" could be complemented by stating that there are TWO O-ring sizes, one Black and one Blue.
Next Epic, I agree the +.001" mains AL LS-3 block could be another part of the problem.
Example : AL Boss 494 Ford Can-Am engine with ALUMINUM Caps = <.001".
The Main Bearing Clearance "grew" to .0025"+ when the block was at temp.

I use a Dial Bore Gauge to measure, block at room temp, with a "target" of .0020" to .0022" distance.
I modify the Oil Pan ports, ADD a passageway, to increase oil flow as they are 1/2 of the block bores.

I have "turned" Main Bearings into the block with crank in place, a 100% success.
I like the King Bearing "standard oil clearance" bearing finding a common .0022" MBC when measured.

Lance

tech@WS6store

iTrader: (2)

Normally those kalico coated bearings take up an extra clearance so that is why they are mostly bought in an X as well to take the clearance back.

G Atsma

FYI, he is running a high-PRESSURE pump, not high-VOLUME.

tech@WS6store

iTrader: (2)

10355 is a high volume and high pressure pump that provides more volume than the 10296. Its intended for vvt/afm setups.

G Atsma

Oh OK. Just went with what was said above in the 1st post. Good call!

tech@WS6store

iTrader: (2)

That is also why i do not like nor recommend it. Most that want a perf pump get the 10295 or 10296. Most engines dont need the extra volume and it can sometimes agitate pcv issues and other things. The 10295 fits most applications just fine although some like to use the 10296 with the lighter bypass spring. The jury is still out on that but seems to work.

G Atsma

LIGHTER bypass spring?!?! LOWER pressure??? That runs against the "oil pressure gospel" I've known most of my life. lol But hey, these LS engines are a new ballgame against what went before!

tech@WS6store

iTrader: (2)

Within a fixed bore size like oil galleries and bearing clearances, increasing volume will normally also increase pressure. The way stock pump bypasses work, it bleeds internally back into the pump. Then it recirculates it back into the system. The pressure is then metered lower but is still a little higher than normal due to the increased volume. Some like it, some do not.

G Atsma

That DOES make sense, but as you say, I'm not sure the added pressure needs to be "relieved", unless there is the chance of something rupturing due to the extra volume causing the higher pressure. Not sure that could happen though.

tech@WS6store

iTrader: (2)

Oil seals can and do blow out as well as dipsticks. If it does it internally like the valley cover o rings on the gen4 blocks youll never know.

G Atsma

True, but wouldn't the pressure have to be unusually high to cause any of that? Here we are talking about the higher pressure a high volume pump puts out as a "side effect" of higher volume.

tech@WS6store

iTrader: (2)

There are threads all the time and on other places on here of guys blowing out dipsticks and having issues like that. In nearly every build they used a high volume pump. It also agitates pcv issues as well and can possibly lead to oil ring issues. That extra volume has to go somewhere at the end of the line.
Id like to give a better answer as to what oil pressure is in the cam galleries and to the mains and rods but i do not. I would like to know that info. The pressure bleeds off at every spot and, with change in direction, flow decreases also.
It gets quite complicated. Then factor in the bypass in the pan as well and in the filter.

G Atsma

OK, I learned a lot here! Thank you for your time. Until now, I always thought a higher pressure &/or volume pump was SOP in an engine build. But all you said above makes perfect sense! Thanks again!

tech@WS6store

iTrader: (2)

I prefer the higher quality 10295 and 10296 pumps but if your budget cannot handle that then that is why we offer the better caste hi flo and ported high flo pumps. I offer either choice and explain why to guys looking for oil pumps with cam kits etc.
Sometimes they like the cheaper pump, sometimes they want the best quality. The best quality is the melling 10295/6. The choice is yours from there. We can port them also to allow for less pumping loss, but all of that is another discussion for another time.