LS6 high oil consumption

[sbwrench]

Kevin,
Thanks for the links. I am familiar with that thread. That is the dry sump system I believe. His oil consumption problems are all high speed, high rpm where as mine is during normal street driving but was crazily apparent on the race track.

[Kevin Johnson]

That reply was for suggestions that the LS engine in general has not had examples of high oil consumption since 2002 irrespective of dry or wet sump oiling.

[sbwrench]

I thought this bulletin from GM was interesting; http://ebookbrowsee.net/290702d13029755 ... d158520468
They are advocating replacing ONLY the second ring and oil expander and leaving everything else alone, including bore finish.

[pamotorman]

I thought this bulletin from GM was interesting; http://ebookbrowsee.net/290702d13029755 ... d158520468
They are advocating replacing ONLY the second ring and oil expander and leaving everything else alone, including bore finish.

the problem was caused by using a low tension oil ring expander to get more HP. the second scraper ring was changed to help remove more oil film from the cylinder walls on the down stoke. the top rings are lapped to a cylinder by the ring manufacture before shipping to GM for engine assy so they did not want to chance a different ring or wall finish would muck things up.

[Kevin Johnson]

I am using a 6 qt. aluminum road race pan with a sump and trap doors to keep oil around the pick up in addition to a windage tray. It also uses a remote oil filter that is in the drivers side front of the engine compartment slightly higher then the pan.The lines hold an additional 1/2 quart.

Then, from last year:

Last night I went back to a petro based oil (non-synthetic) and marked the dipstick. It takes 7 quarts exactly.

Explain carefully how you arrived at the correct dipstick mark.

While you have the engine apart, now is THE perfect time to: 1) measure how far your dipstick protrudes past the plane of the oil pan rail; 2) fill your pan with 5, 6, 7, and 8 quarts of water and measure the distance, at the dipstick location, of the liquid surface from the oil pan rail (add the oil pan gasket thickness); 3) compare your mark to these measurements; 4) note the distance of the windage tray surface to the oil pan rail.

I just went through all this with a Dodge 2.4 with the balance shafts removed, the stock oil fill quantity, new windage tray design, etc. etc.

[sbwrench]

Kevin,
With the pan, lines and filter I come up with 7 but I like your method and will confirm on the rebuild. What are your thoughts on oil level in relation to crankshaft? What is the criteria for determining the full line on the dip stick? Once I determine what level in the pan constitutes full additional oil will be needed to fill lines and filter correct? So total oil = pan+ lines + filter?

[Kevin Johnson]

The running level of the oil for the pan must be well below the sheet metal baffle/windage-tray that covers the sump well in either the 7-qt steel sump or the 6-qt alloy sump on that website. If it is not well below that level then relatively minor changes in inclination will cause flooding of the tray. With a race pan, you also have to consider a change in the bulk density of oil when percentages of free air bubbles get mixed into it. Certainly you do not want a 10% air entrainment issue to cause immediate flooding of the baffle.

You have to be methodical about this: Fill the pan with quart increments of water and note when the water comes even with the tray. In stock pans the static full fill will typically just swamp the cover baffle. The running level will typically be 1-1.5 quarts under this to allow for oil in circulation. The shape/size of the sump well determines the incremental drop in height per unit volume. Typically this is not linear because the shapes are irregular. So "well below" can mean different quantities of oil for different pans.

[sbwrench]

Everything is apart and inspected. Tomorrow machine shop will measure bores and do a hone. Ring end gaps were very loose. Top ring was .020 to .024 and second ring was .031 to .034. Not sure why he set them up this loose. Wasn't planning on forced induction. Any suggestions on ring brand. I've had both Total Seal and Hastings recommended.

[Cubic_Cleveland]

I wouldn't worry about those rings gaps, they won't be the source of the oil burning. Total seal gets my vote for ring supplier.

Where does the breather go into the intake (if at all)? Can you get a better picture of the oily intake ports showing the back of the valves? Were new guides put in the heads? I'm leaning more towards the heads being the problem more than bore finish/rings just going by those intake ports. Do you have any photos of the bores?

[Rizzle]

Where does this fresh air vent I have boxed in your pick go to? Does the other valve cover have a vent as well, and if so where does that go?
It seems you have an ls6 valley pcv cover, so at least that should eliminate the early pcv issues as a problem.

[Kevin Johnson]

I wouldn't worry about those rings gaps, they won't be the source of the oil burning. Total seal gets my vote for ring supplier.

Where does the breather go into the intake (if at all)? Can you get a better picture of the oily intake ports showing the back of the valves? Were new guides put in the heads? I'm leaning more towards the heads being the problem more than bore finish/rings just going by those intake ports. Do you have any photos of the bores?

It would also be good if he could clarify what seemed to be stated: that the passenger side head had porting that exposed the rocker arm drillings as an initial source of possible leaking oil but the drivers side head porting did not expose these same drillings. He subsequently sealed the holes but this was after the pistons/rings in that bank had been allowed to seat.

[Cubic_Cleveland]

It would also be good if he could clarify what seemed to be stated: that the passenger side head had porting that exposed the rocker arm drillings as an initial source of possible leaking oil but the drivers side head porting did not expose these same drillings. He subsequently sealed the holes but this was after the pistons/rings in that bank had been allowed to seat.

The port would have broken through the rocker bolt boss on both heads.

sbwrench, what are the head castings?

[sbwrench]

Heads are 243 castings. Valve cover vents t together on passenger side front valve cover and go into the throttle body as stock set up. I tried venting them into a separate catch can at the track and it still smoked like crazy. Throttle body is clean and dry. Original builder replaced guides. When problem started the first thing I did was pull the heads and check stem to guide clearances and put new valve guide seals on. All 8 intake ports have the rocker bolts protruding into them, sorry if I wasn't clear on that.Backs of valves appear as new from being constantly oil washed same as piston tops on that bank. I will get requested pictures soon. Getting ready to clean the block and drop it off at the machine shop.

[Kevin Johnson]

Ok, the rocker bolts were sealed on one head but not the other when they were prepared. Or for some reason the rocker bolts on the passenger side head were removed after being initially sealed and not resealed. The high asymmetry of the problem points to something systematically done or not done.

In case I am not being clear I think there are at least three separate problems:

1) The initial problem of oil leaking from the rocker arm bolts into the intake ports on one side of the engine, hypothetically causing the ring seating on that bank to be improper.

2) Even if 1) was addressed by subsequently sealing the bolts the persisting ring seating issue on the passenger bank would explain high oil consumption in street usage. The extensive efforts by Heinz (coolchevy) to address a high oil consumption issue in an LS7 shows that despite good leakdown percentages (gas) rings can let a large amount of oil migrate past them (liquid).

3) High Gs at the track and blowing large amounts of oil smoke out during lateral G transition maneuvers but not during high rpm gear changes points to a separate issue with oil control in the pan. Lacking 1), 3) might never have been apparent.

[sbwrench]

Here are three pics; one of the bore where you can still see the cross hatch, one of the back of the intake valve on the oiled down bank and one of the exhaust port of the same head. Note clean spot like oil was migrating through the head? I'm tending to lead towards a head issue as well. Block is off to get honed and I will strip down head (again).