Tommy Boy

The best thing to do is probably a leak down test with a leak-down guage to determine if the rings or the heads are where the seal is being lost. Do this BEFORE you dissamble the engine. It will be much easier to access the spark plug holes with the extra room. You should be able to rotate the engine with a breaker bar off the crank bolt to get each cylinder to compression stroke. Then just take your readings. You will need at least a small air compressor to provide the compressed air. It will be much easier to determine where the hissing sounds of escaping air are coming from (intake manifold or exhaust manifold or after removing the oil pan, the crank case). Don't forget to record your readings from each cylinder. Most new engines have 2-5% leakdown, most worn-out engines have readings of 10% or more. Let us know what you find!

MaxSE-R

i think my oil loss is coming for a bad valve cover seal, because when i changed my spark plugs about 10k miles ago, one of the spark plugs were covered in oil. but if you guys find something else let me know so i can take a look at that to see if that is another cause of the oil burning problem.

irish44j

iTrader: (38)

Or you could just get an 00-01 and get the 30 extra horses with the same smoothness.....

(and the better looks )

BewstAdd1ct

$5 on scored cylinder walls.

take plenty of pics, number **** and mark for position as you disassemble.

leakdown readings might be nice too.

GBAUER

iTrader: (2)

Mine was bad too, but not 1 qt/ 300 miles bad!

the valve cover gasket failure is very, very common, but it doesn't typically leak bad enough to notice.

GBAUER

iTrader: (2)

I won't take that bet....

GBAUER

iTrader: (2)

Another update: I should be getting the car back today (minus headers, udp and the IM gaskets...... at least the salvaged engine has good pre-cats for the time being). Unless the engine is already torn down by redline, I'll try to play with it and my camera today if there's enough room for me at the shop. I'll throw down $500 on the cylinder walls being scored.

Jasovanni

iTrader: (1)

Yeah, my 2cents: If you were getting smoke, its most definately something relating to the piston rings/cylinder walls. The only real way to burn oil is to push it past the rings, or drip down into the engine through your valve stem seals. You might consider looking into aftermarket piston rings and doing a quick rebuild on the old motor. Thats if it wasn't injured too bad when it "blew". (or is redline paying you for the old one?) Have it bored out .30 over or so to fix the inconsistancies in the cylinder walls. At that point you're going to need .30 over pistons or you'll be burning even more on the rebuild. Be sure to watch the allignment of the gaps in the rings on install. I personally think if you got a high quality crosshatch finish from a good machinist doing your boreing, along with a good set of rings, they should seat well, and give you a 250k+ engine. You KNOW it would be a fun project.

My bet is that nissan's issue here is just shortcutting on the piston ring material and/or a weird surfacing procedure on the bore.

I figure it could be even simpler than that....perhaps the rings simply don't seat well if the car isn't broken in properly when its new.....

If you can't find anything to put the old motor in, consider building a small formula car or something.....

Best of luck man, hope the swap goes well! Props for doing it yourself!

J

VQ30GTR

smoke at WOT- White? If so maybe head gasket.

BewstAdd1ct

speaking of the old engine...

what ARE you gonna do with it?

GBAUER

iTrader: (2)

I'm (or we...) am/are rebuilding it and doing some little internal things I don't want to talk about yet...

Got the car back today. I haven't had power like this for a good year! Played cat and mouse with a IS350, but we won't talk about that....

It's obvious to me that the pre-cats were failing for a long, long, long time. I'm guessing around 100k miles (I have 165,000 on it now). The headers, UDP, urethane motor mounts and plenum spacers weren't ready yet, so we used the pre-cats from the salvaged engine which were fine. Hopefully within a month or so we'll do the headers and the rest. Corey (Redmax) and I will be tearing down the old engine soon, but we want to take our time testing it and documenting everything for everyone's use. I still think we're going to find out that the chicken indeed came before the egg in that the pre-cats caused the oil consumption.

SoonerFan

iTrader: (5)

well hurry up!!! i only have 6K left on my warranty and want to take the dealership some proof so they dont keep blowing me off

NmexMAX

iTrader: (22)

What are pre-cats? Headers FTMFW...Looking foward to see your progress...

GBAUER

iTrader: (2)

Do you have a dipstick? Do you put oil in your car? What other proof do you need? If you have consumption, go to another dealership if they won't help you out. Come up to Fredneck and we can go over there. Some of the guys are getting to know me (or at least my car) and we can explain the situation together. They can do a consumption test and see the oil level.


BTW: I thought you had headers? If you do, are you still using oil? If so, that shoots my theory in the head and kills it with a dull spoon.

GBAUER

iTrader: (2)

Error404: header source not found FTL....

Having trouble finding headers now. We might have to make our own.

nismology

iTrader: (8)

Yea i would say the same. Either the rings are no good or the honing technique is suspect.

BewstAdd1ct

okay, so then youre throwing the old engine back in?

what about the new one, after it comes out?

Y2K2Driver

iTrader: (1)

Excuse my ignorance, but how do pre-cats cause oil consumption?

AllGo

iTrader: (1)

I assume they mean the precats began to fail/breakup and some of the cat material ended up getting sucked back into the combustion chamber as there is really no where else for it to go. These cats are about 6 inches deep and the top part that gets the most unburned fuel and most heat seems to be the part where these precats deteriorate. I put headers on my car at 36k mainly for this reason and the power gains aren't bad either.

GBAUER

iTrader: (2)

Join the list of people wanting it....

Actually I'll probably keep it as a spare since I'll be pushing the other so hard.

Tommy Boy

After you do your initial visual/leakdown investigation it would be interesting to bring the block to a quality machinist to have them measure each bore diameter and also check bore runout or taper. This might help to determine if piston rock via detonation could be a factor. You could also due the same to the pistons to see what your overall piston to bore clearances were.

GBAUER

iTrader: (2)

Now you're talking real money and time...

SoonerFan

iTrader: (5)

i meant proof of whats causing the problem, they did an oil consumption test and agree that its losing oil. but they say they dont know what would be causing it...like they are suprised and dont know that its ever happened before. i just need to take it back to them so they can "remove the valve covers and see if they can find the problem"
and i dont have headers...im another one of the people that should have got them when they were easier to get

Nomad

iTrader: (5)

George any updates?

chr0nos

iTrader: (1)

bump for updates.

SoonerFan

iTrader: (5)

related...i just dropped my car off at the dealership (see my post above)
i will let people know what they say caused the problem with mine

abakalen

iTrader: (1)

So, what was the diagnosis?