OK, so here is my take. On the 350Z motor:

It has a micro finish on the cylinder walls. It still needs a break-in period. Only like 1200 miles however. Hence the break-in requirements set out in the manual. After that period of time the rings and cams should be worn in properly.

You see, what happens if you change to synthetic oil before the rings seat is that you will burn oil for a long time and the compression will be lower. It changes the way the motor seals and you don't get as much compresssion ever since you are always burning the oil past the rings. If you wait until the motor is broken in and the rings are sealed and then go to synthetic doesn't hurt the compression of the motor.

I have a good example of many people going to synthetic on LS1 motors and they burn oil like it's going out of style. I waited until 10KK to put synthetic oil in my LS1 and it burns less than 1/4 quart per 3K miles. That is racing the car at the drag strip of over 100 runs per 3K miles.

So, I did the same with the 350Z. I let her break-in for 5K (1200 miles is what Nissan recommends) and then switched to synthetic. I do not burn oil and the compression is all there. I just wanted to make sure the ring were completely seated. The other way around.... you burn oil.

It would be nice to see HP differences at 10K miles with a motor run with Syn from day one and one that changed over to Syn at 5K. I think you would see a 10-15HP difference between the two. JHMO

Point is after the motor has made it initial seal it's OK to run Syn. If you don't allow it to seal initially, it may never seal completely and you'll burn a little more oil than others. It's very similar to ring wash out caused by too much gas. If you don't do these things to accomplish the compression and you lose power, oil and gas in the process.

Hey, just my take on it......

BTW- I own a VQ motor in my Pathfinder and it doesn't burn any oil either.
I broke it in the same way. Switched to Syn at 5K and she's still running like a top. One of the main reason I bought the 350Z is for that wonderful VQ motor and the mileage I got out of my 300ZXT (VQ based on). I mean 200K for a turbo motor? That's unbelievable!!! It's just one of the best motors ever made. Just make sure you install great oil filters in them. Factory ones work great. That is the only condition we have seen these motor mess up beside abuse. Oil starvation from a oil filter that comes apart.

 

i thought zs come with syn. oil? or is it regular engin oil? i would do what Z driver said since paitents is the key to life.. HAHA

 

How do you explain the fact that EVERY LS1 Corvette that GM ever produced left the factory with Mobil 1 in it? My 2000 Camaro SS was on Mobil one right away and never burned oil.

 

My 04 Evo VIII had Mobile 1 from the factory and every oil change was covered and was synthetic.

 

+1

 

Here's my question to all of you who say my car came with Mobil 1 from day one. Can you prove it? It's one thing to say it but another to prove. Does it say in writing that it has mobile one in it on some form that you recieved when you bought the car. If not then you have no clue what it came with. Just what the salesman said, and they will say anything to get you buy their cars. I had a salesman tell me the evo was twin turbo'd. Another salesman tell me that the 350 in 350z was for the horsepower! So unless you watched them pour mobil one in the car, you have no real proof. All the oil begins to look the same after a few miles!

 

Mobil 1 is the factory fill engine oil for Corvettes. And Starting in October of 2001, all LS1 engines get Mobil 1 from the factory.

After the aluminum block and plastic intake, the most noticeable part on an LS1 is the oil pan. Sources involved in C5 testing call the intricate aluminum casting a "bat wing" pan. It's part of the lower engine structure and contributes to overall cylinder case rigidity. Gen III continues the recent tradition of little oil filters but the filter mounts on the rear of the oil pan rather than the block. As with LT1/4s, no oil cooler is available and the factory fill will be synthetic oil. Testing shows the oil temperature range to be similar to what we see in Gen II Small-Blocks.

http://www.idavette.net/hib/ls1c.html

 

As far back as '91, GM was REQUIRING synthetic in some engines for warranty. My Syclone is an example of this.

I've always switched to Mobil 1 at my first oil change. My 124,000 mile GTP had that, and it still doesn't burn oil (slow leak, though, but less than 1/4 to 1/2 quart per 4500 mile oil change).

 

Good info on the LS1 motors. That is what i prefer to see, hard proof then hearsay. I appreciate it, so that covers the LS motors what about the other cars & makers?

 

2003 Mitsubishi Lancer Evolution VIII

ENGINE SPECS


Engine Type 2.0L I-4 Intercooled Turbo
Engine Code 4G63
Valve Train DOHC 16-valve
Displacement (cu.in./cc) 121.9 / 1997
Bore x Stroke (in.) 3.35 X 3.46
Compression Ratio 8.8:1
Horsepower @ RPM (BHP) 271 @ 6500
Torque @ RPM (lbs-ft) 273 @ 3500
Engine Block Cast Iron
Cylinder Heads Aluminum
Redline RPM 7000
Valve Cover Magnesium
Fuel System ECI-MULTI electronic fuel injection
Recommended Fuel Premium Unleaded (RON98 )
Engine Oil Type 100% Fully Syntheic Oil Required (Mobil 1 factory fill)
Engine Oil Capacity (qt) 4.8 (0.3qt filter; 0.3qt oil cooler)
Turbocharger Type TD05HR-16G6-9.8T (Twin Scroll Turbine)
Boost Press (WOT/3500) 19.00 psi
Boost Press (WOT/6500) 16.24 psi

http://www.mitsubishicars.com/evo/popup_tech_specs.html

 

Mobil 1 is factory fill in:
* Aston Martin
* Bentley Amage and Bentley GT
* Cadillac CTS, XLR, SRX and STS
* Chevrolet Corvette
* Dodge Viper
* Mercedes-Benz AMG vehicles
* Mercedes SLR
* Mitsubishi EVO
* Pontiac GTO
* All Porsche vehicles

http://www.mobil1.com/USA-English/Mo...rs_Choice.aspx

 

I don't know if "Break in" oil is an old wives tale but I don't think it's been used in cars since the oil filter was an option. It was a thin non-detergent oil.

 

I bought a 93 Master Craft boat new with a Corvette LT1 engine in it. The engine was shipped with 5W30 Mobil 1. I changed the oil every 50 hours and had oil analysis run on every oil change. Each oil analysis would come back with some level of gas in the oil. The gas was up to 6% on one analysis. After about 200 hours and several changes to lean the ECU, Master Craft had me replace the Mobil 1 with conventional oil for 50 hours for a break in then back to a 15W50 Mobil 1. It worked; the gas in oil problem was fixed.

They run boat engines run cooler than car engines as the cooling system is not pressurized and it runs water with no antifreeze. Car oil gets hot enough to evaporate any gas that may blow by into the oil, so don't worry about your cars with Mobil 1. My vote is with the mechanic, break in with conventional oil.

 

My brother had a new 91' 300zxtt and it had a mobil 1 badge under the hood and has do the Porsche I think that should be prove enough that these cars come from factory with mobil 1. I have a 90' 300 2+2 with 193k miles and have been using Royal Purple for years. I also have a 06' 350z with 2k miles and I will change to Royal purple at 3k, concidering i went 140mph sunday I'd say the rings are ready.

 

On the Evo's oil cap it says use only Mobile 1 synthetic. It is also stated on the paper work with the car.

 

i honestly dont think it ****in matters. but hey, thats just me

 

It matters. Nissan was (probably) trying to save $ on oil so they didn't use synthetic...so once you get a chance, slam Mobil 1 5w30 into her

 

all this info is fairly easy to find. No guessing needed.

There is no break-in oil used in the VQ. Here's an oil analysis of a brand new VQ and the first oil
http://www.g-owners.com/pic_display.asp?id=537

Also, with the help of oil analysis on the VQ35, we know that metal wear does not settle down until 5-10K. With city driving, its around 5K... with more highway, its near 10K. It's only after this wear settles down do you make a bit more HP and have better MPG. Why delay that by switching to syn too early?

Some of you are correct about some cars not needing break in anymore. Honda and Toyota are settled by 500 miles. And cars coming with syn from the factory are different animals. The VQ is still unique in a few ways. But we dont really have to guess, alot of owners have been sharing their oil analysis for several years. Its very easy to see trends and make up your own mind.

 

Hey tware where in LR are you? Do you work at the base as well? I drive the silver nismo.

 

I live/work in west Little Rock. I saw you at CompUSA about 2 weeks ago, parked next to another Z. If you recall a b.silver G coupe parking behind you, that was me. At least I assume it was you, I dont recall many Nismos around here. I think there is a silver convertable with nismo wheels and thats about it.