2005 Corvette

[bbobynski]

While the official answer is that the factory oil fill is nothing special....just plain 5W30 Mobil 1 just like you get in the store...the fact is that the engine was assembled on the assembly line with a small amount of ZDP rich assembly lube applied to critical surfaces as assembly lube. Cylinder walls, ring, ring lands, bearings, cam lobes, etc. all receive local applications of a Lubrizol assembly lube product an/or EOS. This assembly lube probably totals around 6 ounces or so total for the engine. This obviously protects against local scuffing or wear during the initial few seconds of operation and then the ZDP rich assembly lube is washed into the oil and contributes to spiking the factory oil fill with extra ZDP....so....in fact, the factory oil fill does, by default, have slightly higher levels of ZDP to guard against breakin wear. Removing this oil and changing early does put less ZDP in the oil for the breakin miles that follow.

It is probably not a big deal at all because the ZDP additive is fairly small, most of the purpose of it being in the oil is covered by the first few miles of operation and new oil would have a certain level of ZDP equivalent to the factory fill oil anyway assuming some of the extra ZDP was used up during the earliest moments of breakin.

But, the fact is that the factory oil fill is a bit "special" having that spike of ZDP rich assembly lube in it.

If you must change early for piece of mind, you could add a pint of GM EOS to the new oil fill to replicate the assembly lube addition to the factory oil fill.

Personally, I would just run the factory oil fill to the first change interval. If you do want to change early, follow the oil life monitor and change at 50% oil life or something like that for an early first change. Changing at 500 and 2000 is a waste of time and money as the oil in the engine at that point is perfectly fine. It won't hurt to change it, especially if you add the EOS but it really isn't going to help anything, either.

I have seen a lot of factory engines torn down after running lots of miles with the factory oil fill and they look perfect inside with no harm done whatsoever by running the oil to the first full oil monitor change interval.

 

[1911]

quote:

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Originally posted by 1 FMF:
It is because the engine runs hot, typically coolant temps 200-220F and with the body style being what it is having less than optimum radiator and engine bay cooling and electric fans not coming on till coolant is around 220F you will see 220+ oil temps routinely, as opposed to the old 350 chevy with 160F thermostat and fan running off the crankshaft serp. belt. And this isn't when you're driving the car like it's made to be driven! My camaro has no problem running 240F oil temps during the summer in slow moving traffic, and I've had the gauge go past 260F plenty of times (with 220-230F coolant temp).
If you were asking this question a few years ago, I'd say it's a must to go synthetic because of the high oil temps, but today's "dino" oils are way better than yesterdays and will handle high temps better.

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No disrespect but this cannot be true because Doug Hillary said that modern cars do not really run any hotter oil temps than cars did in the early 1940's. This is despite their having 2 to 4 times the specific output, having drastically reduced airflow around the engine exterior itself (underhood flow), and radiators that are small and barely exposed to good direct airflow(check out the front of a 1994 Honda Civic!!!)...trust Doug....not yourself and your oil temp gauge

 

[bbobynski]

quote:

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Originally posted by Chris B.:

quote:

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Originally posted by bbobynski:

Changing it at 500 and 2000 is a complete waste of time and money...unless a year goes by and that is all the miles you wrack up....LOL

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That is not true. Lots of engine builders reccomend that you change it at the 1st 500 and again around 1,500-2000 miles. I have done this with all my cars and they NEVER burn oil later in life. It is good to keep fresh oil in the engine during break in plus if there are any break in type of shavings it will get them out of the engine.

Change that Vettes oil at 500 miles for sure!!!

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Welll Chris......GM builds more engines PER DAY than any engine builder quorum you will be able to put together can build in a YEAR.....and GM says drive it until the oil life monitor tells you to change it. Maybe other "engine builders" leave more trash in their engines to be cleaned out or they do not provide the OEM equivalent surface finishes or maybe they are just skeered of the little jewels that they have built blowing up. Whatever the reason, if you are looking for input from a REAL engine builder, GM says to leave it alone. Certainly if it is a racing engine that is going to be run at very high RPM so as to bypass the oil filter regularily, then I would agree with you to some extent...but....for a passenger car, even a Corvette, follow the oil life monitor.

I agree, if it is peace of mind it is just an oil change and can do no real harm...but...don't beat up on people that don't change the oil immediately with a new car...it really isn't necessary.

 

[bbobynski]

quote:

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Originally posted by 1 FMF:
The GM 4718M spec placed on the corvette, and other models, requires oil to do better in high temp high shear conditions and have less oxidation at high temps. This should be obvious when you think about it. It is because the engine runs hot, typically coolant temps 200-220F and with the body style being what it is having less than optimum radiator and engine bay cooling and electric fans not coming on till coolant is around 220F you will see 220+ oil temps My camaro has no problem running 240F oil temps during the summer in slow moving traffic, and I've had the gauge go past 260F plenty of times (with 220-230F coolant temp).
[/QB]

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The GM spec for synthetic was incorporated for those applications for protection when the oil gets over 305 F....up to then we consider the conventional oils on the market to be fine for occasionaly spikes to 305.

240..??..260...???...that is NOT hot oil. I would say that the best thing that you can do to your oil is to get it to 250-260 each time the engine is run to make sure all the moisture and contaminants are thoroughly boiled out. HOT oil is when it is regularily getting to 290-300. We have demonstrated time and time again conventional oil's capability to occasionally spike to 305 with no problems. It will shorten up the oil life monitor a bit due to the more rapid oxidation rate incorporated in the model but the oil will be fine. If you think that you need a synthetic for getting to 260 F then you have been mislead. Period.

 

[bbobynski]

It is a bit off topic but I will share this anecdote if you are worried about breakin on a new production engine.

We did a program back in the mid 90's to determine what sort of engine "hot" tests worked best and to investigate a number of other things. The "test" was done thru Jack Roush's engineering group and contracted on their dynos. It involved taking 150 brand new, 300 HP Northstar engines that had never been fired and running a 2.5 hour hot torture test on them with a post test teardown. The engines were stone green at the start of the test. They were each installed on the dyno and the coolant and lube systems hooked up. Coolant was preheated to 255 F by the test cell equipment and oil was preheated to 285 F. This was done with 50/50 DexCool/water and conventional motor oil...not synthetic. The engine was fired and IMMEDIATELY put at full throttle where it ran at 6000 + RPM at full load with the oil temp controlled at 285 to 300 F. It was harder to get the dyno equipment to live than anything else....LOL.

There were no engine failures at all. None. All engines were torn down and judged to be in "like new" condition on all parts. No scuffed pistons, no damaged bearings, nothing. In fact, it was difficult to tell that most of the bearings had even been used as they absolutely looked brand new even under magnification. To say that it was eye-opening to a lot of people was an understatement. The Roush dyno techs thought that we were nuts and would stop after the first few engines blew up....LOL.

The only caveat here, is that each engine had the oil routed thru the oil heater and oil cooler equipment which necessitated separate filtration so that any debris generated during the first few minutes of operation that might have bypassed the filter otherwise running at 6000 was caught by the external filtration (it was needed to protect the cooler/heater heat exchangers if there was a problem) so the test indicates performance of fits and finishes of a brand new engine and oil capability at those temps and such but doesn't perfectly replecate a car run immediately to full throttle, 6000 RPM and held there for 2.5 hours..as if you could do that somewhere....LOL.

I was the development engineer in charge of this test so I saw it happen, saw the engines at teardown and compiled the results. Anyone concerned about stabbing the throttle during break in can rest easy. Trust me.

 

[BarkerMan]

You guys are making this all too complicated. In the first 30 minutes or so of an engine's life, it should be run with no load at about twenty five hundred rpm. This gets everything that depends on splash oiling handled and makes sure that eveything else is turning and sliding ok. After that have at it. Any time at idle or over 2.5k or with much of a load is extra wear and contributes nothing to a good start in life for the engine. If you are buying a new car, do what you can, if you are building an engine you've got control of the process and you can do this kind of start up. Other than that you just take what you get. An early oil change, under 1k miles is a good way to see what's going on. By 1k miles you don't need any break-in anything, in the oil or in the driving. You new car got its rings seated driving off the transporter in onto the dealer's lot, if they were not seated on the first start up. The old days of pouring Bon-Ami down the carb to seat the rings is history. DThumper, congrats on the purchase of your new Corvette, and use the Mobil 1, don't invent a problem. The only thing I would do is be sure to run the Mobil 1 oil filter, it is a very good filter and worth the extra few buck. Just make sure you wave when you blow past me on the freeway. I really like that car.

 

[bbobynski]

Possibly good advice for an older engine with flat tappets that relied on splash oiling for the cam lobes to live. The LS1 style engine in the Corvette has roller followers, no distributor drive gear and roller rocker arms. Nothing to "splash lube" so spending time idling above 2500 is time wasted. Absolutely nothing to gain, there.

There is some fallicy in the ring breakin advice. I agree that the ring breakin to the cylinder walls happens very rapidly and your comment about the time to the haulaway truck is pretty accurate. The main thing that needs to breakin with the rings is the SIDE of the rings to the SIDE OF RING LANDS. That mating surface is critical for good sealing and the ring motion against the side walls and gas pressure loads against the side walls is what breaks in the rings to the ring lands. This is especially critical in todays engines that have the top ring closer to the top of the piston and that have hard anodized top ring lands for poundout and wear prevention. Hard anodizing of the ring lands leaves a "pebbly" surface when viewed under and SEM. That surface must be burnished smooth for good ring seal and the hard anodized surface is tough to burnish down. It takes load. To really break in the rings against the side of the piston ring lands it is helpful to apply full load for brief intervals and then allow heavy engine braking to load the rings the other way and cause them to move around on the piston so as to burnish the sides of the ring lands.

I often recommend a procedure that can be done on the expressway by putting the trans in a manually selected lower gear so that the car is about 4500 RPM at 45-55 MPH. Full throttle up too 5500-6000 and then lift and allow engine braking back to 4500. Do this 10 times and then drive normally to cool things off. Repeat. Do this several times on several consequtive days. This is excellent for braking in the rings or exercising the rings on an older engine that might have carbon deposits restricting ring motion causing poor oil economy.

 

[Ugly3]

bbob - You can not imaging the awe I feel reading your informative and authorative posts. Great information keep it coming.

Now if you could come to the oil filter section and share your experiences we all would appreciate it.

Thank you.

 

[Mike_dup1]

bbob, Can you answer this??

Why does the LS1 knock when its cold? What is causing this?

My 2002 Trans Am has done it since about 7000 miles and my friends 2002 Vette makes the same noise yet his is not as loud as mine. He had over 40,000 miles but I only have 19,500. Only get to drive about 6 months in da UP. I was at Bowling Green in 2002 (F-bod gathering) and spoke with many LS1 owners. They all had the same thing to say (they all knock) and the GM people there would not address this issue that I was privy too. All I recall them saying was that they went to installing Mobil 1 in the 2002 models but why I never found out. S.S. is the on who said that.

 

[Geoff]

I have always liked GM engines and bbobs posts are good news.

We see a lot of silicon in factory fill UOAs, particularly with sand-cast aluminum components. Not sure if it can all be attributed to sealers.

I like the early change at 500 miles idea purely for the peace of mind that any dust from the assembly process is removed (smaller than the filter's threshold), then as bbob recommended adding the GM EOS especially if using GF-4 oil.

Just say no to silicon - except the kind used for anti-foaming.

From disassembly on engines I have done - just 2 after many miles - you can clearly see where particles have scuffed the bearing shells or "wiped" off the babbit.

 

[TheFuror]

quote:

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Originally posted by DThumper:
I am new to your site but I have done some searching before I registered and couldn't find my answer. I have a new Corvette on order (C-6) and the owners manual calls for an oil meeting GM 4718M. I am 46 years old and have heard both sides of the debate concerning the use of a full synthetic oil in a new motor. My question is this: I will change the oil and filter at 500 miles and then again at 2000. If I do this will I be OK with using a dino instead of synthetic? Is there a dino oil that meets this standard (I couldn't find one)? If not, will my car use oil later in its life due to the use of full synthetic when new? Thanks for your help in advance.

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Ah man, a new Corvette?

Tell you what: let me borrow your car a few times a year and I will pay for the Mobil 1 instead of dino oil.

Bob W.

 

[Bob The Builder]

Well, i thought that I would add my own 2.7 cents and say that I have a 1996 Toyota Tacoma which I might add is performance wise, very similiar to the Corvette.

j/k I did want to mention that I have run pure synthetic oil in my truck, essentially since new, and the engine has demonstrated absolutely no wear on internal components as verified by an unneeded valvetrain adjustment

check, and by a oil pan gasket change (caused by deformed gasket) as well as a cylinder leakdown (compression) test which showed even and normal readings across all cylinders. Additionally, it don't burn nuthin! Synthetic man! It's the wave of the future. Run it like you brung it!

BtB

PS. I just wanted to acknowledge a recent shipment of the "green stuff" by a fellow BITOG'er! Thank you everyone!

PSS. I agree with bbobynski's method of ring breakin posted above. I did that with my Tacoma, and with my 72 Camaro after I built the engine for her.

[ April 21, 2005, 02:22 PM: Message edited by: Bob The Builder ]

 

[bbobynski]

Keep in mind looking at a lot of the OEM bearing shells at teardown....many of them have a very thin tin overplate to act as a break-in buffer or barrier to protect the "babbit" if the crank is rotated during assembly and the bearing is dry. The tin overplate is extremely thin and dull looking but it can make the bearing appear to be "wiped" or partially scuffed. The tin will burnish away in spot as the crank turns leaving some nasty looking but totally harmless "scuff-like" markings. This is primarily a characteristic of OEM bearings as most of the aftermarket bearings do not have the tin overplate. The tin overplate does create a deceptive appearance after first running the engine that has often been mis-read as a potential scuffing or wear when, in fact, it is harmless.

 

[moribundman]

bbobynski, this tidbit about the tinplate on new bearings is very interesting. So far nobody has ever mentioned that here.

Seems like you might be the man to tell me if lead-free bearings are actually being used in modern motors and if so, why do we see lead show up in essentially all UOAs? Federal Mogul keeps talking about producing lead-free bearings and at least some Euro carmakers claim to use them. What's up with that?

[ April 21, 2005, 04:48 PM: Message edited by: moribundman ]

 

[Ilikesynthetics]

quote:

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Originally posted by bbobynski:
Possibly good advice for an older engine with flat tappets that relied on splash oiling for the cam lobes to live. The LS1 style engine in the Corvette has roller followers, no distributor drive gear and roller rocker arms. Nothing to "splash lube" so spending time idling above 2500 is time wasted. Absolutely nothing to gain, there.

There is some fallicy in the ring breakin advice. I agree that the ring breakin to the cylinder walls happens very rapidly and your comment about the time to the haulaway truck is pretty accurate. The main thing that needs to breakin with the rings is the SIDE of the rings to the SIDE OF RING LANDS. That mating surface is critical for good sealing and the ring motion against the side walls and gas pressure loads against the side walls is what breaks in the rings to the ring lands. This is especially critical in todays engines that have the top ring closer to the top of the piston and that have hard anodized top ring lands for poundout and wear prevention. Hard anodizing of the ring lands leaves a "pebbly" surface when viewed under and SEM. That surface must be burnished smooth for good ring seal and the hard anodized surface is tough to burnish down. It takes load. To really break in the rings against the side of the piston ring lands it is helpful to apply full load for brief intervals and then allow heavy engine braking to load the rings the other way and cause them to move around on the piston so as to burnish the sides of the ring lands.

I often recommend a procedure that can be done on the expressway by putting the trans in a manually selected lower gear so that the car is about 4500 RPM at 45-55 MPH. Full throttle up too 5500-6000 and then lift and allow engine braking back to 4500. Do this 10 times and then drive normally to cool things off. Repeat. Do this several times on several consequtive days. This is excellent for braking in the rings or exercising the rings on an older engine that might have carbon deposits restricting ring motion causing poor oil economy.

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As an engine builder myself, this is the best advice I have seen so far for this particular engine.

 

[buster]

bbobynski, what is your take on breaking in the engine hard in the first 20 miles? Thats been a controversial subject on most websites. Most manuals state to wait about 500 miles before going over 60mph and flooring it. Some have said flooring it as soon as you buy it is good for it.

 

[bbobynski]

quote:

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Originally posted by Mike:
bbob, Can you answer this??

Why does the LS1 knock when its cold? What is causing this?

My 2002 Trans Am has done it since about 7000 miles and my friends 2002 Vette makes the same noise yet his is not as loud as mine. He had over 40,000 miles but I only have 19,500. Only get to drive about 6 months in da UP. I was at Bowling Green in 2002 (F-bod gathering) and spoke with many LS1 owners. They all had the same thing to say (they all knock) and the GM people there would not address this issue that I was privy too. All I recall them saying was that they went to installing Mobil 1 in the 2002 models but why I never found out. S.S. is the on who said that.

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Are you talking about piston slap during the first few minutes of warmup..??


If so...that is what it is. Nothing to fear or nothing really wrong...just the piston noise until the piston warms up to fill the clearance to the bore.

Pistons rock as they cross TDC where the thrust load from the rod angularity shifts from one side to the other. This makes noise. Harmless..but it is the source of piston slap in most all situations.

To prevent this, pistons are designed with long, tapered, flexible skirts so that they can be fitted very tight in the bores when the bore and piston is cold. The taper of the skirt and flexibility of the skirt then prevents scuffing when the piston is hot. Also, the piston pin in OEM production pistons is always offset to one side....it is NOT in the middle of the piston. By offsetting the pin in the piston, artificial thrust load is created to control the piston "rocking" as it crosses over TDC.

Unfortunately, all of the above control techniques, common in past model engines to the extreme, create excess piston mass, cause friction and cost power and fuel economy. With the desire to build in as much power and free-revving capability and to improve fuel economy as much as possible thru friction reduction these design features are pushed in the other direction on modern engines.

Piston pin offset has been reduced over the years to a bare minimum today to reduce the thrust load generated and reduce friction. Pistons have been lightened up considerably by shortening the skirts. This creates less rotating/reciprocating mass which is good for power, free revving capability and fuel economy. Light weight pistons are great but the skirts, by necessity, are short making it hard to make them both strong and flexible and the shorter ckirts make them more prone to rocking.

Unfortunately, when the performance and fuel economy oriented pistons are run cold they are very prone to "slap" until they warm up to operating temperature.

The piston designers and development engineers are always treading the fine line between piston slap cold and friction and power/fuel economy loss when the engine is warm.

It is possible that you are hearing piston noise from an engine that is on the "high limit" for piston clearance so that it makes some noise cold. The good news is that the condition is harmless and that engine is probably a little more powerful (due to less friction) than a "quiet" counterpart. The bad news is that...it makes noise cold.

As an example of what the piston pin offset can do, it was common back in the early 70's to turn the pistons around "backwards" in the large displacement Chrysler engines to gain power. Those engines had large piston pin offsets to create thrust load to control the piston slap. So much thrust load and friction was created that just turning the pistons around in the bores was often good for 10 HP. The engines were very quiet with the pistons in correctly and they slapped like crazy, especially when cold, with the pistons reversed so as to reverse the pin offset.

Racing engines do not have the pin offset and thus the pistons slap like mad...but no one hears them over the open headers...LOL.

The noise is an annoyance but will not hurt anything and the engine is fine.

I don't remember if that engine had full floating pins or not but they can also cause some ticking just after start. Same sort of deal...the "correct" clearances in floating pins will cause clicking after startup for 30 seconds or so. To prevent the start up noise, the floating pin clearance must be kept so tight that the pins are almost press fit again.

 

[bbobynski]

quote:

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Originally posted by buster:
bbobynski, what is your take on breaking in the engine hard in the first 20 miles? Thats been a controversial subject on most websites. Most manuals state to wait about 500 miles before going over 60mph and flooring it. Some have said flooring it as soon as you buy it is good for it.

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This is pretty much covered above...

From previous posts...you don't want sustained , very high RPM very early one as any debris in the oil off the (iron) cylinder walls will be in the oil before the filter. High RPM will cause the filter to bypass and send the unfiltered oil to the bearings feeding them the breaking debris off the cylinder walls. So...don't be afraid of the throttle but avoid high RPM for the first few (or maybe 25...???) miles and use a load/decel breakin as described above to load the engine and then alternate with moderate engine braking/overrun.

 

[bbobynski]

quote:

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Originally posted by moribundman:
bbobynski, this tidbit about the tinplate on new bearings is very interesting. So far nobody has ever mentioned that here.

Seems like you might be the man to tell me if lead-free bearings are actually being used in modern motors and if so, why do we see lead show up in essentially all UOAs? Federal Mogul keeps talking about producing lead-free bearings and at least some Euro carmakers claim to use them. What's up with that?

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I don't think anyone is using lead in bearings anymore. There is just too much liability in producing anything with lead in it whether the lead is "contained" or not. Just using lead exposes someone to it along the way so it is universally avoided. I think that all the bearings that I have had anything to do with since the late 90's have been lead free.

Bearing technology has changed tremendously over the last 15 years or so. Bearing shells used to be rolled to shape thru a set of offset rollers or mandrels. This restricted the shape of the bearing as to what the process could produce. Bearing shells are NOT round on the ID. There is a carefully developed shape or eccentricity to the bearing. Install a set of bearing shells into a rod or main and measure them with a mic. you can easily see the eccentricity in the bearing shape by the different diameters in the load vs. the split line direction. That shape is now turned or machined into the bearings. Formerly, the bearing material was rolled into shape as mentioned restricting the shape and the material that could be rolled. With the machined bearings, much harder aluminum bearings can be made as the bearing is rolled roughly to shape and then heat treated for the desireable material qualities. The shells are then clamped into an arbor and a CNC machining tool turns the final surface contour into the ID of the shell. You can have your initials turned into the surface if you would like as those CNC machining tools are very accurate and can cut any sort of contour. This allows much higher performance bearings with much more material properties as options and much higher performance contours in the eccentricity.

Possibly some of the bearings have the very fine tin overplate or a lead/tin overplate for breakin that causes the lead to show up in an oil sample when the engine is new...???

 

[moribundman]

bbobynski, thank you for all that information.