cseaman

Back story on the car - purchased 18 months ago with 7000 miles, bone stock. Immediately fixed the heads with WCCH and did a BTR 2 cam, Corsa CAI, gutted cats, and tune. The car sat for 7 months after the build until I came home from a deployment in June 2017.

Drove it like that until February 2018, and at 22k miles, I had 2" Kooks headers installed. Car now has 27k miles. Retuned at the same shop by the same guy.

I have run Mobil 1 10W/30 in the car since I've had it (re: comments.)



Do I need to stop driving the car? It runs fine...I mean, I've literally put 20k miles on the car in the last 11 months. I've read a few threads about high titanium, so I'm not super concerned about that. The sodium has me more concerned, because the exhaust valves are filled with it, right?

Thoughts? First LS motor, first Blackstone report, and trying not to freak out.

MTPZ06

You have WCCH heads...so no, you don't have sodium filled ex valves any longer. Even still, you'd have serious mechanical issues if an ex valve leaked its sodium fill into your motor. As for the Ti intakes, I think they would wear the bronze guides before they themselves start to wear. Pull a valve cover and inspect for worn guides of course, but hopefully you're not dealing with a Ti rod issue.

Why the 10W-30 oil, and not something a bit more viscous for cold starts?

Hib Halverson

While Blackstone is my choice for oil analysis labs, reading your report, it may just be that not all Blackstone's technicians know LS7s have titanium connecting rods.

A high level of Ti in the oil can only come from two places, the titanium intake valves or the titanium conn rods. Sadly, if your engine is becoming a major **** storm, it can come from both places.

The sodium is not coming from exhaust valves. It's coming from coolant.

With only 4000 miles on the oil and sodium at 240-ppm, the first thing I think you need to worry about is coolant getting into the oil. This can be caused by a failing head gasket or a cracked head.

As for the high Ti residue, I'm going to go way, way out on a limb here and say that I believe your problem is more likely the conn rods. Richard (WCCH) uses CHE manganese-bronze guides. Bronze is an alloy of copper and tin. As you can see from the Blackstone report, manganese, copper and tin–all components of a CHE guide–are all extremely low. I believe that if the Ti valve stems were wearing, the manganese-bronze guides would show wear as well and, based on the very low levels of those three metails, my opinion is there is little or no guide wear.

That said, if you want to diagnose the Ti wear, first, I'd get the heads off, take 'em back to Richard and have him measure the intake stems and the guide bores. If they're ok, then you likely have a problem with the sides of big ends of the Ti connecting rods. To verify that, the motor needs to come out and be torn down. If there is wear through the CrN coating on the rods, that cannot be repaired and rods with worn big ends will have to be replaced.

Lastly, you mentioned you recently came home from deployment.

Thanks for serving.

Hib Halverson

Are you sure you didn't mean "less viscous"? But, I digress...

Unless the engine "lives" in Alaska or some other really cold place, I think a 10W30 is a better choice than 5W30, especially if Mobil 1 is the brand choice because...M1 is not truly a "synthetic" oil. It uses a synthesized hydrocarbon base-stock. From a marketing perspective, it's a "synthetic" but from a chemistry perspective, it's a highly-refined petroleum-based product.

Amongst 5W30s, a better choice is Driven LS30, an mPAO-based "full" synthetic oil.

MTPZ06

Yes, you would be correct...”less”. That’s my automotive dyslexia in action...often do the same with oversteer/understeer, taller/shorter gears.

As for oil, my last fill was 0w-40 M1 euro spec. Decided to go back to my longtime standard...Amsoil. 5w-30 signature series in the car as of this Monday. Gibbs really is great stuff, but I personally feel Amsoil is the best. I still don’t feel 10w-30 is appropriate for a street driven C6Z, but understand your reasons for saying so as M1 is an inferior oil to Amsoil or Gibbs.

Hib Halverson

The reasons why I feel that, except for places that get really cold during Corvette use, a 10W30 is a good choice are 1) from 1995 to 2016 all I used in Corvette LT5s, LS6es and LS7s was an ester-based full synthetic 10W30 and 2) there are few, if any 0W40s or 5W30s, which are formulated with no viscosity index improvers. VI improvers are necessary to give them such a vis ranges. Problem with VI improvers is they have no lubrication qualities. The more VI improvers are in the oil, the less "oil" is in the oil.

That said, "MTPZO6" lives in Alaska. LS7 use in Alaska has a different set of engine oil requirements than does my LS7 which lives in southern California. He needs a 5W and maybe even a 0W, I do not.

That said, I've tested Red Line 10W30 in sustained temperature as low -20°F and given a battery which can still adequately pulse discharge at -20°, I had no problems starting the engine which I was using for the test.

Currently, I've been using either Driven 5W40 or 5W30 but, during a recent back-order situation with Driven LS30 (the 5W30) I switched one engine back to Red Line 10W30 and run the other on LS30.

I'm not sure what level of Vi improvers are in the two Driven oils, but Red Line 10W30 has no VI improvers because RL's ester base stock has a "natural" multi-viscosity property. In case anyone is wondering, Red Line's 5W30 has a very minimal level of VI improver to get from 10W to 5W.

Apocolipse

Stop driving when a rod goes through the block. Otherwise...enjoy.

lamboworld

I have to agree and that is one reason why I don't do Blackstone reports. I drive it until I can hear a problem and then figure it out. Otherwise, drive it and fix it if it breaks. It doesn't cost all that much to have a new short block built for these cars, so use good oil, and keep your car maintained and fix it when a problem presents itself.

MTPZ06

I live in the one other state that is not part of the continental US...Michael D is up in Alaska though.

80atez

Let's assume the oil grade choice is not the issue (which it isn't)...

I am more like your neighbor than your mechanic answering, so grain of salt please...

Check coolant, any oil? Any loss? Any smell at exhaust to suggest burning oil?

Why is there a ? in the report under "coolant"..

Are you using oil?

Is the oil creamy? This is a sign of water in oil. You could put dye in the coolant or the oil to check crosstalk.

If you have no reason at all other than the oil analysis to think something is wrong, then I doubt anything is wrong, and maybe the oil was what the report writer thought, Mobil Special..

I would think a change of heads would not effect the lower end (con rods) without some major issue of static timing or other issue that would seriously effect driveability..

I suspect it's a head gasket issue with reassembly or oil properties (mobil special). Next would be some sort of mech issue..

But what one issue could cause both of those metals to be high and nothing else, I think that is the question... the lab suggests the oil was not what you thought and that would satisfy both items (Na and Ti) and thus seems most likely..

did you actually change the oil and add the M1 yourself?

If none of this could be the case, then and only then would I crack my motor open.

JesC6Z

Dan_the_C5_Man

The Ti isn't coming from the intake valves (extremely unlikely) - it is either the rods or possibly Ti spring retainers (check your build docs, see what was installed). Some oils also use Ti as an additive..

vertC6

I would be extremely concerned at that level, I would put 500 miles on it and test oil again if it's still high you need to take apart the motor and check the rods.