terahertz

yes, try amsoil. what oil are you using? as i said before, when i switched from mobil 1 to amsoil it went away, and when i switched back, it came back

2007 Zx-10

Right, but why would I have stuck valves at 10k when I've changed the oil religiously four times since new? Furthermore, everyone else seems to notice the same noise at start-up and it doesn't seem to be a wear issue, including the guy with 120k+ miles.

I'm running Amsoil 10w-30 now. I was previously running Mobil 1 EP and Synpower. I suppose I should time how long it takes for the noise to go away, it could be as little as 30 seconds.

2007 Zx-10

Maybe it takes awhile, I just switched over to Amsoil 10w-30 from Synpower.

INDYMAC

I think I'm done trying to help you. Good luck.

terahertz

are you using the 10w30 XL or the regular ATM oil? i used the regular non XL ATM oil and then actually switched to the 10w40 for track and have never heard it since switching to either

2007 Zx-10

You're not any authority on long term effects of using MMO. Again, I'd like to see back-to-back UOAs posted with at last 5k on each drain, and MMO consistently through that period.

2007 Zx-10

I'm running ATM. You're currently running 10w-40? Seems heavy for a high revving engine like this, but it might be ok in summer. Again, I think this is more of a nuisance noise issue, I doubt it corresponds to any significant wear. I just drive the car easy until it's warmed up, like most people.

INDYMAC

Well, even if you don't really deserve anymore of my advice, I'll offer this to the rest of the folks that might want to learn something about fuel additives and its effects on engine components in a gasoline engine:


Here is my latest UOA on a 2003 G35 with the VQ35DE engine.
Castrol Syntec 0W30 (GC gold) with no make up oil or additives.
OEM oil filter.
Microgard (Purolator) air filter (changed at the beginning of this OCI).
Total mileage 73,254.
OCI mileage 4190 (4.5 months).
Fuel used was Shell V-Power (93)
Fuel additive was MMO 4ozs/10 gallons on every tank.
Sample date 4/10/08

I will call this sample A, and compare it to sample B (previous fill of GC UOA with all the same vitals except for Chevron Supreme gas and Techron concentrate fuel system cleaners used for 4113 miles). The UOA's were both done by Dyson Analysis.

Element/A/B

Iron/9/9
Copper/3/12
Tin/0/0
Lead/15/21
Chromium/1/1
Nickel/1/1
Aluminum/3/2
Titanium/0/0
Silver/0/0
Calcium/1498/1634
Magnesium/457/381
Zinc/1090/1032
Phosphorus/1083/885
Barium/0/0
Molybdenum/1/9
Antimony/6/0
Silicon/23/17
Sodium/12/22
Boron/1/9
Potassium/0/0
Vanadium/0/0

V40C/71.4/72.3
V100C/11.6/12.2
TAN/4.42/2.60
Flash/285/320
Oxidation/13/14
Nitration/12/12
KF/399/521
TBN/5.2/2.1
Fuel/1.60/1.29
Soot/0/0
Glycol/0.31/0.83
V-index/159/168
Sulfate Byproduct/20/21

As you can see, fuel additives make a difference when it comes to leaching lead and copper from some bearings, especially if fuel dilution is prevelent throughout the OCI. I found similar data that validates this theory on another vehicle I own with fuel dilution issues, but it's not my S2000. It does not have fuel dilution issues. It's a shame because I prefer the way Chevron Supreme runs in all my vehicles, but I understand the consequences now.

If anyone else really wants to know some more info on quieting valvetrain noise, just PM me and I'll be glad to help you out the best I can.

2007 Zx-10

Lead and TBN aren't too hot considering the mileage. Furthermore, you need to compare them with zero solvents or cleaners added to the oil. Good bet the "fuel dilution" is actually solvent. I rest my case.