Raced 94 Corvette LT1-RedLine 20w-50 2400 miles

[sidney004]

Car has 80,400 hard driven miles.It is taken to road race events, this sample represents 13 hours of track use(4200 RPM to 6000RPM at 280F+) The data(which represents 8 years) is listed from newest sample on the left to progressively older data. First data set(RL 20W-50),Second data set(RL 10W-40),Third data set(RL 10W-40)Fourth data set(RL 10w-40),Fifth data set(RL 10w40),Sixth data set (RL 10w-40),Seventh data set (RL 10w-30), Eighth data set(Amsoil 10w-30 + red bottle Valvoline Synpower), Ninth data set(Amsoil 5w-30); Most recent analysis used an Amsoil EAO23. Data sets four thru nine performed by Analytics Inc, Data set one, two and three were performed by Oil Analysers. 3 quarts of RL 20W-50 were added during the 2400 mile change interval.
Oil Analysers flagged the oxidation as severely high and nitration as moderately high, but Dave at Redline says these are normal readings for ester based oils and to ignore it. They also flagged the Nickel as being at a significant level. I routinely use MMO in the gas. I switched to Redline 20W-50 from the last analysis.
FE 26....29.…..24.....26.....33.....30.……..49..….36.....94
CR 1.....2.…...1....…2......3....…2..……...2....…..2......5
NI 11....9.…….4......2......3......2...……….5...…...7.....18
AL 8.....9.…….8.....16.....6.....9...……….13..…..9......34
PB 31....38.…..22.....25....35...25..………58...….39.....111
CU 6.....9.……6......8......8......7...……….7...…..7......15
SN 2.....7.……7......23.....23.....6...……..15...…..6......21
SI 22....24.…..28.....45.....81.....34..…….18..…..16.....30
B 16....11.……12.....23.....41.....20..…….28...…136.....3
NA 25....29.…20.....37.....33.....32..……...37...…16.....28
K 5......0.…..4...... MO 798...824...821....965....908...726.……695....…231....11
P 1280...1164...1086....1056..1145..1049.….1303...1348...1309
ZN 1336...1377..1323...1509...1564...1170...1803...1589...1968
CA 2963...2828..2734...3417...3502...2633...3605...2796...3554
MG 14....13.…..13.....28...….30.…...27.…...254....837....427
Mil 2400...2800...3000...2200...2000...3800...3000...3100..6000
Fuel T/S% H20 VIS 20.7..15.4 15.0 14.5. 14.3.. .16.3...12.1.. .13.5. ..12.8
TBN 5.44...4.24..4.82
OXI 102...85..72
NIT 23...24...23
By the way, I "recycled the oil" I'm putting the used oil thru my Saturn when it needs oil added(which is often!)

 

[Turk]

"3 quarts of RL 20W-50 were added during the 2400 mile change interval."

Wow, does it burn that much oil or leak it?

 

[sidney004]

Mostly burns it, it consumes almost a 1/2 quart per track event; it leaks a little as well.

 

[jaj]

Engine looks happy running on any one of these oils.

 

[sidney004]

The epilogue; at a little over 83,000 miles at Thunderhill raceway, the old warrior massively overheated. Subsequent teardown indicates that the failure was that the sprocket gear teeth(I think they're powder metallurgy)which drive the water pump stripped off, spewing metal throughout the engine. So in the end, the UOA didn't foretell this failure mode but the engine proved very reliable and provided fantastic service given the amount of track time it had; I'd estimate over 150 track hours.

 

[A_Harman]

Interesting history of oils and UOA's. Sorry to hear about the cam sprocket/water pump gear failure. Are you rebuilding it? I have a modified L98 in my Corvette that I have been tracking for many years. I ran it last season on RL 5w30 and just drained it for a UOA.

I also get about 1/2-quart oil consumption per track day.

Iron readings were mostly pretty good except on the AMSoil 5w30.
Lead readings were pretty scary all the way through. What kind of oil system did the engine have?
What do you think was the source of nickel?

 

[AndrewD]

280+ is pretty high, any chance an oil cooler could help bring that down?

 

[A_Harman]

280F is a pretty safe limit. I wouldn't worry about RedLine oil until the temperature gets over 300F.

 

[jayg]

Originally Posted By: AndrewD
280+ is pretty high, any chance an oil cooler could help bring that down?


280*F isn't that high on the track. I wouldn't worry about it.

 

[jrustles]

inb4 "the 20w50 ruined your engine"

 

[jayg]

Originally Posted By: jrustles
inb4 "the 20w50 ruined your engine"

Hopefully those people would realize on an engine that is only used for racing and is at temp virtually always, that 50 wt oil isn't a problem.