"Critical" lead levels!

[dirtdaddy]

This is probably a heck of a first post, but I need opinions from someone with more oil (and racing engine) knowledge than I have.

Background...383 SBC drag race motor with aluminum heads, approximately 150 passes total, 50 +/- since the last oil change with Brad Penn 10w40 Racing Oil. I just got the results back from my UOA. The additive still look good, phos = 1440, zinc = 1627, moly = 18 and viscosity at 100c = 11.5. The wear metals concern me though. Iron = 341, Alum = 100, and Lead = 1,148, which is my biggest concern and was flagged as "critical" by the UOA lab (Schaeffer's). Is there any way to tell if this indicates excessive bearing wear or could it just be from the lead in the racing gas? I'm guessing the only way to tell about the bearing wear is by tearing it down and inspecting, which I am planning on doing this winter. Just wondering if anyone else out there has noticed high levels of lead in their UOA due to the lead in the fuel and also trying to decide if I should take a chance on running it for the last race of the year. Thanks for any input!

 

[Donald]

What is the copper? Also an indicator of bearing wear.

 

[spasm3]

Are you running leaded race fuel? That would explain the levels.

 

[dirtdaddy]

The copper was 24. Yes, we are running leaded race fuel.

 

[dave123]

what fuel?

 

[dirtdaddy]

Sunoco Standard 110 Octane (Leaded).

Also, the car is using a small amount of oil. I had to add almost 1 quart over the span of 50 runs. So I'm assuming that there is some fuel getting by the rings.

 

[dirtdaddy]

Can anyone comment on whether the copper is excessive at 24 and would that come from anything other than bearing wear?

Also, Tin is low at 1 ppm. Wouldn't that be higher if the bearings were wearing excessively?

 

[sunruh]

dirtdaddy,

imho, the lead is of NO concern.

how or why i can say this?

because i race a dirtbike (single 250cc).
and
i have used leaded fuel.

i have seen as high as 651 lead in my uoa.
2 show over 600, 4 over 400 and 9 uoa's over 300
yes i dont run my oil 5hrs of motor time.
so let's do a little math.
my 1 cylinder is smaller than any of your 8.
your 150 passes ((1/4 fast, 1/8+ cooldown) + drive back + warmup) is probably close to 2 miles total, each. call it 300miles even.
i run maybe 60 miles total in an enduro that i run a uoa test on.
you go 5 times farther with 8 times the cylinders and only produce 2x the lead.

your sunoco 110 is similar to the howell 002 i was using.

NO ISSUE!!!

steve

 

[Cujet]

Aircraft piston engines, operated on 100LL, leaded Avgas, have insane lead levels. Even on frequent oil changes, 2500++ PPM lead levels are normal. In fact, I've never seen lower levels on my Lycoming.

I say that you have no issues at all.

 

[sunruh]

i am very shocked that Schaeffers (big name in dirttrack racing) doesnt know how to read a uoa where leaded fuel is used.

 

[Shannow]

Is the fuel aluminized and ironed as well ?

 

[A_Harman]

Since copper is low, it's probably not a bearing problem.
But the aluminum and iron may be of concern.

Can you cut open the filter and look for bearing flakes to be sure?
Has the oil pressure changed over time? If bearings are losing their linings, that would show up as a decrease in oil pressure.

 

[sunruh]

the alum is probably pistons and very typical in this application.
i would be more concerned about the iron.

my guess is this all might be ring wear and ring land wear (depends on ring composistion of course)
or
piston pin/small rod end and piston pin socket.

its a drag race motor. run full out...rebuild.

 

[dirtdaddy]

Update:

Thank you for all of the replies to my question. Upon tearing the engine down, the bearings looked great. No other extreme wear was noticed. Some minor wear on the rings, ring lands and cylinder walls, but nothing more than would be expected in this application. Just needed a standard 'freshen-up'. Everything points to the leaded fuel as the source. I plan on doing a UOA a couple of times a season now just to establish some kind of a baseline now that the engine is fresh. Thanks again!