oil?

[dnguyen1963]

its nonsense b/c newer cats are cheaper and crappier...and teh U.S. govt made a law or something to force the warranty that all NEW cats are garunteed to last 120k or something...don't quote me on specifics, but thats what i read...somewhere, sometime..maybe in the deep web...the car manufactures and oil companies just came together to help each other out...and possibly the new metals in engines don't need zinc...i didn't read that last part, but its plausible.

Do you understand anything when I said zinc complexing with palladium/rhodium?

[nando]

as far as I know there has never been any real evidence that ZDDP damaged cats (at least not in the concentrations that older high zinc oils had). it's was "suspected", not proven.

if you're burning so much oil as to coat the cats enough to damage them your emissions are probably fucked anyway. right?

[dnguyen1963]

as far as I know there has never been any real evidence that ZDDP damaged cats (at least not in the concentrations that older high zinc oils had). it's was "suspected", not proven.

if you're burning so much oil as to coat the cats enough to damage them your emissions are probably fucked anyway. right?

The tests are quite simple. Elemental analysis for zinc and oxidation test for palladium.

[nando]

but in what concentration? in a lab setting?

where's the real world evidence? my original M20 cat had 220,000 miles on it and was perfectly functional. The M20 had high ZDDP oil in it that entire time.

Mobil ran their test M20B25 to 1,000,000 miles with a high zinc oil. Yeah, it was a "lab", but surely if ZDDP = death to cats they'd have to replace it a couple times in 1,000,000 dyno miles?

[dnguyen1963]

but in what concentration? in a lab setting?

where's the real world evidence? my original M20 cat had 220,000 miles on it and was perfectly functional. The M20 had high ZDDP oil in it that entire time.

Mobil ran their test M20B25 to 1,000,000 miles with a high zinc oil. Yeah, it was a "lab", but surely if ZDDP = death to cats they'd have to replace it a couple times in 1,000,000 dyno miles?

Like I said, perfectly tuned cars will not experience this problem and I am sure your car and the one that Mobil tested are in excellent condition. The ones that are not well maintained and burning oil with high ZPPD (i.e. those that cannot pass CA emission) will most likely accelerate the death of their cat. As for real world evidence, this is similar to the battle for global warming...it depends on who you ask. My answer is based solely on the chemistry between zinc and precious metals in the cat. I have done many syntheses with palladium, and trust me, it does not take much to poison the palladium and render it ineffective.

[TobyB]

If your car is burning oil with high level of ZPPD then your cat will be destroyed in no time

THAT is nonsense. 'Complexing' is also not a chemical nor metallic term.

ZDDP DOES eventually chemically bond to the elements in NEW, MODERN 3 way cats and
render them less effective. And it's a warranty issue- since oil's changed every 20k now
engines DO wear more before the emission warranty's up, and there were statistical
problems running high ZDDP levels in modern motors...

THAT DON'T NEED IT!!!

Here's the thing, and here's where you're RIGHT- if you have a roller camshaft, ZDDP
is not needed. It's really only there for sliding friction reduction on the cams of
older motors.

So if you have an E30, run Mobil1 15-50, Brad Penn, or something else without a starburst
on it.
Your cat will last 50,000 miles or more, as designed, and may actually have 9 lives
and hack up a hairball...

If you have a more modern car that's been designed for low ZDDP oils, by all means run
them. Hell, even my 89 mitsu has roller rockers. The M20's ancient.

And needs ancient oil...

t

[Komzorz]

I can tell you what oil I wouldn't recommend - Castrol Edge 5w-50.

It's a great oil, but leaks like a sieve out of my 80k mile m20. I'm guessing it's just too slick for our simpler needs. Will be switching to Brad Penn.

[stamar]

I can tell you what oil I wouldn't recommend - Castrol Edge 5w-50.

It's a great oil, but leaks like a sieve out of my 80k mile m20. I'm guessing it's just too slick for our simpler needs. Will be switching to Brad Penn.

I have no leaks with napa brand synthetic 5-50 which is made by valvoline

but I have noo data on the zinc content.

[dnguyen1963]

[quote=TobyB;3316793]THAT is nonsense. 'Complexing' is also not a chemical nor metallic term.

Go back and read your Chem 101 text book if you do not understand the term "complexing".