There's a clue if you read the urban legend. It's where in claim about the
big three using roller lifters in all their engines. For the big three do
NOT use roller lifters. Never have, and probably never will.
So where would that claim about roller lifters come from. Ah! There's a
lead to the truth.
It's from high performance circle track racing engines, using radical lift
cams with fast ramps, and .... (drum roll please), roller lifters!
Keep following the story, and you can even arrive at the original racing
team that finally figured out what was causing their camshafts to be failing
suddenly, some years ago. I think the team was Roush, but I don't remember
with certainty.
None the less, this urban legend will continue without interuption, right
along side the need for backpressure, overheating from water going through
radiators to rapidly, US Spitfires having lower front ends, centrifugal
force, and several other falsehoods.
----- Original Message -----
From: "Randall" <tr3driver@ca.rr.com>
Cc: <shop-talk@autox.team.net>
Sent: Wednesday, October 22, 2008 4:58 PM
Subject: Re: [Shop-talk] Oil grade selection
>> There has
>> been much talk in classic car circles about this,
>
> Indeed there has been a LOT of talk, but precious little hard evidence.
> Just once, it would be nice for someone to assemble two identical engines
> and demonstrate the difference of running a low-ZDDP oil in one, and
> high-ZDDP in the other. The entire ZDDP debate seems to be based mostly
> on
> increased camshaft failures; but the increase in camshaft failures started
> BEFORE the reduction in ZDDP!
>
> BTW, ZDDP comes into play when there is metal-to-metal contact, ie the oil
> film breaks down. If full synthetics do have higher film strength, they
> should be better able to maintain the microscopic oil film and hence have
> less need of ZDDP.
>
> Randall
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