| similar story here . How could they just have made junk parts like this ? although someone like comp HAS to fix this . And I think they have , as you don’t hear of this like you used to . Zinc or not ….
The last time i used solids with the .016 oil hole in the face , after much back and forth in head . “ you are making a problem where there was none” might be true - we will see.
I don’t know enough about lubricants to comment on zinc levels etc , but if they are reduced from an optimum determined very carefully long ago by bright guys , pre catalyst, returning to somewhere near that seems to have no downside ? combined with consistent polymer length in the oil means predictable inherent oil performance , particularly over a temp . range .
Another thing is weight . … people who do not understand it equate high pressure as “good ” but what it really tells you is that restricted flow is happening inside the small places in the block . Like lifters and rod bearings , as the pump output volume is always constant per turn. Thick oil raises pressure because it is hard to push it through small places . Is that “ good?”
I learned this info two ways , twice by rebuilding Y block Fords over a 5 psi idle pressure , only to have 5 -6 psi after a perfect rebuild , and found nothing wrong inside either , They have a small oil pump ..
A well known old timer in rebuild business in Syracuse NY I used back then simply commented “ they all do that “
Yet despite other issues they have a reputation for bulletproof bottom end reliability like a slant six . .Slant six is on this edge too . All 55-57 fords the red light flickers at hot idlle , which disturbed me a great deal at the time ( 17-18 yo) in my first car .
But the second part of learning in this area really confirmed all this . I did not realize till l read an SAE paper on hydrodynamic oil pressure in the rod bearing space that the pressure in there caused by the wave of oil it slides on (acts like a surfer) is of the order of 3000 psi or more . ( i forget exact numbers ) because the rod DOES push down that hard on about an inch or two of bearing area . It is the traveling wave trapped in there that lifts it away .
So if you think about it , all the gauge pressure is doing is getting the oil to that space . Whether 5 or 60 psi at oil feed hole is lost in 3000 , obviously, at least for street engines .Also why “splash lube “ oiling worked in millions of Chevy sixes until 1954 . Like many others I simplistically thought the gauge pressure was lifting the rod by making the space full of oil ( EE should stay out of ME) . But before this insight I had a hemi cuda with 480” and milodon external line oil pickup ,pump and dual oil filters . Listening to “experts “ who are not , i had straight 40 or 50 race oil in it . One day I started it and both oil filters exploded .
Max wedges when they first came out sheared oil pump drives over this too , owners blamed the hex drive ( it was later beefed up by heat treat etc) but running thick oil was in play too . As we get older you realize a group of very smart guys spent a lifetiime designing this stuff . They know far more than I ever will , and they settled on 10-30 and lately even thinner ( Toyota) . And it was not influenced by irrational opinion or vocal “ racers” endorsing a brand . Toyota engineering is fantastic , as irritating as that may be . 250k NO problems. Not my thing , but still …
Early hemi 331 had all these problems in development , circa 1950 , cam wipe etc . as it could rev higher with dual points etc . and dual valve springs , they added spring loads to support that. Heavy exhaust rocker . They had a hard time , but got there. I trust them , not “ stories” or anecdotes .
That said, opinions will soon become beliefs and that is ok too . But thinner or correct oil cleans out rings , lifters etc and cools , and will carry dirt to a good filter , — so the “designed in “ high flow “ is good . Don’t slow it down . Use the oil recommended , is take away .. And don’t worry about gauge pressure too much unless a change happens . It will drop when hot — further confirmation of all this .. Hopefully all this is behind us now . J
Sent from my iPhone On Jun 23, 2023, at 11:25 PM, James Douglas <jdd@xxxxxxxxxx> wrote:
John, I know one engine builder in particular that did a not oh HP British sports car engines. He had several engines eat themselves. When he tore them down the same thing. Cams ground down by lifters.
He sent out the lifters and a few in every group they came back like HRC if 30.
After that he sent out every lifter he purchased, had them tested and send back the ones that fail out below 55.
James
From: John Grady <jkg@xxxxxxxxxxxxxxxxx>
Sent: Friday, June 23, 2023 13:38
To: dplotkin <dplotkin@xxxxxxxxxxxxxxxxxxx>
Cc: James Douglas <jdd@xxxxxxxxxx>; Chrysler 300 List Server (chrysler-300-club-international@xxxxxxxxxxxxxxxx) <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Subject: Re: {Chrysler 300} Motor Oil Zinc
my engine builder lost 7 race engines when the “ zinc thing” started . he had to eat them, huge $ from big racers . . they ( comp) blamed oil . I saw Ford coyotes there with . 700 lift . serious stuff .
he had tests done on comp hydraulic and solid lifters , they swore no changes. Flat out lies. He had old and new . Your could see different machining marks , he had them to show me— he had them tested , hardness and heat treat was totally
different — as well as appearance
He does hundreds of engines a year . They pushed roller cams “ due to zinc” ( coincidence ? -it was at the same time )
Now the real biggie ; he had in storage many 50 gallon drums of oil , years old , using the same oil all through this . Good stuff like Valvolline
He let them blabber on in emails , then threatened suit as oil was exactly the same , no failures for 15 years then 7 in one year .
They did a huge backtrack . Not sure how they settled , the usual “ admit no wrong “ here is cash .
He believes it was all bs , caused by chinese or mexican lifters and a comp corporate strategy to deal with ?suddenly hundreds of cam failures . Note it is not cam , it was lifters
all the millions of old darts and toyotas or chevy driving around with flat lifters did not suddenly start eating cams . But new engines did .
want the truth ? follow the $
ps i am sure this is fixed now , comp cam design is technically pretty good , although not all agree . But best cam in the world is turned to junk with bad lifters .
I became aware of the zinc controversy in roughly 2007 when I completed the build of my Ram Inducted 440 Savoy. At the time the machine shop Industry was facing inordinate camshaft failure. These failures were roughly coterminous with a
reduction in zinc in motor oil.
My understanding is that zinc is necessary in high performance flat tapit engines with heavy valve springs. Zinc is less necessary, maybe not at all in regular duty engines such as that in your DeSoto.
Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------
Date: 6/23/23 10:26 AM (GMT-05:00)
Subject: {Chrysler 300} Motor Oil Zinc
I am sure I will get a lot of grief but…
I use straight 30 or 40 without any zinc. The ZINC thing is in my opinion is much ado about nothing. Years ago, I talked with someone who does the testing of engine oils for a very
large organization. Their job is to evaluate the oil companies’ oil for conformance to their published specifications. They have a room of engines that are the most blueprinted and checked engines in the world. They must be to detect what oil does or does
not due to them. They are also all non-hydraulic cam engines.
They have found no wear differences with or without zinc in the engines. Period.
They have found that a number of camshafts in the 1990's, when a LOT of cam production moved out of the USA, had issues with Rockwell Hardness on the lobes. In fact, I know of several
engine builders that now send out camshafts and lifters for Rockwell testing. Guess what? Several of them fail even recently.
I suspect that proper hardness treating of cams and lifters drives much of the speculation about Zinc. I could not find one single "hard science" document on the subject. A lot
of opinion, but nothing definitive where two exactly the same engines in all respects were run with and without zinc and the wear differences were measured and documented..
My 1947 Desoto Suburban engine I built 20 years ago, has about 75K miles on it. I run it in the Hills of San Francisco and the Interstate to my place out of town at 70 MPH. The
car is about 5000 pounds. I looked at the cam a while back with the side covers off and a bore scope. The cam was NOS when it went in. It looks fine with no evidence of advanced wear. I never used any zinc.
James.
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