Re: [Amc-list] motor oil confusion

[Frank Swygert <farna@xxxxxxx>]

The problem is that the government and auto manufacturers have pressured oil companies into removing most of the zinc (which is used as a high pressure resistant lube) from oil. The reason is an oil burner car will coat the inside of a catalytic converter with zinc and eventually render it useless. Manufacturers have to warrant cats for 100K miles, and of course the EPA (gov't) wants them to work. Since almost all auto engines are now roller lifter engines there's no real need for the high pressure lube. Apparently there's not as much pressure on OHC followers as push-rod lifters, as they don't seem to be affected. 

So far, as long as a flat tappet (standard lifter, no rollers) cam has been broken in with a high pressure additive in the oil, there's still enough zinc in regular oil to lube it -- at least in a STOCK engine. The people who've been experiencing problems the most are those with higher pressure valve springs (performance engines). There may be increased wear on stock engines, but the zinc reduction hasn't been in affect long enough to really tell. So far the only people I know with stock valve trains that have experienced any problems related to low zinc are those who have just rebuilt engines. A zinc supplement in the break-in oil seems to be the short term answer. I'm not sure if running a higher zinc oil is really necessary after break-in, but it shouldn't be. 

You were given correct answers. If using something like GM EOS for break-in, leave it in 500 miles or so and change it. You'd do that with regular oil on a freshly rebuilt engine though. You can use a lesser amount, say 1/4-1/2 the container, in the oil and run it. I don't think running something like EOS full strength would hurt a thing, would just be a bit expensive. 

Diesel oils generally have a bit higher concentration of zinc or other high pressure additives in them due to the high compression of a diesel engine. That's why some people have been switching to diesel rated oils. But you don't have to spend a lot of money to protect your car! Go to Wal-Mart and you'll find "Accell" brand oil that's still labeled API SF. That's an old rating! It specifically states "formulated for 88 and older cars" on the label. It should have higher zinc concentrations in it, but I haven't seen any test results. Current API rating is SM -- SL and earlier should have adequate zinc levels, so the SF should be great. It's under $2 a quart. 

As Tom mentioned, detergents in oil keeps dirt suspended so the filter picks it up. Since the 196 oil filtering system only filters 20% or so of the oil at any one time, 80% or so is holding dirt suspended in it to continue through the bearings. Sounds bad, but I drove a 196 powered car for 14 years and always used standard HD (high detergent) oil. At about 10 years (and over 140K miles) I rebuilt the engine. The bearings had what I would consider normal wear for a car of that vintage with that many miles. Some copper was showing, maybe 50-60%, which is pretty normal for that vintage/mileage. That car wasn't driven easy, and oil changes weren't always regular either -- and that was after I got it and took "reasonably" good care of it (most of the time...). So I wouldn't worry about the detergent content of the oil. 

If you have one with NO filter, only run ND (non-detergent) oil. Then when you shut it down any dirt will settle to the bottom of the pan and stay there. Every 20-30K miles remove the pan and scrape the goo out of it. That would be every other year with normal driving, but back then for most people it was probably every 3-4 years. Thats one reason all cars prior to the late 50s/early 60s had four point engine mounts -- the crossmember (if there was one) had to be easily removable so the oil pan could be removed without much fuss. 

My grandfather used to change the oil, strain it through some cheese cloth, let it sit in a covered bucket/can so any remaining crud would settle out, then use it for the next oil change! Typical model T maintenance, and those things would run a long time! He did that with the 8N tractor we still have for a long time, though that engine has been rebuilt at least once, I think twice (bought used in the late 50s, think it's a 52 model).

Oil never looses its lubricity, just gets dirty. The additive package diminishes and/or wears out though, and modern oils have viscosity modifiers and such that have to be there. A straight-weight oil hasn't got many additives and could be cleaned and reused though. In the 20s and 30s that's about all they had. 

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Date: Fri, 14 Mar 2008 11:20:38 -0700 (PDT)
From: Joe Smith <know_ware@xxxxxxxxx>

I am confused about the motor oil information.  When I read about the high ZDDP oils, they are either for diesel engines or they say to change at 500 miles, but the other forums I have read say leave it in for 3000 to 10000 miles!!

I have a OHV 196, so, what is best?  I just changed oil also.  Is there an additive that I can put in so that I don't waste this fresh oil?

Thanks!
Joe

-- 
Frank Swygert
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