Motor oil

[copperjohn]

I need some input on oil for the old straight 8. Which company is reccomended as having the best quality engine oil with zink and which weight is better for mostly summer driving.

[The Old Guy]

You will probably get 20-30 different opinions !!! I run 15-40 Rotella in my 40, or 10-40 Valvoline and have driven it over 100 K

[Barney Eaton]

I don't have an opinion......but I did look up some information. (revised after finding newer info)

When it comes to this zinc thing, it appears the oil industry refers to it as Phosphorus (the zinc is built into it)

(zincdithiophosphate also spelled zinc dithiophosphate or zinc dialkyldithiophosphate - abbreviated ZDDT

Along these lines, I found that WalMart carries their own brand "SuperTech" Universal

my store only has 15w-40 and only in 1 gallon containers, they may have other viscosities in other parts of the country.

The SuperTech Universal has the following API ratings, CI-4, CH-4, CG-4, CF-4, CF/SL, SJ

From the information at the link below on ratings, there seems to be overlap in the ratings.

The newest is CI-4 (2004) and it has .5 ZDDT, CH-4, CG-4 also have the same amount of ZDDT.

Just found this up-to-date listing of API ratings

http://www.aa1car.com/library/API_ratings.pdf

Type in "motor oil service ratings" and search the web to get lots of information.

Edited October 28, 2010 by Barney Eaton (see edit history)

[FLYER15015]

Copperjohn,

Having just aquired a 1940 BUICK LTD, I am going to do to it what I've done with the rest of the "fleet.

1. 1995 Lincoln town car 196,000 mi

2. 2002 Dodge minivan 186,000mi

3. 2002 Dodge 3500 stretchvan 164,000mi

4.1998 Ford explorer 202,00 mi

I use Quakerstate 10w40 and a can of "restore" every oil change, which is @ 5k miles. I change filter everyother time.

You will get 100's of opinions regarding "oil" cause it is like talking "religion" to some folks.

My opinion is the result of living next door to a retired Shell research chemist, and the insights he has provided as to his career developing oils and additives.

But this is only my opinion.

Best Regards,

Mike in Colorado

BCA #45728

[buick4547]

Copperjohn,

Having just aquired a 1940 BUICK LTD, I am going to do to it what I've done with the rest of the "fleet.

1. 1995 Lincoln town car 196,000 mi

2. 2002 Dodge minivan 186,000mi

3. 2002 Dodge 3500 stretchvan 164,000mi

4.1998 Ford explorer 202,00 mi

I use Quakerstate 10w40 and a can of "restore" every oil change, which is @ 5k miles. I change filter everyother time.

You will get 100's of opinions regarding "oil" cause it is like talking "religion" to some folks.

My opinion is the result of living next door to a retired Shell research chemist, and the insights he has provided as to his career developing oils and additives.

But this is only my opinion.

Best Regards,

Mike in Colorado

BCA #45728

+

Geesh, I hope this doesn't lead to a religious discussion, but I use a good non-detergent 30 weight oil in my original '39 engine. Have for years, and no problems. I just don't want to "clean" that old engine too much. Might lead to bigger problems. That's my opinion and I'm sticking to it.

[Guest Roger_Roy]

you might have to rethink I hear oil companies have been changing the content of their oils to comply with pollution requirements (some of it gets burned even in a new engine) the thing to look for is

1,500 ppm Zinc (Zn) and 1340-1400 ppm Phosphorus (P)

or close to it, what you were using years ago may not today be the same oil. You really have to read the small print, it seems almost no oils have the amount of ZDDP older engines need , not even the diesel oil I used to use. One of the valvoline ones do, this is from the Penrite site:

Zinc Dialkyl DithioPhosphate, also referred to as ZDDP or the "zinc" in an oil, is a chemical compound which is a very effective anti-wear agent. For this reason, when ZDDP levels were lowered in oils to meet the latest specifications in some new vehicles, it caused worldwide panic, as older vehicles manufactured pre-2006 needed the high levels of zinc (especially preferred and required by pre-1970s vehicle owners). For futher details on ZDDP and oils in the Penrite range which have lower zinc levels ( Enviro+ range), please refer to Technical Bulletins 85,128,129,137 and 149.

so what was good before now may not be....

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[Mark Shaw]

Check out this site....

Welcome

[Pat_n_Pat]

Here is another site that adds to the technical aspects. Although it focuses on Corvairs, it applies to all internal combustion engines:

http://www.widman.biz/uploads/Corvair_oil.pdf

I have had a few e-mail "conversations" with this guy. Quite helpful!

Pat

[Guest agriffey]

Just because you drove your roller tappet 2001 Rollscanhardly 436,000 miles with no engine problems does not mean you can use that same oil in a flat tappet car and get the same results.

Now we may not need all that ZDDP in our early flat tappet low valve spring pressure engines but then I just play it safe and get the Accel oil at WALMART for 2.38 a qt. It comes in 10-40 and is for cars '88 and older(flat tappet) and is SF rated, which means it is the older formula which has pleanty of ZDDP.

Spending any more money on oil is a total waste of money.

Those oils all meet the same specs. This is not the forties anymore.

I liked Castrol and Valvoline too, but now I would not spend the extra money to buy either brand.

The cars we are conserned with here were suposed to use SAE 20 in warmer weather. 10-40 is plenty heavy, maybe too heavy.

[Mark Shaw]

I agree with agriffy....

I buy the cheap stuff for all my older Buicks because any modern oil is much better than the stuff from the teens and 20s....

I also use Shell Dentax or Texaco Thuban SAE 250 in my transmissions and rear ends. These heavy lubes make shifting much quicker and easier while providing superior lubrication.

[Guest Grant Magrath]

I need some input on oil for the old straight 8. Which company is reccomended as having the best quality engine oil with zink and which weight is better for mostly summer driving.

There was a discussion a while back where it was agreed that if you had an old engine, oil with a detergent in it could cause sludge to disperse, possibly blocking oil galleries, but with a freshly rebuilt engine, it wasn't an issue.

Cheers

Grant

[Guest agriffey]

It's not an issue with an old engine either.

The detergent oil will not loosen all that sludge and plug the oil passages.

If it did loosen the sludge all that oil pressure would push it right through the oil galleries.

You can not go wrong with 10-40 or 10-30 in a used engine. Straight 20 is what was called for 'in those days'. Although I would run 10-40 Accel from Walmart because it has plenty of ZDDP, even though we may not need itin cars with low tension valve springs.

For break-in you can add a bottle of cam break-in to any modern oil to get the ZDDP and after that just use your favorite oil. My favorite oil is whatever is on sale or cheaper than the next.

It all has to meet certain specs.

If I could get 5-30 with plenty of ZDDP I would use that, but there is none so I'd go to the Accel 10-40 or any other oil for SF or SJ rating like motorcycle oil.

If you think 10-40 is too light for your engine then you can go to roofing tar or Penrite 20-50 for old cars..

I've seen cars that had been run 40 years with non-detergent and then switched to detergent because there was so much crud in the oilpan that it would only hold half as much oil as it was supposed to.

The owner ran high detergent oil and changed every 500 or 600 miles for several years and it never loosened any of the sludge. We had to pull the pan and scrape it out.

I've seen that happen too many times. That idea of detergent oil loosening every thing is an old wive's tale. And speeking of old wives and tales....never mind.

[Guest Grant Magrath]

:)Ha ha!

Well that's that sorted then!

Cheers

Grant

[W_Higgins]

The SAE paper on this subject is the best source of information. Beware what you find on the web. They were studying it over 30 years ago, whereas it's only been a topic in the old car community for the last few years.

My understanding is that this is mostly a problem with newly rebuilt flat tappet engines. In broken-in engines where the the lifter is already riding on a large contact area, it's not really an issue. Also, we'd see every flat tappet engine dropping out left-and-right if that were the case.

There's no harm in adding a ZDDP additive so long as it's in the proper quantity (you can have too much, too), it's just that I think much of this is overblown in an effort to sell more additives, and quite often these articles we read on the web come from sites where they're selling a remedy.

Also, don't forget that inferior metallurgy in reproduction cams and lifters is to blame for some of these failures we read about.