the best motor oil for flat tappet cams?

[Impala0098]

recently I've heard from several of my mechanic friends that oils today don't contain enough zinc and phosphorous for flat tappet cams, one of them even showed me a pile of scuffed cam shafts.

I'm trying to find a decent motor oil with high zddp to run in my 58 impala any suggestions?

[1957Birdman]

Shell Rotella 15W-40 is what I run in my T-Bird. I've also run Pennzoil 15W-40 and have been fine so far. The key is to get oil that can be used in diesel engines. It has the extra zddp that is missing from regular motor oil these days. You can also get zddp as a stand-alone additive, but I don't think it is necessary if you use one of the aforementioned oils.

[straight shooter]

I second the Shell Rotella 15w-40 oil recommendation. It is also a high detergent oil that will keep your engines internal components clean.

[trainguy]

I use PENN BRAD in my flathead Fords.It is the only oil Isky recomends to be used with their cams.

[Impala0098]

thanks for the suggestion guys, I will consider running Rotella.

I was also thinking about trying this oil, it has a great zddp rating and comes in a 20-50 Fischer Brand | Classic Car Motor Oil | Products

[NTX5467]

I concur with the Rotella T 15W-40 OR Rotella 5W-40 synthetic. Rotella T 15W-40 was the oil which Comp Cams originally recommended for use with their cams, when the whole "decreased zddp" issue surfaced many years ago. Their complete recommendation was "Shell Rotella T 15W-40 or full synthetic motor oil". The Rotella 5W-40 covers both bases.

A plus for the Rotella T 15W-40 or 5W-40 is that they are readily available at WalMart and other similar places. NOW . . . there is a new Rotella T5 which is a blended synthetic that's not in the same viscosity range, plus a synthetic Rotella that's not 5W-40, so . . . be careful in that respect.

You can find "Virgin Oil Analysis" for the 15W-40 and 5W-40 in the - Bob is the Oil Guy website's forums area, where various people have had the oils analyized and posted the lab's results.

Just some thoughts,
NTX5467

[1937-44]

My concern with Rotella is my car calls for SAE 20 in the summer and I'm afraid it will be to thick. I should mention the car I'm referring to is a 1954 Buick Century. I'm thinking of just using a cam lube additive with each oil change. Any comments? Carl

[Dave@Moon]

recently I've heard from several of my mechanic friends that oils today don't contain enough zinc and phosphorous for flat tappet cams, one of them even showed me a pile of scuffed cam shafts.

Everyone has heard this from someone. It's like hearing that someone running for office in the U.S. is a socialist, or that Paul McCartney was killed in a car crash in 1966. You can believe it if you want to.

There are other opinions. The most learned opinions differ wildly from your mechanic's (except in the rare case where a new rebuild is being broken in). However most people don't listen to them, as is born out in almost every thread on every forum on this subject (including this one).

Here are 2 entries into the more learned opinions on this subject. First is this 2009 article from Old Cars Weekly: Death by Oil? | Old Cars Weekly.

The consensus of expert opinion by those regularly engaged in developing engine oils based on objective tests is that modern engine oils, including the most recent category, SM, will provide satisfactory lubrication for collector cars. These oils are more than adequate for the typical collector car owners who drive relatively few miles under unstressed conditions. If for some reason you are uncomfortable with this preponderance of professional opinion, then use a ZDDP oil additive or an oil with ZDDP already in it, listed at the end of this article.

Second is the original essay from Bob Olree cited in the Old Cars Weekly, attached below. Mr. Olree's qualifications for voicing his opinion on this are impeccable. There simply isn't a more experienced source of expertise on this subject.

==================

One final caution: Most people boost the ZDP content of the oil in their collector cars using additives. This is especially the case for collectors whose cars (like mine) require an oil not available any more in elevated ZDP levels (in my case 20W50). This must be done VERY carefully! Too much ZDP is worse than not enough by anyone's estimate, causing metallurgical damage to wear points, especially tappets and cams. This results in spalling (the chipping off of flakes of metal).

[ted sweet]

the oil from 2007 is nothing like todays oil

[Dave@Moon]

the oil from 2007 is nothing like todays oil

Actually it is. The API SM oil rating, with a standard of less than 600 ppm ZDP, was introduced in 2004 for the 2005 model year cars. The current SN rating, introduced last year, did not change that specification.

[real61ss]

Anyone ever used Amsol? I haven't, just wondering what the opinions were.

[ted sweet]

all i know is my cam manufacture wont let me run any sm or sn oil.

[NTX5467]

I was thinking the design spec for "SM" oil was more like 800ppm zddp? I don't recall seeing any lab reports with 600ppm, UNLESS . . . there is something else, like liquid titanium, in the additive package, too.

Allegedly, the last oil to have approx 1000ppm of zddp was the "SL" rating oils, which is why many recommendations are to NOT use the later "SM" or "SN" oils. Most of the synthetics which have a VW or european mfg "approval" have 1000ppm of zddp, in the 5W-40 viscosity product.

The exception to the "No SM or SN" oil is the oils, like Rotella, whose original and "design" application is "diesel" engines. Although the current Rotella T oils are co-rated for "SM" applications, they still have well past 1000ppm of zddp in them. Check the - Bob is the Oil Guy website's forums for the "Virgin Oil Analysis", over the 50+ pages of lab report postings for the diesel motor oils and you can see their reasonably consistent zddp levels. Similarly, you can look at the 50+ pages of gasoline engine lab report postings and see how the zddp level has dropped as the oil ratings have progressed from "SL" forward.

As for "SN", it IS the latest spec, but the bulk of what I've seen at WalMart in "SN" is synthetics . . . which might change as more GM vehicles (worldwide) which need Dexos 1 hit the roadways. The GM Dexos 1 spec oil, in the ACDelco brand, is a blended synthetic, not a full synthetic.

As for the Summer spec for the '54 Buick being 20 oil, Many of the 10W-30 oils "shear" down to close to the "20" viscosity with time. Also, when that car was built, there were NO multi-viscosity oils available. One of the noted '55 Buick restorers, who's in the BCA Forums as "Old-Tank" uses 20W-50 Castrol GTX in his '55 Buicks, and has for some time. Not sure what's happened lately, though, since the zddp levels have flaked on us.

ALSO . . . remember that zddp is only ONE of many anti-wear additives which can be in motor oil!!! But it is one of the less expensive ones that works well, which is most probably why it was chosen in the first place.

One of the things which I don't like about the (posted) old car motor oil is that its TBN is quite weak compared to other oils on the market, especially the diesel-original-application oils, as Rotella. That means that it'll turn "acid" in ph level much sooner, but it should be good for about 4000 miles anyway, I suspect. But then I just like to use a name brand oil that I can buy readily OR have ready access to in the oil change industry.

Just some thoughts,
NTX5467

[caddyshack]

Who remembers the "STP" Oil Treatment?
Directions called for a 10% mixture when you changed oil. Could even be used in Manual Transmissions and differentials. Growing up with 60's era cars, everybody was using STP in their engines. I have used it in A's, T's, early Vettes etc. with no problems. I have three 15 oz. cans (old paper cans) left from the two cases I bought in the early 70's. There are no specs on the can. Anybody know what this stuff is made of?
Thanks

[Terry Bond]

I've followed all the discussions on this topic for a couple of years now. Felt it was important when we were putting our newly restored MGB on the road, and we like to drive it a lot. Consensus among the British car crowd was that the Rotella was ok but lately that has shifted to Valvoline racing oil. We ran Rotella for a while but I went with the flow (no pun intended) and switched off to Valvoline racing oil like many others. We've got over 20K on the car now and not a problem.
Terry

[dep5]

The Indiana Region of the Classic Car Club of America and D-A Lubricant Company, Inc. are proud to present a revolutionary new motor oil specifically produced to reduce mechanical wear in your classic car's engine.

http://www.classiccarmotoroil.com/

[Dave@Moon]

I was thinking the design spec for "DM" oil was more like 800ppm zddp? I don't recall seeing any lab reports with 600ppm, UNLESS . . . there is something else, like liquid titanium, in the additive package, too.

As I understand it, 600 ppm is the current minimum spec., 800 ppm is the maximum.

[1937-44]

Thanks NTX5467 for your comments about oil weight on the 54. I started out using 5W20 although the engine was quiet the pressure just didn't seem quite high enough after it warmed up. I switched to 10W30 this summer which makes me feel better when I look at the pressure gauge although it pegs on the high side until the engine warms up. Just been a little leery to switch to 15W40.
Appreciate all the information and opinions everybody on the ZDDP issue it helps some of us decide our own course of action. Carl

[Ron Green]

One of the most opinionated subjects in the old car hobby so here’s mine. For many years; I have beat the snot out of my 72 Corvette, run the 55 Pontiac at 70MPH on expressways and have even run the Amphicar with lots of water in the crankcase (another story) at 60 MPH for 20 minutes with zero issues using Mobil 1 synthetic oil.

All carbureted vehicles will put a certain amount of gas into the oil and synthetic can handle this better than conventional oil including the acids, plus they take the heat and cold better than conventional oils. Take a valve cover off a vehicle that has used conventional oil and see the brown residue as they don’t refine many of the conventional oils as well as synthetics. Take a valve cover off an engine that has used synthetic oil for its life and they are typically squeaky clean.

I buy 6 quarts at Wal-Mart for $27 so it is a bit more expensive. They solved leaking seals with synthetic oil decades ago. Mobil 1 phosphorus levels range from 800 to 1200. Zinc levels range from 750 to 1300. Both levels are more than adequate.

From the Mobil 1; http://www.mobiloil.com/USA-English/...duct_Guide.pdf

[NTX5467]

Ron, thanks for posting that Mobil 1 chart! Sometimes, it can be hard to find on their website. Lots of good information in it, too!

Thanks,
NTX5467

[mercman86]

Valvoline VR-1 Racing oil. Like others have stated, the 15-40 is too thick for some applications. The oil we use at work has tons of zddp added into it but its 25w-40 marine oil. Way too thick for my little 200 in the ranchero. 10w-30 VR-1 is what I use with no worries at all.