Selection of the Right Motor Oil for Flat Tappet Engines

[HawgRyder]

We used to use Castrol 20/50 in the racing VW engines...with Wynn's Friction Proofing in the oil.
BUT...we needed to run in the rings before adding the Wynns!
We found that if added too early...the rings would not seat.
So...I guess what I am saying is that the stuff worked...it reduced friction...but the engines got torn down more than 2 or 3 times during the season.
For what it's worth.
Bob

[RWebb]

barndoor - when you drive back from PDX, drop off a vat or so of the Brad Penn here in Eugene

[hbueno]

Good information, but I still feel like whatever oil I choose will always be inadequate in some way. For example, there's talk about catalytic converters, which BTW have been installed on US cars since 1974. What level of zddp is appropriate for a late 70's 911 if you need to take the catalytic converter into account?

The paper says CI-4 oils are best, those are intended for diesel engines right? What about something like Valvoline All Fleet Plus? It seems to have the right amounts of zddp but the MSDS I found says something about paraffinated something or other. Does that mean it's a "bad" Group I oil?

I'm so confused.......

Hugo

[RWebb]

true - whatever oil you choose will always be inadequate in some way; I suggest rebuilding your SC and later engines every 300,000 miles even if they do not need it

[richardlw]

Originally Posted by hbueno

Good information, but I still feel like whatever oil I choose will always be inadequate in some way. For example, there's talk about catalytic converters, which BTW have been installed on US cars since 1974. What level of zddp is appropriate for a late 70's 911 if you need to take the catalytic converter into account?

The paper says CI-4 oils are best, those are intended for diesel engines right? What about something like Valvoline All Fleet Plus? It seems to have the right amounts of zddp but the MSDS I found says something about paraffinated something or other. Does that mean it's a "bad" Group I oil?

I'm so confused.......

Hugo

Yes, Catalytic converters have been on cars to some extent for a lot of years, but I believe (this I can't say for sure) they were less efficient and less sensitive.

What I can tell you is that I use CI-4 Synthetic in my 88 BMW and so far the converter is not blocked. I have no way of measuring if it is effective, but since I use 28% leaded av gas in it, I doubt it. (gasoline here is 80 octane, although every couple of months one gas station brings in a load of 90)

The problem with the phosphorous comes not merely from the level, but what they learned after the SM fiasco was that some phos compounds evaporate more readily. So the SN oils have to maintain 79% of their original value. The better CI-4's and CJ-4's are made with the better phos compounds, so you could have 10% evaporation of 1200 ppm in a CJ-4 and still have less contamination than the 79% retention (21% evaporation) permitted in an SN with it's 800 ppm limit.

[A horse with no name]

Hi...For what it's worth - I use Mobil1 synthetic 15-50. If I drove the car during the winter I would likely go 10-40.

[HarryD]

Originally Posted by richardlw

Yes, Catalytic converters have been on cars to some extent for a lot of years, but I believe (this I can't say for sure) they were less efficient and less sensitive.

What I can tell you is that I use CI-4 Synthetic in my 88 BMW and so far the converter is not blocked. I have no way of measuring if it is effective, but since I use 28% leaded av gas in it, I doubt it. (gasoline here is 80 octane, although every couple of months one gas station brings in a load of 90)

The problem with the phosphorous comes not merely from the level, but what they learned after the SM fiasco was that some phos compounds evaporate more readily. So the SN oils have to maintain 79% of their original value. The better CI-4's and CJ-4's are made with the better phos compounds, so you could have 10% evaporation of 1200 ppm in a CJ-4 and still have less contamination than the 79% retention (21% evaporation) permitted in an SN with it's 800 ppm limit.

Richard:

School me. What is the "SM Fiasco"?

[Joe Bob]

Lead kills cats, you burn unleaded gas. Burning oil shouldn't be an issue, if you are burning enuff to clog a cat, that cat is the least of your worries.

[theQuicker1]

Are we still going with the same brands over a decade later? Have they been bought out or changed ownership or changed philosophies on quality? Maybe they decided to change their formulations to something cheaper to pay off some bills? Maybe regulations in the last decade have forced them to formulate oil differently. Has anyone checked this out recently?

[Bill Verburg]

Originally Posted by theQuicker1

Are we still going with the same brands over a decade later? Have they been bought out or changed ownership or changed philosophies on quality? Maybe they decided to change their formulations to something cheaper to pay off some bills? Maybe regulations in the last decade have forced them to formulate oil differently. Has anyone checked this out recently?

There have definitely been formulation changes in some oils over the last 10 yrs.

LN Engineering puts out an informative series of updates on this topic

here is the latest detailing changes in Brad Penn and VR1

LN is recommending the newest line of Driven oils, specifically Driven GP-1 20w-50 or 15w-40 for the aircooled cars

I see no change in M1 15w-50 and will continue to use it in my cars.

[A horse with no name]

‘Dido’...Mobil1 15-50 continues to work very well for our 3.2

[adias]

Originally Posted by theQuicker1

Are we still going with the same brands over a decade later? Have they been bought out or changed ownership or changed philosophies on quality? Maybe they decided to change their formulations to something cheaper to pay off some bills? Maybe regulations in the last decade have forced them to formulate oil differently. Has anyone checked this out recently?

I moved from Brad-Penn to Liqui Moly Touring High Tech 20w50 and could not be happier. Much lower oil consumption and smoother idle. I also add two 300mL cans of Liqui Moly MoS2 (molybdenum) to protect moving surfaces, including tappets; being a solid lubricant it adheres to the surface and protects cold starts.

[911pcars]

Protective zinc and phosphorous only apply to flat tappet engines, mostly vintage cars that don't have roller cam followers.

The short answer is to stick with the oils mostly recommended here.

As mentioned above, it's not as simple as buying oil w/zinc/phosphorous or adding it to regular oil as an additive. Manufacturers are on the band wagon touting their own Zinc/Phosphorous claims. However, only oil manufacturers can improve the quality of the base oil/additive package (i.e. customers cannot make chicken soup out of chicken ____).

The long answer is here. It's a little dated (2013) and manufacturers have had time to reformulate. It's a good read, but long, like the Mueller report. Also, good engine tech tips buried in the tome:

https://540ratblog.wordpress.com/
synthetic-oil-not-20w-50-a.html

Sherwood