ZDDP

[Mick Lynch]

I’d be interested to find out the ZDDP parts per million values of oil from the 1950s.

I plan on using Shell Rotella T1 30 monograde (which has a ZDDP value of 917 PPM) and using Lucas TB Zinc Plus ZDDP additive which has mixing ratios of +500 to +5000 PPM on the bottle.

I can’t get a definitive answer as to what the average ZDDP value should be. Worryingly I also found the statement ‘too much ZDDP is worse than not enough’ on a website.

So does anyone know what the ZDDP values would be in oils of the 50s to now?

[JOWETTJAVELIN]

No idea, but the 'classic' oils available now contain it in varying quantities.

[nutmegct]

From the Rock Auto website:

"The anti-wear benefits of ZDDP were recognized in the 1950s. The oil of the 1950s had only about 300 parts per million (ppm) ZDDP. The concentration of ZDDP in motor oil gradually increased until it reached a maximum of 1200 to 1400 ppm in the 1980s. (More than 1400 ppm of ZDDP in oil actually starts to increase engine wear.)"

[moggiethouable]

This blatant sales pitch from Duckhams may help.
I use Castrol and have never considered ZDDP.
https://www.duckhams.com/zddp-what-does-it-all-mean/
My first thought was "Snake oil"
But then I am just an old curmudgeonly cynic.

[panky]

I use Valvoline VR1 in my Mini as recommended by those in the know on the Mini Forum. High ZDDP content helps the gearbox cope being bathed in the same oil as the engine.

[liammonty]

I'm intrigued that you are using a monograde oil, assuming it's going in an A-Series engined Minor? I'd be more keen to use a decent mutigrade rather than too concerned about levels of ZDDP - BL recommended multigrades when they became available as they are better than the monogrades that came before them. I've got an aircooled VW as well as the Minors (and other cars) and many still advocate using monograde oil for them, but VW themselves were recommending multigrade oil from the 1970s.

I've been using a 20W50 multigrade from here: https://www.classic-oils.net/

It's endorsed by Fuzz Townsend and has a high ZDDP content, so could be a good alternative to a monograde?

[Mick Lynch]

I'm intrigued that you are using a monograde oil, assuming it's going in an A-Series engined Minor?

I’m a cheapskate trying to make my own ‘break in’ or ‘running in’ oil for a 918cc sidevalve I’m rebuilding.

From what I have gleaned 1400 ppm is optimum for the little saloon engine and SAE30 is the optimum oil for it although I suppose it could use a multi grade, which may help winter starting (but it won’t be going out in the cold!)

Interesting to find out that racing engines and ‘drag/hot rod’ engines recommend up to 3000 ppm

[liammonty]

Ahh - fair enough! It sounds as though your running in oil will be as good as normal oil though, which perhaps defeats the object?! Are you aiming to protect the cam with the high ZDDP concentration while running in?