I’m now looking at what’s the best oil to run in my 850/950 Le Mans, as the new cam and followers are just going in and it got me thinking about the oil, mainly about the ZDDP content which is critical in a flat follower pushrods engine to prevent ware. Currently I’m using castrol classic xl20w50, however the ZDDP level is only 700ppm and the recommendation for his type of engine is approx 1600ppm for adiquate ware protection. My question is, do you think a ZDDP additive is a good thing too use and if so which one? Or is there an oil that is more suitable out there with the correct levels of ZDDP already in it, like the old castrol gtx?
Cheers Chris. 
I use Millers ZSS 20w-50 which is recommended for V twins but if you want to add more ZDDP you can buy it from Frost Restoration or Burton Performance.
Just search for ZDDP.
Morris Oils also do a 20W-50 oil specifically for air-cooled V twin engines. Spec sheet is probably on their website.
Latterly I used a mineral 20W-50 oil with about 30cc -ish of Frost Auto’s ZDDP additive, just to be sure kind of thing, so roughly 1% by volume. The oil was Asda’s own but seems to have disappeared now.
I have looked at the morris v twin oil and it has 1100 ppm of zddp, i am keen on sticking with a mineral oil. The castrol im currently using only contains 800ppm of zddp which isn’t enough but it has a low detergent level which is good when you need zddp, as a high detergent level will remove zddp from surfaces. I still haven’t decided weather its good to use an additive as i don’t want to mess up the chemistry of the oil, and adding too much zddp can damage your engine by causing oxidisation. So the other oil that i have been considering is Valvoline vr1 which seems to have great chemistry and is formulated to protect flat tappet engines and is still a mineral oil. i will still change the oil very often as i consider it to be very important to keep things in order but i still think its important to have the right level of zddp to prevent premature cam and valve train ware, as frequent oil changes alone wont stop this type of ware. i will do more research and hopefully come to a good decision.
Ooh an oil thread!
I use Millers Classic 20W-50. ZDDP level is about 1150ppm if I remember correctly. My understanding is that’s plenty enough.
I was never aware, before today, about this additive - and I have run classic guzzis for many years! I use Morris Golden Film in the Eldorado as it is better for engines without full flow filtration (so sayeth Morris!). Had a recent engine check-over and top end service by NBS and, after 60k miles since it was rebuilt, the wear was very good and nothing needed replacing. I change oil every 2k or so. In the “filtered” S3 and T3 I use Morris Super 4 10/40 “semi skimmed” and, again, no apparent problems. Up to the point I moved out of range of Corsa Italiana, I used Rock Guardian 10/40 as per their recommendation (that is what they used in workshop). Morris do not seem to publish ZDDP rates but I have established that the Golden Film is 700ppm which was deemed ok by several classic vehicle forums I looked at. No idea about the others.
years ago the zddp wasn’t an issue because it was in a lot of oils at a level of about 1600ppm, but nowadays because of catalytic converters and tight emissions they have reduced it to about 700ppm which isn’t enough protection for a flat tappet engine, I have just spoke to the chap at “Classic oils ltd” and he recommends millers classic 20w50 for the classic guzzi with an oil filter, which has great stay in grade properties and a zddp level of 1130ppm, he also recommended the Valvoline vr1 but he is having trouble getting it for a decent price, so I think im going to go with millers classic as this chap really knew his stuff and what he said seems to back up what I’ve been reading.
The reason this whole issue has come about is when I checked my cam lobe duration/lift with a DTI each lobe was measuring different so indicating ware, I have removed the tappets and cam and they show light scoring and pitting that the lack of zddp and oil changes cause, so I want to make the right choice of oil to prevent this from happening again.
You said your engine has just been checked by NBS, I would be interested to know the amount of ware he measured on your cam. cheers Chris.
PS. if you go on “Classic oils” web site all the oils and specs are there, including the Morris oils.
Yes, the same two oils were recommended by Opie Oils when I contacted them for advice. I went with the Millers cos that’s what I had been using anyway!
Hello,
Have done a shed load of research on this its a mine field! You are quite correct in saying flat tappet engines require a reasonable amount of ZDDP. too much is BAD. Lots of companies do not like to revel the secrets of their brew. It would appear that a level of ZDDP in the region of 1100 to 1500 is perfectly adequate. Regarding grade. If using bike all year round a 10W-40 would be most suitable as cold start protection with 10W is required. Smith and Allen produce a superb 10W-40. I have phoned their technical rep. It is a semi synthetic ester based (expensive base stock) oil containing ZDDP 1300ppm motorcycle specific. The ester base allows it to resist very high temp (air cooled) and ester makes the oil electrostatic meaning clings to surfaces when engine is off, good start up protection. Currently available 5ltr £14.34 20ltr £48.47. The 20ltr is great value and is what I buy. Next day delivery! The other oil I use in my fair (warmer) weather bikes is the excellent valvoline mineral 20w-50 VR1. Look around you can get 5ltr for £24. I used to use 15w-50 fully synthetic helix ultra but it is no longer available. The old Ferrari F40 designation in the specs was the key they had big flat tappets then. It was well over the top spec wise but I could get the last stocks really cheap. Forget the the nonesense about fully synthetics being too thin and causing leaks. They are simply better oils. Early Guzzi,s don,t need them. A good mineral or semi will be fine and dandy. Use good filters though I use Mahle.
I am certainly with you regarding the Valvoline VR1 and am still considering it if I can get hold of it easily, as I like to change the oil often. what you wrote makes perfect sense and again backs up all the research I’ve done into the matter.
cheers, Chris.
No idea on cam wear. Nigel has raised general wear issues with me on previous occasions so I work on principal of no news is good news! 45 years old and bike is going just fine! In a good year it will only do 2000 miles and more like 1000 so not gonna get excited! Thanks for general oil info though - something different to research other than bits for my KTM!
When I pulled my 1989 Cali III FF engine down for a rebuild after 40,000 miles the only worn parts were the cam followers so I’ve been very careful about ZDDP since the rebuild.
Where did you get your avatar from? 
And what does the bottom bit say…
Just to add to the confusion. There doesn’t appear to be much love from oil companies regarding after market additives. However the consensus would appear to be that using a ZDDP additive during running in is beneficial for flat tappet engines - but not if the oil already has enough in (such as some Valvoline oils) and is definitely not advised in large dosages as it increases the wear rate.
As for the T3, I looked in the manuals and around the web - Guzzi and Haynes agree on 10w50 for the T3. Since that’s fairly rare nowadays I looked at Valvoline VR1 10W60. According to Valvoline this oil is suitable for ‘some Moto Guzzi, Husqvarna, Aprilla motorcycle models’. It doesn’t say what year. Opie have the same oil under car and bike categories in any case.
Because I had a small oil leak from the crank oil seal and because I love an experiment, I started using Mobil1 10w60 (Advanced or Ulimate Performance depending on where you look) which is aimed at older engines but has seal reconditioners etc. It has certainly not wrecked the engine - it runs quieter and cooler and although the leak is still there, it isn’t leaking as much - down from large drops to occasional drop.
Apparently, the seal leaks are caused by modern synthetic type oils ‘washing out’ the engine and removing deposits from worn seals that effectively exposes any wear. I didn’t have a problem until I changed from mineral to semi sythetic so I tend to believe this is true.
20W-50 for old Tonti’s. Used to use 10W-40 (Silkolene 4-stroke oil) but proved to be too thin in hot weather.
When I had the Spada used to hunt specially for Castrol Grand Prix, nearest equiv to ‘SINT 2000’ but I now realise that was largely cobblers, common or garden GTX would have done.
I’ve been using Valvoline 20/50 mineral (1000 ppm is the bare minimum for ZDDP) on air cooled guzzi and trident. You can get it from any branch of Euro Car Parts in 5 litre containers at comparative price to the alternatives http://www.eurocarparts.com/store-locator
Valvoline have an informative website that gives more detailed specs