Aircooled Oil Discussions

Sorry for my rantings on oil over the years, but I have never truly been happy since the Quantum Blue 15w40 disappeared from the shelves all those years ago. I use Mobil 15w40 at the moment that seems to do a good enough job but always have to be careful with my 1500 single port as it does get hot on long journeys on hot summer days. Ideally if I get the time will convert it to dog house cooling and am thinking of giving 15w50 a go next time anyway thought I would share some information found on various sites I have browsed.

The red line on each of the charts below indicates the top of 20w/50 range information from ratwell.com

VW 1978 SE recommended oil chart for passenger vehicles.
20w/50 usefulness tops out approx 75f.


VW 1988 and older SF recommended oil chart for passenger vehicles.
20w/50 usefulness tops out approx 85f.


VW After 1988 SG recommended oil chart for passenger vehicles.
20w/50 usefulness tops out approx 95f


VW have always recommend a 15w/40 multi-grade towards the later years of aircooled engines and as oil technology improved as well as in the Mexican Beetle. Engine builders seem to indicate a good 20w50 multi-grade, but it has been said that 15w/50 multi-grade would be more suitable for the van engine in moderate climates.

Other interesting note was how poorly single grades such SAE30 viscosity fair when they get hot against the multi-grades, I know a some people still use the Morris 30 stuff for some reason.

Makes good reading Daz, just after I have dumped my running in oil and added fresh Morris oil, well guess I will be dumping that now for at least the 15-40

Ta for info

Ron

No worries Ron, there is not anything wrong with using Morris 30, people have been using it for years, I never got on with the stuff personally I found the engine run hotter with it, just my opinion but in the aircooled VW world it seems to be well branded and bit over priced. I switched to 15w/40 after a chance visiting a local VW dealer in Hayes many years ago and they at the time recommended using Quantum 15w/40.

Anyhow I have just bought some Fuchs Titan Superma 15W-50 hopefully if it comes before the weekend I will give the Junkyard a service and see how that fairs.

I am sure a while back having a conversation with Owen about using 15w50 motorbike oil along the same lines but I might be wrong.

Daz

owen wrote:Think you have  just opened a can of worms rather than oil Daz,


 There are two mains things to think about when looking for oil one is its viscosity and then other whether it contains sufficient additives for our type of engines. Also depending on the age of the engine and how worn it is another factor. All the engine builders quote different things as well. If you get really bored there is a 160 page thread on the samba plus another 40 odd for gear oil. ( they seem to like 30 grade muiltigrades )
Personally   I think 20/50 is too thick for new engines but fine in worn ones with slack clearances unless you are reving the guts out of it down the strip.
Motorcycle oils are great in the fact they are better suited for air cooled engines and contain higher zinc and phosphates to lubricate the type of valve train we have.

If you look at the API rating on the tin you really need something like an SJ rating that gives the right zinc levels this rules the newer oils but something like morrisons (as in supermarket) 10w 40 is fine as per laurie pettite's suggestion.
The newer oils don't have zinc in because it damages the newer cat convertors but bike or racing oils get away with it

I use a 10w 30 oil either Motul of Castrol power 1 which is a m/c oil, tried using a thicker oil on my new engine and it was blowing out of every place possible and oil pressure was sky high.
Think a lot of new engines have a too bigger oil pump and if you use a thick oil in the winter you run the risk of blowing a hose or filter but older engines with looser tolerances are fine as it was with my old engines.
I used to run beetles on straight 30 grade and bought it by the drum load and never had any problems with it.
Any oil is better than none so each to his own just find something you are happy with that works for you and keep quiet about it. We change our oil regularly and with only 2.5 litres I don't think price or longevity  is much of a concern.

LOL - Cheers Owen I never got on with the Morris 30 to be honest and have always run 15w40 but I know the old single port does take a pounding on long hot journeys.