piggy said:
Thanks SiDev - running with around 3.4litres and it seems more steady now.
Paul,
My understanding was that the air cooled VW engines run best on single grade as multigrade goes too thin at the higher running temperatures over a water cooled. 15/40 in my opinion would run too thin when hot, I did run a 20/50 on an old engine but had a bearing failure so have returned to SAE30.
I will be doing a proper run in on this engine so it will be serviced after first 500 miles, then after next 1,000 (or probably 500).
Thanks,
James
Here are a few things to look at regarding oil an viscosity etc:
http://www.upmpg.com/tech_articles/motoroil_viscosity/" onclick="window.open(this.href);return false;
And here:
http://www.vw-resource.com/engine_oil.html" onclick="window.open(this.href);return false;
SA30 is 30 at low temperature, thick, and not as fluid for quick lubrication on cold sat up, where as a 5W30 is thick (30) at running temp, but has the equivalent of a SAE5 at cold temp, hence the W, hich is better for initial start up lubrication, which is one reason why a multigrade is better, now that these modern oils have been developed over a straight grade...
Though saying that, the additives in multigrade to improve viscosity will break down over time/heat/etc and will make your oil thinner at the higher temps, so you may end up with a equivalent to SAE10, not as good.....
The W is for winter/cold use, which will give us more protection in our cold UK climate, whereas, technically you should change the SAE30 for winter use/season change.
Personally, I have a decent multigrade 20W40 20W50, and change it regularly, this oil is pretty cheap, I have used SAE30 before, no problems with it, or multigrade, I can't see how running a multigrade would cause a engine to fail, unless it was degrading over time/heat/contaminants etc and running too thin..
I think the only reason why a straight grade was recommended at the time, is that this was the only thing available, as the then commercially available multi grades weren't reliable, the later bays use multigrade from 1975
So IIRC, in theory, a 20W50 will give better protection starting from cold, and better at running temperatures, though will likely to thin out at extended intervals due to the breakdown of the additives, but as you will b changing at around say 3k+ it is unlikely to be a problem.
Though aside to the standard viscosity ratings, there are many oils designed to work better on certain types of engines, such as roller bearing engines as well as air cooled, and then you have the mineral/semi/fully synthetic argument too....
Not wishing to turn this into a oil thread though.....
:lol:
Alistair
