Florida Air heads what weight oil ?

I've always been a fan of Castrol 20w50 for my bugs. It's easy to find and seems to do a great job. I thought about going synthetic with my latest engine but after getting thoughts and suggestions, found there were more contradictions than opinions. So, I stuck with the same old dinosaur juice. Works good, lasts a long time.

< TC

Another vote for Castrol 20w-50. Best dino oil out there, IMO. Leaves no sludge.

Vote three for castrol 20-50 I am near St Pete...not sure if I'll make melbourne though gotta work on my baja and Puma....

Make that four - I use it here in the uk.

Rich

AOK That is what I have used in California and in WA. state . I was wondering if I should run with a different weight being in the tropics . Hope to see you at the Volkstoberfest here is the link

yea I have the Sea Blue 1966 Bug with a sunroof restored like new almost.. Thank You , Tony

I understand that going to an extra heavy oil is the obvious thing that most people do, but I'm gonna suggest that if you think a bit more about it you may come to understand that this may not actually be the best plan.

Very few of us really run in the tropics, and temps that get up into the 90s occasionally are not really all that hot compared to what your engine normally runs at. Running heavy oils seems like a no brainer because it's just so obvious that heavier oil will keep the journals away from the bearings better.

The problem with this argument is that it skips the understanding of how journal bearings actually work. Yes, the oil gets pumped into that space, but the REAL lubrication oil pressure is created INSIDE the bearing by the rotation of the journal. Imagine what this bearing looks like when it's spinning and the journal gets pushed slightly to one side. Now the rotation of the shaft is trying to push the oil into a space that is decreasing in volume. The increase in pressure created by this "squeeze" is immense, many times the pressure that you measure in the oil galleys that supply the oil.

This increased pressure pushes the shaft back on center.

The place where heavier oil comes up short is that it is harder for the pump to pump it, and this has 2 consequences. It take more engine power to run the pump, and somewhat less oil will be pumped.

Now consider heat. You're relying on the oil to carry away a significant portion of the heat, but now you're supplying it with less oil. If you make the oil heavy enough, the pressure relief valve will open, bypassing the oil cooler, so now you have even less oil being allowed to carry heat to the oil cooler.

The end result of running heavier oil is an engine that actually runs hotter.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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..............Very well said Jim. I've used 20-50 and also synthetics and even 4-cycle motorcycle oil over the years and finally in the past year or so, I've come back to using straight 30 weight Castrol. My bug still generates about the same oil pressure at 3000 rpms after completely warming up and driving along at a steady speed (about 38 psi). My pressure at idle is still around 10 psi after it gets warmed up. The only observable difference for me is that the synthetics run almost 10 psi lower at highway speeds and lo and behold the straight 30 weight oil seems to run slightly lower head temps than the multi-viscosity dino oil and the synthetics. Your explanation of what is wrong with using heavier weight oil is exactly right from what I've read. When 1st starting up now, I use a little caution for a few miles now until the pressure is no longer pegged at 50 psi when over

2500 rpms. After that initial warmup period, I just drive normally which includes traveling at 75-85 mph on the highway that I use going to work. I wouldn't think of using straight 40 weight oil unless the weather ran a lot of 100 deg days like in the southwest. Even then, I'm not sure that I'd stop using the 30 weight stuff.

In TX I run 30 wt in summer, 10-30 in "no leaves" season (not really winter) because the temperature can be warm one day, cold the next.

With the exception of an engine designed to run a heavy oil. My Harley is one. It runs on 20-50 per Harley's recomendation. Harley uses a roller bearing for the mains and rods which do not require much pressure. The oil passages are large and the oil pumps (dry sump) move large volumes of oil at low pressure, 32 lbs at 2500 rpm's, but only

3-6 lbs at hot idle, 1000 rpm's. The facts as you laid them out are quite correct though, for most all automotive applications, the lighter oils such as 20 or 30 wt are ideal. 10-30 wt is an ideal all round oil for most VW applications.

Just wanted to interject the exception that proves the rule.

I'm using straight 30 weight Fuchs since I rebuilt the engine. I will always use

30W but may be I will change for Castrol or Motul.

Jim Adney wrote:

Joao

72 Super 1302