Now this isn’t a what brand or grade, I just want to make that clear now
I’m currently building a very nice street/strip 2276 for my bay bus, always used top quality mineral oil with high zppd and all the other goodness acvw motors like. I’ve never had issues with wear, pressure or temps but with this new motor I’ve been toying with using Amsoil z-rod fully synthetic, the V8 flat tappet world rate this oil really highly.
Just after some real life feedback and opinions on synthetic oils in hot vw motors.
I have never had a "high performing" VW motor so I haven't felt the need for a synthetic. On the contrary I always felt straight 30W valvoline conventional seemed to work great and as intended. However, in my air-cooled motorcycles that have a separate tranny lubrication system I choose to use the full synthetic VR1 racing oil with Zinc. It's something I have to order. It also lasts me an entire year in that application. I'm not sure I would use it in a daily driver I was putting a lot of miles on. Motorcycles are super hard on oil so I tend to spend a bit more on them. Relatively speaking, a VW doesn't take a lot of oil and doesn't wear it out so quickly unless you have some cooling issues. I'm ok with using a conventional and just changing it more often. I would probably use Rotella 15W40 in the MIchigan summer where a slightly thicker oil would be ok. If I had a big motor in a bus working hard and creating a lot of heat I may go with a synth with a zinc additive along with a remote filter(full-flow). Synth resists all the chopping going on in a high revving high tolerance engine, right? I guess I would spend whatever you can afford, but if you couldn't, but take care of your engine well, I don't see why you'd need to worry about it in a VW. That's an opinion from someone who has never done any racing of VW's and hasn't built a lot of them. So take it for what it's worth.
I use fully synthetic 10w30 in my 2276 bus motor. Buy it in bulk so its reasonably priced. When you're spending a lot on top quality components, it makes sense to me to spend a little extra on the oil.
The bigger question here is why use synthetics at all?
Synthetic oil was a military innovation, originally formulated not for heat, but for cold. Jet fighter interceptors in artic environments leaked oil as the extreme cold shrank seals and fittings. Special synthetic oils stopped that. A bonus was that this new type of oil could be tweaked to also withstand heat better, a valuable asset in jet turbine bearings on aircraft and turbos on diesel fuel armored vehicles.
Once synthetics made the leap from the Department of Defense to commercial automotive use, most of the actual scientific benefits were perverted by marketing, and we got not just synthetic oil, but synthetic blends. Very few, if any, oil makers would reveal how much synthetic was required to be in an oil for it to be an effective blend. 2%? 10%?
The VW and Porsche community was at first not good candidates for synthetic oil, as these air-cooled cars originally operated on "low pressure -- high volume" oil systems. That's why Porsche 356's had no factory oil pressure gauge. Porsche oil pressure seemed awfully low compared to an MG. And 40 weight or more synthetics were hard to find.
Marketing made it even harder to compare apples to apples by sometimes selling blends with more thickeners as true synthetics, which at least made syn oil usable in VW engines. But the VW market was dwindling as the fuel-efficient water-cooled market was rising, and we got Mobile 1 that began as zero weight. And just to show how misunderstood oil tech is, the W in (say) 10W30 does not even mean weight. It means Winter.
The good thing about syn oil for us is it withstands heat way better. It doesn't make your engine run cooler. It means the oil itself doesn't go into thermal breakdown as quickly.
To summarize, if you really have to operate in extreme hot or cold conditions, go synthetic. Make sure the label reads 100% synthetic. If not, then true synthetics for you is a vanity. We race a 1973 2.2 litre Super Beetle in LeMons enduros, 8 hours at a time, sometimes 24, and we use Lucas Classic Hot Rod oil, 10w30 and 10w40.
I pretty much agree with FJC. After a discussion with a person teaching oil when I was a so called mechanic I asked pretty much the same question. He took me outside of the teaching truck then said off the record most all the oils by themselves were probably were OK (there were some that weren't but that, like today, were quickly discovered).
I ended up using a eastern based oil which has since been bought out by Shell (1913 to 2002) and now is synthetic based so I have to figure that one out. Last year I talked to, a retired ACVW engine builder who, even close to my age, is still racing. I asked him what he uses, and he said go to the store and just get a 30-weight oil (unless the air temperatures are part of the game then get an oil with a range to it) then just change it and the filter regularly.
I have a buddy who autocrosses a '71 Super that had a 1776cc with a radical cam (he has since built a larger engine, 1915cc I think). He ran and will run in his new engine 10w30 full synthetic with a pour in zinc additive. He's a mechanical engineer and explained his logic to me which made perfect sense and I agreed. When each of my upcoming engines are broken in, I will either run Rotella or something similar or my buddies formula.
Engineers can always talk. It's the walk that matters. Synthetic is gonna get you longer durations between oil changes. Beyond that proof of any benefit in a ACVW is anecdotal. Keep your oil clean and fresh unlike your women and it'll be happy.
Flat out....synthetic oils have two benefits that mineral oils do not.
1. Most of the good ones have lower friction than mineral oils. One of the primary reasons modern cars can last so long (yes there are design differences and material differences)...is synthetic oil.
2. They can readily operate at sustained temps of about 25* minimum to about 40* maximum...HIGHER...than mineral oil. If you drive a lot of highway miles in hot climate....this is a bonus.
The longer oil change interval with synthetics ...is NOT always a bonus in my opinion...because its readily abused and that KILLS engines.
In the beginning, synthetics were designed to run right at 2X the miles as mineral oils ...based on application. That fact has not changed. And yet we see over the past 20 years....modern car dealers running 12,000+ miles on synthetics.
Over the past 4-5 years, many companies have "quietly" backed off on this practice. This extreme mileage interval was for their benefit because why change your oil under their warranty?
And yes, synthetic oils CAN last 12,000 to 15,000 miles before breaking down....but the problem is that because it keeps fine particles suspended better than mineral oil...it gets FILTHY...and acidic. This acidity in modern cars has prime responsibility for early break down of nylons used in timing chain guides and rubber used in shaft seals.
As new car warranties have gotten longer and longer...the dealers have discovered that the long oil intervals (and long spark plug change intervals) were actually costing them money in having to fix wear items under warranty.
In my 2012 Golf or my 2006 Jetta....if they were running on mineral oil, the oil change interval should be right at 3000 to 3500 miles. With synthetic, if you track particle content and acidity...right at 7000 miles maximum. In an acvw with its high oil temps and greater blow-by....probably 5000 to 6000 miles maximum.
My 2012 Golf just rolled over 250,000 miles this past Friday. Its on the original everything in the engine including timing chain guides and runs like a swiss watch. It has gotten Mobil-1 0w-40 since day one....at 7k miles maximum.
By the way...you can buy Mobil-1 full synthetic at Wal-mart in 5 qt jugs for $28. Thats right at $6 per quart after taxes. Shell Rotella mineral oil at WM is a little more than half that price at about $16 per gallon...$4 per quart.
Saving $6 is not worth staying with mineral for being cheaper.
But....there are disadvantages. As others have noted you probably need to run an additive packaged for ZDDP....and...make damned sure you are fully broken in after a rebuild as you will never get it to break in properly on synthetic oil. Too slick. Ray
