I’ve been searching on the site about oil recommendations for my 68 VW Karmann Ghia. I’ve had it about a year and it’s just been sitting but it’s time to spin it around. It’s air cooled of course and I know SAE30 was what they recommended when it was new, but today’s oils different/better or in some cases worse I guess for the flat tappets. I’ve read a lot on here about zinc content so my question is would Rotella T6 be a good way to go or is there something you guys would recommend? Oil is cheap, engines are expensive so the cost of synthetic oil vs conventional isn’t a concern to me. I just want good protection for it. Also what about gear oil for the transaxle? What would be good there too?
VW 1600 Rotella T6?
- Thread starter carguytroy
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High zinc is a must in these old air cooled engines, zinc not only protects camshafts but help prevent piston scuffing. There are a few ways to do this, either go with something like a HDEO conventional and use a zinc additive which is a pretty good approach as a short OCI is preferred on these or go with a V-Twin engine oil.
These tend to be a bit pricey and are synthetic, the positive side to these is they have all the zinc and other additives baked into the cake, pour in and go, the negative is the cost and some report synthetic makes leaks worse or even causes them. I don't think its as bad as reported so I wouldn't be too concerned about that.
One example with 1750 zinc which is perfect for this engine.
If using any other oil including diesel oils use this 2oz per qt for the bug engine, it is a good product for engines that need it not snake oil.
The transaxle needs only the most basic GL4 80w90, nothing special.
These tend to be a bit pricey and are synthetic, the positive side to these is they have all the zinc and other additives baked into the cake, pour in and go, the negative is the cost and some report synthetic makes leaks worse or even causes them. I don't think its as bad as reported so I wouldn't be too concerned about that.
One example with 1750 zinc which is perfect for this engine.
Amazon.com: Mobil 1 96936 20W-50 V-Twin Synthetic Motocycle Motor Oil - 1 Quart (Pack of 6): Automotive
Buy Mobil 1 96936 20W-50 V-Twin Synthetic Motocycle Motor Oil - 1 Quart (Pack of 6): Motor Oils - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
If using any other oil including diesel oils use this 2oz per qt for the bug engine, it is a good product for engines that need it not snake oil.
The transaxle needs only the most basic GL4 80w90, nothing special.
Driven GO 80W-90 Conventional GL-4 Gear Oil
Driven GO 80W-90 Conventional GL-4 Gear Oil
www.drivenracingoil.com
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Good post above. The SAE 30s of today generally do not have the ZDDP levels they did when that car was new.
Full synthetic is a good way to go on an air-cooled engine especially when cyls 3 and 4 can run 100 degrees hotter than the other two due to the oil cooler blocking airflow to the left bank. On the other hand if you have leaks, synthetics, since they flow much better have a way of seeking them out. I built my engines as non-leakers. Do you have an add-on oil filter?
Also even more important is to keep the valves adjusted regularly, typically .004 intake and .006 exhaust.
Also even more important is to keep the valves adjusted regularly, typically .004 intake and .006 exhaust.
Perhaps, but I thought the answer was that current levels were more than adequate for flat tappet engines except for break-in.
No, not at all. Zinc also helps prevent piston scuffing on these old loose fit air cooled engines. Even some newer engines with roller cams are having troubles for all sorts of reasons. I would bet a good dose of zinc and phosphorous would have positive benefits but the manufacturers cant advocate for its use.
I had a tuned engine with roller cam and had a horrific UOA, the oil company told me off the record I need more zinc in that engine, sure enough at 1400 ppm wear dropped like a stone.
You see statements like "that engine has low pressure springs so it doesn't need much zinc", this is not totally correct. The rocker arm ratio can dramatically increase pressure on the cam lobe even from springs with lower pressure.
It is true when breaking in a cam that uses high rate or double springs using a lighter single is best to break it in but even after break in and the operating springs are installed a higher level of zinc can be beneficial.
I had a tuned engine with roller cam and had a horrific UOA, the oil company told me off the record I need more zinc in that engine, sure enough at 1400 ppm wear dropped like a stone.
You see statements like "that engine has low pressure springs so it doesn't need much zinc", this is not totally correct. The rocker arm ratio can dramatically increase pressure on the cam lobe even from springs with lower pressure.
It is true when breaking in a cam that uses high rate or double springs using a lighter single is best to break it in but even after break in and the operating springs are installed a higher level of zinc can be beneficial.
Thanks for all the replies and advice. I ended up using Mobil 1 15-50 synthetic. The specs I read said that it had 1200 phosphorus and 1300 zinc ppm and I went with a 75w90 synthetic for the transaxle that said it was rated for GL4. I changed the oil etc before I had any responses. But After reading all of these I’m wondering if I should be putting a zinc additive in also? I do not have an add on filter. Just the stock set up. And you’re totally right, awguy, definitely need to check and adjust the valves. The car is going to get driven a lot more for the next few months And I’m getting it up to snuff. Doing some vehicle shake up and the wife will be driving it till our new Bronco we reserved shows up. Her idea.
You should be okay with 1300 ppm. It does no harm to bump it to 1500ppm but I don't think its absolutely necessary.
Valvoline 10W-30 VR-1 will work.
My dad used PZ 10w -40 in his beetles he bought new. A 70 and a 74 super. Both went well past 100k with no issues.
If he used the PZ back then it sure had a lot more zinc than anything recent.
My understanding is, 10w30 has about 1200 PPM before cats came in. I ran these oils in my pumped up '66 GTO and beat the snot outta it.
Everyone overcammed everything back then.
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The "old" oils were all over the place. We had some VOA's of classic oils and some had levels below what current oils are at for example.
Correct. Although known to be an anti wear additive, it wasn't used for that purpose in the day. It was used as an excellent anti-oxidant.
I have several friends who own air cooled VWs and they all swear by 20W-50 Dino.
When I messed with VWs in the old days my oil of choice was Castrol GTX 20w-50 and changed it every 3k miles. Never had an oil related problem. Now days I would probably use a 20w-50 motorcycle oil or maybe a 15w-40 HDEO.
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