Oil for VW aircraft conversion

[BillWilson]

I am building a Thatcher CX4 powered by VW conversion. The 1915CC engine will be used with improved heads, low compression for auto gas, forged crankshaft, and oil drain to be every 25 hours. The supplier recommends 30W or 10W30 automotive oil for break-in and normal operation. Other VW builders also use 10W40 & 20W50 automotive oils. I am not aware of synthetic being used for this type of application. The engine will not be assembled until ready for test flights.

I plan to use unleaded auto fuel most of the time with occasional 100LL use. I live in southern NC and fly with temps from 30F to 95F. My flying time will be about 100 hours per year.

Just wanted to hear suggestions about oils to use. I have been considering Rotella T 15W40 (used in my motorcycle & pickup) and aircraft oil. You can use the link to my website in my profile section that gives more info about the CX4.

Thanks,

 

[bmwtechguy]

The Rotella should work fine. If you want to use synthetic, you could consider their 5W-40 which is a reasonably priced synthetic that performs well. The main advantage would be better startup flow on the really cold days. Years ago we used a synthetic oil called Amsoil in a 10W-40 grade in air-cooled VW's and it outperformed anything else we had tried up till then. I'm sure that they still make several oils that would work really well in your engine. The only problem with using a higher priced synthetic oil (Amsoil) in your engine is that if there is no oil filtration to speak of, you still have to drain it fairly often, which negates one of the advantages of a synthetic lubricant- safely extending the drain interval.
Should you decide to try synthetic, conventional wisdom is to do your break-in on regular petroleum oil on the first oil change or two.

 

[BillWilson]

I have been impressed with Rotella T in articles read and for the short period I have used the 15W40 in my Toyota Pickup and Yamaha motorcycle. Since I posted this question in this section and BITOG Auto section, I will pass the threads on to the CX4 builders.
Thanks,

 

[Johnny]

Bill: I posted under this heading in the automotive section so I won't repeat myself here. Good luck with your project.

 

[Rick_A]

Bill,

I built up an 1835cc conversion to use in my Evans VP1 (Volksplane). I have used some type of Valvoline 30 wt oil since I built it. I started out with 10W30 and eventually changed to straight 30Wt Valvoline racing oil. I have had good luck with 30 wt oils in the VP1 and my off-road cars.
I have also had good results using Delo 15W40 in my turbocharged off-road car (also vw engine). Unfortunately I didn't do any oil tests.
The VP1 engine case has be tapped for a full flow oil filter and I use an automotive filter mounted on the firewall. I originally had a stock VW oil cooler mounted on top of the engine but later changed to a larger cooler mounted on the belly of the plane. I should have stayed with the original cooler. I was seeing oil temps up to 220 degrees here in Calif. on warm days. Now it's hard to get the oil up to 180 which I feel is too low.

Good luck with your project,
Rick

 

[Propflux01]

15w-40 should work fine since your not in altitudes of lowered temps.

 

[BillWilson]

Rick,
Thanks for sharing your experience. I also answered you in the auto section. I plan to use 30W for break in and have not made the final decision for the oil after break in.
Tim,
I am running 15W40 in three vehicles so far, and I am very impressed with Rotella T. There has been discussion about deposits building up faster with non aviation oils. My hopes were Rotella T may also help prevent deposits. Comments are welcome on this issue.
Thanks for the input from everyone,

 

[Propflux01]

I think the Rotella T or even Delo 400 Will serve you well...

 

[BillWilson]

Tim,
I just started using Rotella T in two vehicles with over 210,000 miles each and one air cooled motorcycle. By the time I have the CX4 completed, I will have tested the Rotella T.
Best Regards,

 

[richter1]

I'm familiar with a Volksplane that has been using Rotella T 5w40 for the last 300 hours. It is performing well.

 

[jimvegas]

I use Motorcraft 30W Diesel oil in my '61 vw beetle 1200cc 40hp. I had tried 15w-40, but it likes the 30W better. The old 40hp has smaller oil passages than the newer blocks, which may have something to do with it.