Visser's Voice

After a review of the notes I received last year, the number 1 area of interest again was octane and engine knock. The latest question was about blending octane number. For example, if you blend a 100/130 (commonly referred to as 100LL) fuel with a 90 octane mogas, will a 50/50 mix give you a […]

In a past column I gave some background on what happens during break-in of a new or overhauled aircraft engine. Since then I have received numerous questions about why leaded fuel is needed during break-in. Unfortunately, I do not know anyone who has a perfect answer for this. My opinion is based on lab tests […]

In a recent email, a pilot related a problem he had with his aircraft: He needed to drain the fuel tanks so that he could repair the wing. He drained the 100LL out of the tanks into two plastic drums. The fuel sat in his hangar for several weeks and then outside in the sun […]

In my last column, Breaking in a new engine in the Aug. 24 issue, I discussed the mechanics of breaking in an engine. In this column I will discuss some of the steps every pilot should take during break-in. The first decision is what oil to use for break-in. Here, again, you need to refer to […]

I recently received an email from a pilot who lives in a remote area where 100LL is not readily available. He was thinking about buying a used tank that had been storing #2 diesel fuel. He was wondering if it could be safely used to store 100LL. I debated the answer for quite a while […]

I’ve always thought the term “breaking in a new engine” was a strange expression. What are you breaking? Why not call it wear-in? Well, we can’t change tradition. The main part of break-in is to wear in the cylinder walls to provide a better sealing surface for the piston rings. When a new cylinder is ready […]

In a recent column, “For oils, it’s all about the chemistry,” I wrote about the difference between automotive and aircraft engine oils and why you should not use automotive oil in a certified aircraft engine. I’ve since received two similar questions about adding anti-wear additive zinc dithio phosphorus (ZDP) supplement in experimental aircraft engines. ZDP supplement […]

In my last column I talked about the use of the preservative oil, Aeroshell 2F, to prevent rust in idle engines. I have since learned that Shell is phasing 2F out and in the future will only offer Aeroshell 2XN. Before you panic, let me explain. 2XN is just the additive system out of 2F. To […]

Just about every month I get several questions concerning the difference between aviation and automotive engine oils. This month I received a question about using Aeroshell 2F in a vintage automobile and the ever popular question about why one should not use automotive or heavy duty engine oil in their aircraft engine. The answers always […]