Q: Can the Champion 37BY plug (either REM or RHM) be used on a Lycoming O-360 A1A engine? My concern is that the piston may hit the plug tip. Is this a valid concern?
DAVID M. GITELMAN, via email
A: David, thanks for your question. I’m certain others have had the same question regarding the Champion REM37BY spark plug.
Yes, the REM37BY spark plug is approved for your O-360-A1A engine. This spark plug has a unique design that allows the electrode to extend further out from the nose of the spark plug, but it will not come close to allowing the piston to come in contact with the spark plug.
I think you may be confusing this spark plug with the long reach spark plug used in several of the higher horsepower Lycoming engines. These are two entirely differently designed spark plugs.
When it comes to approved spark plugs for a specific engine, the best reference is to check out the latest revision of Lycoming Service Instruction 1042. I believe that is revision Z dated May 8, 2009.
Any FAA Approved Repair Station should have a copy available for you to look at and answer any questions you may have.
Q: I have a small problem with fowling plugs with my 1966 Cherokee 6, 260. What do you suggest I try? Different plugs? Cleaning? Is one plug better than another? Does one last longer?
JIM MAZZOCHI, via email
A: From the brief information you furnished Jim, I can think of a couple of things I’d try right off the bat. Knowing more about the engine history of this 1966 Cherokee would have made my response a little easier, but let’s begin here.
Number one is — and this depends on the particular flight envelope your aircraft flies — you may be able to clear up the spark plug fouling by simply going to a higher heat range spark plug. As an example, if your current spark plug is a Champion REM 38E, you may want to install a set of Champion REM 40E plugs since they have a higher heat range.
I’d also suggest you check to make certain that your engine is not running too rich. If the spark plugs look all black and sooty when removed, this may be a result of a rich mixture condition.
If oil fouling is the problem, then I’d recommend completing a hot differential compression check, looking for a leaking of air from the oil filler tube when the oil dipstick is removed. This would indicate excessive ring wear and will probably mean removing the cylinders for further inspection and possibly completing a top overhaul, which would include cylinder wall honing and installation of new piston rings. You might as well also inspect the entire cylinder assembly and reface or replace the valves if required.
Let’s see where this gets you and hopefully your problem will be solved.