Ask Paul: Are these spark plugs approved for my plane?

Q: Could you please help my pretty blonde wife and myself with our spark plug problem? We are desperate! Our mechanic is going to put the new fine wire plugs we just bought into our 1976 Cessna Cardinal RG, but we have conflicting information on the proper plug.

We bought some SR83P plugs from a dealer at Sun ‘n Fun, who assured us that the plugs were the same as the Champion fine wire plugs that fit our Lycoming IO-360-A1B6 engine, and that they cross-referenced just fine.

JIMMY & SANDY HONEYCUTT

A: After doing some research of Lycoming Service Instruction 1042Y dated Sept. 1, 2009, which covers all “Approved Spark Plugs” for all Lycoming engines, I was afraid you may have a problem because there is no SR83P listed. I had a strange feeling about this, so I did some further checking with an old friend from the industry, Frank Gurko, who spent nearly a lifetime with Champion Spark Plug Co., then started his own company, PlugGuy.com, after retiring. He confirmed the SR83P spark plugs you bought are approved for your IO-360-A1B6 in your Cessna Cardinal RG and will work fine to replace your present REM38S plugs.

It would appear that there was an oversight by Lycoming during its last revision to SI 1042Y from earlier versions. As a matter of fact, the SR83P was shown as approved for your engine in SI 1042X, which I believe was dated in 2002. I discussed this with Lycoming and they will address this oversight when SI 1042 is next revised. So Jimmy, it looks like you’re good to go with the SR83P spark plugs for your engine.

I really appreciate you sending in your question because it reminded me of something I’ve been meaning to address. I’d like to make certain all readers understand that the outcome for Jimmy could have been much different had these spark plugs been the incorrect type for his engine. If incorrect plugs had been installed, there is the possibility that several nasty things could have happened and none you’d like very much. As we all know, fine wire spark plugs are very expensive, but when you put your money down and later learn they are not approved for your engine, it really gives you a sick feeling in the pit of your stomach, not to mention a dent in the pocketbook.

I’d like everyone to do one simple thing that may save you some money in the future — and, besides, it’s just a commonsense thing to do if you are an aircraft owner. Before you do anything else, sit down and make a short list that you can carry in your wallet with information about your aircraft. Most important would be the specific engine model and its serial number. You should also list the spark plug part number currently installed and the oil filter part number. These are probably the two most likely items you may be tempted to buy when attending events such as AirVenture and Sun ‘n Fun, where quite often various vendors will offer “show specials” at attractive prices. If you are not armed with the basic information and “you think” you’re buying the correct part number and find out once you return home that was not the case, then you’ve got the hassle of either returning them to the vendor and possibly paying a restocking charge, in addition to shipping costs, or trying to find someone to sell them to. So, ask yourself, was the “show special” price really worth it? If you’ve got your list, you may avoid this type of situation and come home having saved a few bucks.

I hope everyone would consider making a list, so spread the word when you’re sitting around “hangar flying” or at your EAA Chapter meeting, or just having coffee with other flyers. Maybe someday someone will be glad they made their list, especially when it saves them from spending money on an incorrect part.

Paul McBride, an expert on engines, retired after almost 40 years with Lycoming. Send your questions to: [email protected].