Is there a benefit to using fuel additives?

I have recently received several inquiries concerning the use of aviation fuel and lubricant additives. To start a discussion on additives, I’ve looked into any and all approved additives.

In the ASTM D-910 spec for 100/130 low-lead avgas, there are only two fuel additives approved for aircraft owner addition to the fuel: Isopropyl Alcohol and Di-ethylene Glycol Monomethyl Ether. Both are fuel system icing inhibitors.

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Ask Paul: How should I handle chromed cylinder removal?

Q: When an engine with chromed cylinders comes into a shop with oil leaks and the source has been identified as thru bolts and cylinder base o-rings, how should the cylinder removal and reinstallation be handled? Also, is there any wisdom in turning the oil scraper ring upside down in chromed cylinder to help control oil consumption?

JAMES FINLAYSON, via email

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Ask Paul: What is causing mag drop?

Q: I work on a IO-360-MIA Lycoming engine. My problem is that the right mag has a drop of 220 rpm. I have done internal timings, engine to mag timings, ignition leads check and cleaned the plugs. I have done nothing to the left mag, and now the left mag is dropping to 210 rpm.

ANGI LISA CHAMBERS, via email

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Ask Paul: What’s causing intermittent roughness?

Q: I am an European-based A&P with a customer who is experiencing intermittent roughness and loss of rpm (200) typically close to the top of climb on a long climb out. The roughness goes away once it is throttled back, and it does not occur all the time. The snag can’t be produced on the ground. The aircraft is just off annual check and had the 1,000 hours mag inspection carried out, apart from various other visual inspections, plus the routine other items.

I’ve thought about the possibility of a sticky valve, an issue in the carb venturi or some issue with the mags, but thought if it were any of these that the issue would be there all the time?

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A Q&A with Lycoming’s top man

Michael Kraft

After Oshkosh, I sent an email to Michael Kraft, Lycoming’s senior vice president and general manager. Due to this busy travel schedule, he was just able to get his answers to me. To honor his request, I agreed to run this in a Q&A format.

Q: Is Lycoming working on or considering development of a diesel cycle piston aircraft engine?

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