IO-540 Slick or Lycoming EIS mags

I plan on putting in my engine order before the March 15th price increase and I am torn on which mag option to go with. If I go with the Slicks then I will need to add the $1,100 Slickstart module. If I go with the Lycoming EIS it will add 2k to the price (about 1K delta if you include the slickstart). I don't understand why it is a 2k option since on spruce the surefly is about the same price or cheaper than the slick and the Lycoming EIS is based on the surefly.

I would order it with no mags and get the pmags or surefly but that is only an option on the thunderbolt. If it were you which would you do?

I ordered my IO-540 CAS from Thunderbolt engine with no mags. I will install dual six cylinder pMags on it. This pMag is now flying on my old RV-10 for well over a year and has provided significant increase in cruise efficiently.

I suspect at some point Thunderbolt will ship new engine with this pMag, just like they now do for four cylinder engines.

Carl

Nobody else has an opinion?

SureFly

We ordered IO-540 D4A5 with standard Mags, (before last two price increases) once received we removed one Slick and installed a SureFly on one side only. Starts very quick & smooth. Still have the new Mag for a backup and/or future replacements. Sold the old Engine to JB in FL. Very Happy!

I've got two Slicks on my IO-540, without slickstart or any other supplemental boost. Mahlon (actually David - signature on the block!) built me a good one!
Always starts quickly, hot or cold, and I would be happy to continue with this.

I do have a 6351 Slick subject to the recurring 250 hour impulse inspection, though - and I'm considering replacing it with a Surefly one of these years....

If I were to do it again, I would order a single non-impulse mag on the right, and a Surefly on the left....

Phil
RV-10 built/flying
Bountiful UT

I don't think the IO-540 (at least the ones from Vans) come with impulse coupled slick mags. It states on vans' site

Requires Slick-Start booster system

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Yep, that's correct - you won't find them on the current 540 engine builds.
When Mattituck built mine, there weren't as many EI options, so I went old-school.

That's why if I was building up now, would do a non-impulse and a Surefly - don't have to monkey with the slickstart, and the reviews I've seen on the Surefly have been pretty favorable. I'm pretty accepting of new technology, but I've been a Luddite when it comes to mags.

Thankfully, done with the -10 build given current supply chain issues. (although 5 crates are enroute from a certain Canadian company - I couldn't wait for the RV-15 to come on line)

Phil

philb said:

Yep, that's correct - you won't find them on the current 540 engine builds.

Phil

Click to expand...

That’s because they had a bad service history, of impulse couplings failing. Supposedly due to some harmonic vibration. That’s why you have the 250 hr inspection requirement. If yours fails, it might drop parts down into the gear train, with ugly results.