Exhaust Valve #2 Stem Deposits - Normal?

by Stephen Burke in 912iS Technical Questions one year ago

Honor to those who have gone before on this Memorial Day.

I was replacing #1,2 exhaust headers for my Vans RV-12iS per Service Bulletin and observed this on Cyl #2 exhaust valve stem with just under 600 hrs on the motor, mostly Swift UL94 fueled with intermittent 100LL/Decalin and the most recent ~ 50-75 hrs Costco 93 UL/E10.

Is this normal? I was surprised at the amount of buildup. Any recommended actions to address / mitigate continued buildup?

Thanks,

Steve

9854_1_image0.jpeg (You do not have access to download this file.)

9854_1_image1.jpeg (You do not have access to download this file.)

Re: Exhaust Valve #2 Stem Deposits - Normal?

by Micha Regev » one year ago

Micha Regev

8 17 45

What SB?

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Re: Exhaust Valve #2 Stem Deposits - Normal?

by Bob Yanniello » one year ago

Bob Yanniello

22 91 191

SB-00013. And I didn’t really examine them closely, but my exhaust ports didn’t strike me as being that bad.

36204_2_SB-00013-R1-RV-12iS-EX-00021-EX-00022-1-Cracking.pdf (You do not have access to download this file.)

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Re: Exhaust Valve #2 Stem Deposits - Normal?

by Bob Yanniello » one year ago

Bob Yanniello

22 91 191

Don’t ask me why, but I had to remove my #1 cylinder exhaust pipe this morning so took theses for you as a comparison. Definitely sooty, but not alarming to me. Looks slightly better than yours. This is at 300 hrs running almost exclusively 93 E10, and Decalin when using the occasional 100LL.

36212_2_IMG_0193.jpeg (You do not have access to download this file.)

36212_2_IMG_0194.jpeg (You do not have access to download this file.)

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Re: Exhaust Valve #2 Stem Deposits - Normal?

by Roger Lee » one year ago

Roger Lee

128 5.28k 4.98k

This build up can be associated with many factors in running an engine. One person's accumulation may be different from another. Things like total engine hours, fuels, cruise rpms, plugs / gaps, engine temps, ect....

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Exhaust Valve #2 Stem Deposits - Normal?

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