The Sticking Valve Syndome

[DanH]

Originally Posted by Bill.Peyton

Dan,
In my case the newer valve guides didn't really make much of a difference.

You have a parallel valve 540, yes? Current curiosity question involves sticking with late model (circle C marked) angle valve heads.

[Bill.Peyton]

Yes, you are correct I have a parallel valve

[aerhed]

So, Ryan had an angle sticker. That's one. I don't claim they don't stick, just that I haven't seen any to remember. Leak for sure, 470's suck.

[miyu1975]

Originally Posted by DanH

Of course, the next question would be "What vintage angle valve?"....old or new valve guide material?

Difantley old guide Dan.

[boomer]

[quote=Bill.Peyton;1008006][font="Arial"][size="2"]I thought I would post this in the RV10 list since it applies to the IO540 D4A5 typically installed in the RV10, although feel free to move it.


Lycoming Service Letter No. L197A (Supersedes Service Letter No. L197) January 19, 1988 (http://www.lycoming.com/Portals/0/te...Avoid%20Valve%) details a few techniques to minimize valve sticking, including not taxiing at idle and running up the engine to 1800 rpm before shut down.

-John

[Bill.Peyton]

Thanks for posting that, the link does not work, but here it is...
http://www.lycoming.com/Portals/0/te...20Sticking.pdf

[jjconstant]

The second last paragraph of the Service Letter:
"Prior to engine shut-down, the engine speed should be maintained between 1000 and 1200 RPM until the operating temperatures have stabilized. At this time the engine speed should be increased to approximately 1800 RPM for 15 to 20 seconds, then reduced to 1000-1200 RPM and shut-down immediately using the mix- ture control."

I'm just wondering about the practicality of using run-up power for 20 seconds immediately prior to shut-down when you've taxied to transient parking and you're blowing debris all over the ramp...it's bad enough when people goose the throttle to pirouette into the parking spot but even that ain't run-up power Doing this in the hangar rows would also not win you a lot of friends...

[DanH]

Originally Posted by jjconstant

At this time the engine speed should be increased to approximately 1800 RPM for 15 to 20 seconds, then reduced to 1000-1200 RPM and shut-down immediately using the mixture control."

I'd love to hear the technical reason.

I'm just wondering about the practicality of using run-up power for 20 seconds immediately prior to shut-down when you've taxied to transient parking and you're blowing debris all over the ramp...

That's been a constant problem with operators of the M-14 radial. They have a legit reason, but I'll bet a Lycoming user gets cussed....

[BillL]

Originally Posted by DanH

I'd love to hear the technical reason.

Ethylene dibromide

That's been a constant problem with operators of the M-14 radial. They have a legit reason, but I'll bet a Lycoming user gets cussed....

Here is the Shell answer man explanation - it sounds just like the wording of the Lycoming SB.

http://www.shell.com/global/products...-30071600.html

I have no personal experience, just looked it up. It sounds like more of an assumed root cause and an assumed solution to the temperature issue.

[boom3]

I've been operating my new IO-360B1B for about 625 hours. (Fixed pitch prop)

I've never experience any lead fouling until I started working on getting my Instrument Rating going again. It's hard to avoid the prolonged low power settings during approaches and it's really tough coming IFR over the mountains at 10,000 ft and to get down to even start the approach.

I have now upped my spark plug cleaning and rotation to 40 hour intervals when I change my oil.

I've also started running it up to 1800 for a bit before shutdown. (I only do this when there aren't planes, vehicles, or people behind me.)

While I have the airplane apart I have also decided to check my exhaust valves for any stickyness. So far so good but I have 2 to go. (I do have the newer valve guides "C" in a circle but decided to check anyway.)