Stuck valve?
- Thread starter Tom-D
- Start date
- Joined
- Mar 2, 2005
- Messages
- 15,263
- Location
- Southeast Tennessee
- Display Name
Display name:
This page intentionally left blank
Pic one shows left valve closed, right valve stuck open, yet pic 2 shows both valves closed?
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
Second picture was after I heated the cylinder and allowed the valve to close to get the springs off. nothing particular about the burn pattern? absolutely no carbon in the middle of the combustion chamber.
PaulS
Touchdown! Greaser!
tough to tell from the pics but the valve on the right looks torched from about 1 to 4 o'clock.
Let'sgoflying!
Touchdown! Greaser!
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
biplanebob
Pre-takeoff checklist
In photos #1 and #3, is that a crack at the spark plug boss ?
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
no. just a camera glitch.
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
no just black carbon from burning auto.
Checkout_my_Six
Touchdown! Greaser!
Do ya still need us to tell ya what to do wit dat?
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
That cylinder is already thrown away what else would ya do with it?Do ya still need us to tell ya what to do wit dat?
GlennAB1
Ejection Handle Pulled
- Joined
- Oct 5, 2015
- Messages
- 4,889
- Location
- Home will always be Vandalia, OH
- Display Name
Display name:
GlennAB1
Make another lamp.
Checkout_my_Six
Touchdown! Greaser!
call the FSDO....for coffee?
- Joined
- Mar 2, 2005
- Messages
- 15,263
- Location
- Southeast Tennessee
- Display Name
Display name:
This page intentionally left blank
So, caboned up. Due to using Mogas or just too rich?
mscard88
Touchdown! Greaser!
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
It is my belief that the use of auto fuel allowed very hard carbon to build up on the valve stem. This made it impossible to remove the valve. I've seen it before but not this bad.
Cylinders this bad aren't worth trying to fix, simply because of the cost of parts.
When I overhaul an engine that had cylinders replaced I save the good ones for occasions like this. It's a shame to throw away 50 hour new cylinders when the customer wants all new, and many don't want their old cylinders back.
Last edited:
unsafervguy
En-Route
see anything wrong? its not a lycoming?
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
Doesn't work like that.. ya got to have a badge to get near their coffee mess.
This seems to be one of those chicken or the egg syndromes. I wouldn't expect a valve guide with the proper clearance would allow enough carbon to build up to cause a sticky valve. So what happened first? Carbon buildup or valve guide wear that left enough space for the carbon to build up?
What was the last fuel that got run through the engine? Unleaded or leaded? I had a valve stick on me in a Continental powered airplane that I fueled with 100LL after it had run hundreds of trouble free hours on unleaded car gas. It may have just been coincidental but I think the fuel was a contributing factor.
Tom-D
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 34,740
- Display Name
Display name:
Tom-D
Same thing here prior owner ran auto, this owner runs 100LL, some where over 100 hours by this owner.
Wish I'd saved the valve. Hard diamond like carbon on one side of the stem, badly worn on the other, guide visibly out of round.