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The Rope Trick - Field Repairs 101

Is the intake valve rotating properly? In the picture it appears to be stuck in one position? Maybe it's the picture and it's just oil on the stem. Or maybe it has caps?
Those engines don't have roto coils. I do know the IO470's and IO520's only have them on the exhaust valve.
 
Great write up. Got to do this recently on my brothers J3 about 60 miles from home in a 20 kt. wind. Those Airstreak tires make the engine go up and down a lot, like working on a sea plane in the surf. I have used a coat hanger and some sandpaper before when no other tools were available.
 
Great write up. Got to do this recently on my brothers J3 about 60 miles from home in a 20 kt. wind. Those Airstreak tires make the engine go up and down a lot, like working on a sea plane in the surf. I have used a coat hanger and some sandpaper before when no other tools were available.

Isn't is fun to do when the plane is trying to fly and you have a fuel strainer for a screw driver and no other tools? Ha ha.
 
Now that the engine is back home, I have it in my IA's shop along with the obligatory blank check and an intravenous tap to my bank account. Although I've not seen inside the rocker covers since I buttoned her up in MN, but I'm pretty sure what you see in the picture is a drop of oil hanging on the lower part of the valve. An optical illusion making it look like all the wear is on the top edge. I will double check still though.

Those engines don't have roto coils. I do know the IO470's and IO520's only have them on the exhaust valve.
 
I'm going to get a chance to use the rope trick on Friday. Found 64, 78, 78, 78 during the conditional on the SQ-2, and could hear air in the exhaust. CHT's are even so I was hoping this was just some carbon or lead build up. I use Marvel Mystery Oil about every other fill up to combat lead build up but decided to run a few tanks of fuel with TCP added to it. Just finished that and instead of doing another compression test I decided to buy a borescope (ouch!) so I could actually see what is going on. Am pleased that the exhaust valve has a standard burn pattern, so nothing detrimental has happened yet. I could also see a little black carbon build up in one spot between the valve and its seat. So Friday I'm going to fill the cylinder with rope, pull the valve spring, and lap the valve to the seat. Hopefully that fixes the problem. Crossed fingers & toes.
 
If you're working in a shop, it's pretty easy to do this with air pressure from your compression tester rather than rope, but either will work. With rope you don't have to worry about the prop whacking you. :behead:

-Cub Builder
 
Executed rope trick today for a stuck valve. Reamed. Grateful to be back in business until OH this winter.


Sent from my iPhone using SuperCub.Org
 
I recently had a valve issue on the RANS's Rotax. 20 over 85! When I took the head to "my" mechanic, He turned it upside down, squirted some brake cleaner, or maybe it was carb cleaner, (not important what it was, something he had handy and that stayed in a fluid state for a bit) and when it ran out the intake valve, the mystery was solved. He popped the valve out, and discovered the factory in Austria had missed a step, the valve seat wasn't ground [down deep enough. So, little sealing area, thus the leak. With no damage to the valve, he quickly ground the seat down to the correct depth and angle, put the valve back in, did the leak test, and I was good to go. Total elapsed time, both of us BSing the entire time, was 20 minutes. it was worth the 4 hour drive (1 way) to Elko, got it fixed plus got educated. Hal Stockman, mechanic virtuoso!
 
Hal could be the replacement for this dude as the second most interesting guy in the world;-)
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Hal may also be the nicest
 

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A thing I've noticed: is every heavy equipment .mechanic ( Hal's day job is fixing giant mining equipment, and he is highly respected and sought after in that field) I have run across are physically unimposing guys. Shorter and lighter than average is what I mean, the wizard that fixes my crane can't weigh 130 pounds, but is tough as nails and knows his biz like no one else in my area. Could be a coincidence, or some deep physocological thing, but get those guys around the biggest equipment made and stay out of their way, they get it done!
 
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