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Time for a new cylinder

Thor RV10

Active Member
It’s now time for a cylinder replacement. My purchased new IO540 in 2015 now has 857TT and 1100 Hobbs. Number 2 had a low compression reading 80/18 and after new valve guide, I’ve decided to just replace it with all new.

My question is this: Anyone have experience with a certain brand of cylinder replacement such as Superior, etc? If so where did you order from and which model?

Any advice and ideas will be appreciated and thanks in advance.

Thor
 
Before replacing anything I’d want to know how a 1000 hr cylinder can have such poor compression that can’t be fixed with valve work?
As to your question: I used to hold Superior in high regard, but after the crankshaft fiasco (where they won’t make good on brand new cranks) I’d be cautious about doing any business with them.
 
I would worry more about getting a cylinder of any brand than what manufacturer. They are very scarce at the moment. You might want to consider a rebuild on that one if it is in fact a cylinder issue.
 
I had to replace a cylinder at 800 hours on a factory new engine. I had something get stuck under an exhaust valve, which overheated the valve and seat. At the time, I was able to obtain a new Lycoming cylinder locally the same day. I then sent the old cylinder out and had a new guide and valve installed and the entire cylinder overhauled. It took about 2 weeks to overhaul the cylinder. I keep this spare cylinder in case I need it in the future, it's on hand.

In today's environment, you may have a hard time getting a new cylinder. Update It appears that Airpower and Aircraft Specialties has the 05K2-1104 in stock.....
 
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Cylinder Work

I recommend Sal's Aircraft Cylinders in Prosper TX 972-346-3339. They are an old-time shop and Sal and his son have many years of experience. They do good work and are pretty fast.
 
I just had 4 Titan x-340 cylinders overhauled by Gibson aviation. Turnaround took about 8 weeks but they look good.
 
Thanks Bill. I just ordered a new LYCOMING for 1800, full set. I am going to let them install my old cylinder with new valve and guide as its in good cond. and install the new one this winter as i know #2 takes the most stress anyway. I am down here in Mexico and very happy with the mech., not to mention $200.00 per day rate.
 
Bob, The valve is showing hot on top and the guide needed replacement. They commented that the cylinder and rings looked in excellent shape. She doesn’t burn any oil and i bought the LYCOMING new in 2015 and since have 1100 Hobbs time. I would show a picture but i doing know how to upload.
 
I recommend Sal's Aircraft Cylinders in Prosper TX 972-346-3339. They are an old-time shop and Sal and his son have many years of experience. They do good work and are pretty fast.
I don’t know if anything is happening fast these days; my set of 4 cylinders have been at Sal’s for over 6 weeks with no end in sight. They are ECI Cerminil jugs though, so apparently they need extra processing and time.
 
Thor, you might want to consider getting a copy of Mike Busch's book, "Engines." It discusses this sort of issue and others. It's definitely oriented towards the owner.

Dave
 
Thanks Dave. I think i did, but its on my bookshelf at home. I sent an email to him and he suggested that i try to fix it in place w/o taking the jug off. Turns out that i needed to anyway. I appreciate all that mike has to say, so i agree with you.
 
Interesting combination...short life, hot valve, and worn guide, then a new guide followed by valve sealing failure.

The combination suggests a valve seat machined non-concentric with the guide, i.e. manufacturing error. It happens.

I assume Mike told you to lap it. Try if you wish, but be sure to take a close look at the seat contact pattern when you're done.
 
Thor, I have messaged you with my email so you can send some pics of your issue. We can all learn from your problem. Turbo out.
 
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here are a few pics from Thor to help understand his issues. :)

A1-E622-B4-5126-40-F6-B6-D7-0-AC974-B12-F56.jpg

68696-D99-ED54-41-E8-9-B7-C-5895498501-F9.jpg
 
Dan, yes, Mike did suggest lapping first. I did let the EGTs get hot in the past because i took mikes advice regards to EGT temps being meaningless. I will keep them down while in cruise flight from now on. As an asides, i have been under the impression that 1100 Hobbs is pretty common to replace a jug.
 
Dan, yes, Mike did suggest lapping first. I did let the EGTs get hot in the past because i took mikes advice regards to EGT temps being meaningless. I will keep them down while in cruise flight from now on. As an asides, i have been under the impression that 1100 Hobbs is pretty common to replace a jug.

Mike is correct on both counts.

In sutu lapping ("the rope trick") is a method of cleaning a seat and valve's mating surfaces. It will not permanently cure a valve sealing problem created by misalignment, or if the original seat cutting work was poor. It mostly just clears deposits, but sometimes it's all that's needed.

Old school production valve seating is done with a shaped stone, followed by lapping. The lapping smooths the contact face, and identifies its width and location. Photo coverage of the process here:

https://www.kitplanes.com/how-the-pros-do-it-5/

Much of the engine world no longer uses abrasives, instead employing shaped cutter inserts. Barrett, for example, switched to a Serdi machine years ago.

https://www.serdimachines.com/uploads/6139c95b081ee/techno-live-pilot.mp4

Abrasive or cutter, the key is an accurate relationship between guide and seat. If it's not there, a lapping fix will be temporary.

Mike is also correct in that there is no EGT temperature limit for a normally asperated Lycoming. The temperature you see on your gauge is only an average anyway, not the actual gas or valve temperature. For us, high exhaust gas temperature is only harmful given one circumstance, poor valve seating. If the valve does not seat properly, it cannot transfer heat to the cylinder head. The non-seating portion of the valve circumference gets hot, sometimes hot enough to melt.

I typically cruise at ~65% and peak EGT. Recent leakdown was a 77 and three 78's, at a little over 1000 hours. Excellent valve seating; thank you Monty.
 
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Dan, your details here are very helpful and this information is what made up my mind to give very little credence to the EGT. I am going to continue with the habits learned from Mikes years of wisdom and use my new bhoroscope, likely every six months. My compressions are ranging from 80/74 to 80/78 in the other 5 cylinders.

Thanks, Thor (i pay my financial dues to keep the site going, but I don’t know how to put the moniker up)
 
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