Skymaster Forum  

Go Back   Skymaster Forum > Messages
Register FAQ Members List Calendar Today's Posts

Reply
Thread Tools Rate Thread Display Modes
  #1  
Unread 12-13-23, 03:36 PM
n86121's Avatar
n86121 n86121 is offline
bigcheese
 
Join Date: Nov 2003
Location: Potomac Airfield~!
Posts: 329
n86121 is on a distinguished road
Unhappy exhaust valve in front mid cyl #3

On a trip to Florida with "La Wife"
about 10 mins after a normal takeoff I noted a subtle vibration.

Being the reflective mathematical sort I made the following calculations:

To keep things simple, assume 2400 RPM
Divide by that's 40 rotations per sec
4 stroke engines take 4 strokes to produce on power pulse
Or about 10 power pulses per sec from each cylinder

The vibration 'felt' around 10 hz,
suggesting one cylinder unhappy somewhere.

To land, or continue, hmmmm.

Then, after maybe 10-15 mins it cleared up.

----

Now comes my annual "wallet-ectomy"

#3 cylinder, front engine, passenger side... 20 PSI. WHAT?
Borescope shows attached image for its exhaust valve.

So sad...

As you can see the valve is NOT rotating, and 20 PSI it is not closing all the way.

My gurus here tell me
The vale NOT rotating as it should,
'green edges' are from severe over-temp, aka a 'burnt offerings'

While one might be able to lap in place and pretty it all up,
the metal is cooked and WILL fracture at some point.

Sigh...

My options were
1. Have it pulled, send to shop, change vale, pretty all up and return to service $1.2k
2. Overhauled cylinder if available $1.6k - but not available!
3. Buy new $2.3k - available same day shipping

For time and value I bought a brand spanking new cylinder.
I figured project would go faster if kit IN hand.
And, I will keep the one coming off to have on hand if I need to OH it later.

==========

QUESTION: Mine is a turbo RSTOL = Pile 'o crap on each engine.
All that stuff is top notch great shape, but there a lot of it.

I can't complain. It is a factory new engine back in 1998 w only 600 hrs on it.
I don't fly a LOT, but do so regularly.

QUESTION 1

Any ballpark idea of how many hours to remove/replace a mid cylinder like this?
It looks like a royal pain aux derriere.

QUESTION 2

Am I over reacting? Should I just have had it lapped / ground in place to see what happens?

Your feedback, comments, reassurances and sympathies will be appreciated.
Attached Images
File Type: jpg unhappy valve.JPG (29.6 KB, 1754 views)
File Type: jpg unhappy valve 2.JPG (67.8 KB, 1801 views)
__________________
David Wartofsky
Potomac Airfield
10300 Glen Way
Fort Washington, MD 20744
Reply With Quote
  #2  
Unread 12-13-23, 07:12 PM
mshac's Avatar
mshac mshac is offline
Registered User
 
Join Date: Aug 2020
Location: North Texas
Posts: 763
mshac is on a distinguished road
My guess is 8-10 hours.

There's a cylinder shop near me that will IRAN a cylinder for pretty cheap. Usually around $500 and comes back looking new. Maybe have your old one done so it can sit on the shelf as a spare?
Reply With Quote
  #3  
Unread 12-14-23, 06:36 PM
mshac's Avatar
mshac mshac is offline
Registered User
 
Join Date: Aug 2020
Location: North Texas
Posts: 763
mshac is on a distinguished road
Here's two rebuilt cylinders near me for $800 each. Sounds like a great deal.

They're done by Gibson, that's the shop I was referring to in my previous post: https://dallas.craigslist.org/ftw/av...696551439.html

If the old boy doesn't want to ship, I can pick them up for you and ship them to you (at your expense).

Last edited by mshac : 12-14-23 at 06:41 PM.
Reply With Quote
  #4  
Unread 12-14-23, 07:56 PM
Frank Benvin's Avatar
Frank Benvin Frank Benvin is offline
Registered User
 
Join Date: Apr 2002
Location: CYCD
Posts: 336
Frank Benvin is an unknown quantity at this point
Ad says Lycoming ??? - 337'S have continental's


Quote:
Originally Posted by mshac View Post
Here's two rebuilt cylinders near me for $800 each. Sounds like a great deal.

They're done by Gibson, that's the shop I was referring to in my previous post: https://dallas.craigslist.org/ftw/av...696551439.html

If the old boy doesn't want to ship, I can pick them up for you and ship them to you (at your expense).
__________________
1967 337B
Flying in Skymasters since I was 16
Reply With Quote
  #5  
Unread 12-15-23, 11:24 AM
mshac's Avatar
mshac mshac is offline
Registered User
 
Join Date: Aug 2020
Location: North Texas
Posts: 763
mshac is on a distinguished road
I missed that being in a hurry. Thanks.

Here are some Continentals: 8 cylinders, 3 of which are chrome overhauls loaded and ready to go, one broken OH cylinder (use the parts to load another cylinder), the others are bare cylinders $1750 for everything: https://www.ebay.com/itm/255454370492

Says to "contact him for a better price" so I bet you could get it for $1500. If someone wanted to go in on something like this, I'd be a player. I'd love to have a spare OH sitting on the shelf. Turns out IO-360 and TSIO-360 use the same heads, same p/n and all.

Last edited by mshac : 12-15-23 at 11:28 AM.
Reply With Quote
  #6  
Unread 12-15-23, 11:33 AM
Frank Benvin's Avatar
Frank Benvin Frank Benvin is offline
Registered User
 
Join Date: Apr 2002
Location: CYCD
Posts: 336
Frank Benvin is an unknown quantity at this point
Make sure you get the right Cylinder for your engine

You can confirm using continetal's website by entering the part # of the cylinder to see if it fits or your engine information to get the part # of the cylinder for your engine

https://continental.aero/support/ill...s-catalog.aspx
__________________
1967 337B
Flying in Skymasters since I was 16

Last edited by Frank Benvin : 12-15-23 at 12:19 PM.
Reply With Quote
  #7  
Unread 12-15-23, 01:12 PM
mshac's Avatar
mshac mshac is offline
Registered User
 
Join Date: Aug 2020
Location: North Texas
Posts: 763
mshac is on a distinguished road
I certainly don't want to lead anyone astray, so here is the cylinder compatibility chart directly from Continental:

Name:  Continental 360 cylinder part numbers.JPG
Views: 2533
Size:  178.3 KB
Reply With Quote
  #8  
Unread 12-16-23, 01:01 PM
n86121's Avatar
n86121 n86121 is offline
bigcheese
 
Join Date: Nov 2003
Location: Potomac Airfield~!
Posts: 329
n86121 is on a distinguished road
The Plan

Thanks all for the leads.

I figured a cylinder for a TSIO 360AB3B would be readily available.

Oh boy, was I wrong.

Downside our on-field shop is also backing up.

So, if I could find a replacement and have on hand when old comes out, new one goes in fast.

Talking with the flight schools in the area, the supply is still badly amiss.
---

Years ago, before my rear engine OH, I would always go with new cylinders if needed.

Reasons being

A. A used OH cylinder might be physically identical, meet spec, but could already have 10,000 hours of thermal stress on it. Remember, mine is a turbo.

B. When it would come time to OH the engine, I would be using all my own first run cylinders, not things found and hoped for.

====

My options here became,

1. Major distributor, Air power, "No stock, new or used, hoping for restock late Jan or Feb"
Uh oh...

2. Nice shop in FL (Zephyr) "could overhaul it for around $1k,
but, shop floor is backed up 8-12 weeks before we could even get to it."

3. A nice chap in PA, Tim at Skyline Cylinders.

Once removed, mail the cylinder, turn around in just a few days.
Figure shipping back and forth 2-3 days each way,
Which inevitably wraps around a weekend, ...or two.

Since the valve is burnt (reason for all this suffering),
the new valve part alone would be ~ $500 + labor to clean it all up.
So maybe also $1k ish, and maybe 1-2 weeks to have back in hand.

Would it be officially 'overhauled,' or just valve replaced and shiny?
Not sure.

Nice option, but time of the essence to wrap it up "quickly"

Kept looking

4. J&J in PA had ONE new cylinder for this engine in stock, "can ship that day."

I bought it ($2.3k) and that's the one going on this week (?)

I will keep the cylinder coming off as spare, and OH it if/when I need one.

There's a 'lotta crap' has to come off the engine to get the #3 middle cylinder
Of course, you cant get it in/out without also loosening the one next to it,
Of course!
__________________
David Wartofsky
Potomac Airfield
10300 Glen Way
Fort Washington, MD 20744
Reply With Quote
  #9  
Unread 12-16-23, 02:09 PM
Frank Benvin's Avatar
Frank Benvin Frank Benvin is offline
Registered User
 
Join Date: Apr 2002
Location: CYCD
Posts: 336
Frank Benvin is an unknown quantity at this point
My mechanic has a new 658822A2 at his shop up here in Canada
__________________
1967 337B
Flying in Skymasters since I was 16
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 07:26 PM.


Powered by vBulletin® Version 3.6.9
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.