VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.






VAF on Twitter:
@VansAirForceNet

  #21  
Old 10-02-2022, 07:22 PM
JDeanda JDeanda is offline
 
Join Date: Apr 2013
Location: Ventura, CA
Posts: 363
Default The Math

How does 1 part per 1000 = 1%?
Reply With Quote
  #22  
Old 10-03-2022, 06:24 AM
Dan 57's Avatar
Dan 57 Dan 57 is online now
 
Join Date: Sep 2018
Location: LSZF
Posts: 1,101
Default

Quote:
Dan: you had the stuck valve using mogas? i was under the impression that stuck valves are more a problem caused by leaded avgas.
Yes, I've had. And I also had it on a C-90 engine using only MOGAS as well.

Back to this one... checking compressions this Spring, I found 1 cylinder showing 0, nix. One of the exhaust valve was found almost impossible to move, all ok once the guide was reamed. And this was at 330h into the 400h of the SB388C...

Paul, yes I've seen your thread. As someone else commented, I doubt it will be conclusive in any way. I've had stuck exhaust valves on different engines, C-90/O-320/O-360, flying AVGAS or MOGAS or mixed, at different typical power settings.
One factor which most of us, inclusive myself, miss, is the material those valve guides are made of, the answer might be there...
__________________
- ain't the Destination, but the Journey -

www.aerofun.ch
YLL On Tour... the blook:
https://vansairforce.net/community/s...d.php?t=210564

RV-6.9 #25685, slider, O-360-A3A (carb/dual Lightspeed II), MTV-12-B, HB-YLL owner & lover
RV-4 #2062 HB-YVZ airframe builder

Last edited by Dan 57 : 10-03-2022 at 06:38 AM.
Reply With Quote
  #23  
Old 10-03-2022, 06:40 AM
rv8ch's Avatar
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 5,016
Default

Quote:
Originally Posted by Dan 57 View Post
...
One factor which most of us, inclusive myself, miss, is the material those valve guides are made of, the answer might be there...
Also, oil type, additives, and CHTs could be factors.
__________________
Mickey Coggins

http://www.rv8.ch/help-people-in-ukraine/
Reply With Quote
  #24  
Old 10-03-2022, 07:59 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 6,406
Default

Mickey is probably closer to the mark. Given Dan's experience, it's unlikely that lead is the cause. More likely oil is frying onto the stem or guide or both.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 460.7 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


Reply With Quote
  #25  
Old 10-03-2022, 08:14 AM
FlyinTiger FlyinTiger is online now
 
Join Date: Feb 2009
Location: Gilbert, SC
Posts: 350
Arrow Read Monaís STC instructions

My Mogas STC instructions for my old A65 powered Cub say to run one tank of leaded gas every 25 hours to add minimal lead to various parts of the engine. Any time running 100LL I add TCP.

Flying around the South East we donít have much pump mogas at airports and no UL fuel yet.

Looking forward to 93UL or 100UL coming to airports across the country!
__________________
AL
<><

Launching from SC45
Reply With Quote
  #26  
Old 10-03-2022, 08:55 AM
Dan 57's Avatar
Dan 57 Dan 57 is online now
 
Join Date: Sep 2018
Location: LSZF
Posts: 1,101
Default

Quote:
and CHTs could be factors
Yes, could be... the stuck valve cases I had were on different engines which I ran completely differently.

And if we take Marvel Oil, and other additives into account, and oil grade and the position of the stars, could be too...
I'm now heading towards the kitchen, luckily the machine's always plugged in
__________________
- ain't the Destination, but the Journey -

www.aerofun.ch
YLL On Tour... the blook:
https://vansairforce.net/community/s...d.php?t=210564

RV-6.9 #25685, slider, O-360-A3A (carb/dual Lightspeed II), MTV-12-B, HB-YLL owner & lover
RV-4 #2062 HB-YVZ airframe builder
Reply With Quote
  #27  
Old 10-03-2022, 11:28 AM
BoydBirchler BoydBirchler is offline
 
Join Date: Jul 2020
Location: Indianapolis
Posts: 196
Default

Why not use 2 cycle synthetic oil instead of Marvel Oil? It is made to be mixed with gas, lubricate everything in the engine and will not foul plugs. My airport golf cart runs well at 220 to 1...
Reply With Quote
  #28  
Old 10-03-2022, 11:49 AM
rv8ch's Avatar
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 5,016
Default

Amazingly on this month's "ask the A&Ps" podcast Mike Busch did recommend MMO for noisy lifters - perhaps it will help for stuck valves?
__________________
Mickey Coggins

http://www.rv8.ch/help-people-in-ukraine/

Last edited by rv8ch : 10-03-2022 at 12:00 PM. Reason: Corrected recommendation from stuck valves to noisy lifters
Reply With Quote
  #29  
Old 10-13-2022, 09:11 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 6,406
Default

In researching for another topic, I stumbled on to this document on the Conti website: http://continental.aero/xpublication...ives/si88-7-1/

Page 5 has some information on Mogas and valve seats. I'd question a couple of the statements made here but it still makes for interesting reading.

One does wonder if Lycoming and ECi seats are very different material though as the doom predicted here on a diet of Mogas doesn't seem to be taking out Lycoming seats. I think Pete Howell has over 2600 hours on his now...
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 460.7 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ



Last edited by rv6ejguy : 10-13-2022 at 09:22 PM.
Reply With Quote
  #30  
Old 10-14-2022, 11:21 AM
andoman andoman is offline
 
Join Date: Jul 2006
Location: Payson, AZ
Posts: 103
Default 2 Cycle Oil Flashpoints

Quote:
Originally Posted by BoydBirchler View Post
Why not use 2 cycle synthetic oil instead of Marvel Oil? It is made to be mixed with gas, lubricate everything in the engine and will not foul plugs. My airport golf cart runs well at 220 to 1...
Typical 2 stroke engines do not have valves. The oil added to the fuel is for bottom end lubrication.
2 stroke oil flashpoints vary from less than 200F to over 500F. Most are below traditional aircraft engine CHT normal operating range.
I’ve seen many 2 stroke oils leave very gummy and sticky deposits on exhaust port variable timing mechanisms in modern 2 stroke motorcycle engines.
Perhaps adding 2 stroke oil as a top end lubricant in an aircraft engine will greatly increase the possibility of sticking valves.
__________________
"The plane won't build itself..." RV-7A N7.62MM sold
-RV4 purchased. Extensive refurbishment complete. ďTakes off by itís self, flys hands off, lands by itís self...Ē
-HRII project: paint and panel to go!
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:00 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.