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.


Go Back   VAF Forums > Model Specific > RV-12/RV-12iS
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 09-29-2021, 09:17 AM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 203
Default

This is what I've read some where, it's because the oil filter has a by pass system in it in case of a clogged filter the unfiltered oil will now go into the engine, to prevent this the oil temp has to ne at least 120 F to be thin enough NOT to cause the by pass to open...I sincerely believe that no serious harm was done to the engine as long as the occurance did not happen right after starting and there was no warm up period or was done on an extremely cold day...call Lockwood Aviation, they are the resident experts on the Rotax.
Reply With Quote
  #22  
Old 09-29-2021, 03:04 PM
Azjulian Azjulian is offline
 
Join Date: Dec 2015
Location: Scottsdale, Arizona
Posts: 205
Default

There are threethings that I think your friend should check first in the engine.

1. the oil pressure at idle and at standard operating temperature should be within range, lower would indicate (in most cases) bearing wear etc.

2. if pressure is good then a differential compression test should be run

3. send away an oil sample to get an understanding of particles in the oil.

Those tests will give a basic understanding of engine health
Reply With Quote
  #23  
Old 09-29-2021, 03:22 PM
jnmeade jnmeade is offline
 
Join Date: Mar 2013
Location: Iowa
Posts: 185
Default

Quote:
Originally Posted by bobg56 View Post
call Lockwood Aviation, they are the resident experts on the Rotax.
They are AMONG the experts on Rotax. Also Brett Lawton at LEAF and Brian Carpenter at Rainbow Aviation. Also Ronny Smith in Mississippi.
Reply With Quote
  #24  
Old 09-29-2021, 06:52 PM
Moshonsk Moshonsk is offline
 
Join Date: Jul 2018
Location: Thunder Bay
Posts: 10
Default

Quote:
Originally Posted by bobg56 View Post
This is what I've read some where, it's because the oil filter has a by pass system in it in case of a clogged filter the unfiltered oil will now go into the engine, to prevent this the oil temp has to ne at least 120 F to be thin enough NOT to cause the by pass to open...I sincerely believe that no serious harm was done to the engine as long as the occurance did not happen right after starting and there was no warm up period or was done on an extremely cold day...call Lockwood Aviation, they are the resident experts on the Rotax.
I took the Rotax maintenance and service courses with Lockwood some years back and I can confirm the limitation is to prevent bypassing the filter when the oil is thicker whilst cold. It is mentioned somewhere in Rotax's documentation somewhere but I can't remember where.
Reply With Quote
  #25  
Old 09-29-2021, 11:05 PM
printbr printbr is offline
 
Join Date: Oct 2019
Location: Richland, WA
Posts: 68
Default

Quote:
Originally Posted by Moshonsk View Post
I took the Rotax maintenance and service courses with Lockwood some years back and I can confirm the limitation is to prevent bypassing the filter when the oil is thicker whilst cold. It is mentioned somewhere in Rotax's documentation somewhere but I can't remember where.
I took the Lockwood IRMT class as well and can confirm that this this the reason they give.
__________________
Bruce Rawlins
Richland, WA
LSRM-A
RV-12 Flying
Reply With Quote
  #26  
Old 09-30-2021, 02:00 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,564
Default

All this talk about the oil bypassing the filter when cold… Where is the harm in that? So, the oil bypasses the filter for a few minutes to improve circulation when oil is cold and engine is warming up. The oil is clean and filtered from previous flight. When the engine is warm the oil flows through the filter again. Sounds pretty good to me.

Consider old Continental A65-8 with just a course oil screen and no filter...
__________________
-
Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 750

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father - CFI) - USAAF 1st Lt. Captain B-17H
Reply With Quote
  #27  
Old 10-01-2021, 11:14 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,163
Default

I’ll take a stab at that, Jim. The oil pump is a positive displacement pump so flow rate through the pump is constant for a given RPM. If the bypass valve comes open that bypass flow is not going through the engine. While it may not be starving the bearings, it is definitely less flow than the design is intended to provide at that RPM.
Reply With Quote
  #28  
Old 10-02-2021, 03:07 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,564
Default

The internal oil filter bypass valve is designed to prevent damage to the spin-on filter itself. If oil flow through the filter element is restricted the bypass valve opens to prevent over-pressurization of the sheet metal filter housing and possible rupture. Oil is still flowing through the spin-on filter cartridge at the same rate only not through the filter media itself. Once the oil pump pressurizes the oil galleries in the engine it doesn’t matter if the oil filter element is being bypassed – oil is still flowing at the same volume to all lubrication points.

The oil pressure, typically 50 psig at cruise and normal operating temperature, is an indication of how well the sleave bearings are able to retain oil. Worn sleave bearings will flow more oil and thus pressure will be lower.
__________________
-
Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 750

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father - CFI) - USAAF 1st Lt. Captain B-17H
Reply With Quote
  #29  
Old 10-04-2021, 09:42 AM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,664
Default

Follow up -

I was away on vacation so didn't get involved in the discussion much.....

I will add my opinion that I doubt that one engine start over speed event did any damage that would cause it to start making unusual noises.

If is did, engines would regularly be being damaged because people do it all the time.

If there are new noises that aren't normal, I would be looking for a different cause.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
FAA/DAR
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #30  
Old 10-05-2021, 06:05 AM
thiggins thiggins is offline
 
Join Date: Mar 2020
Location: Saluda,NC
Posts: 46
Default

He was able to speak with a Rotax expert, who had him do some testing, pulling the engine through,… We think it’s ok. The rough running turned out to be some fouling of the front plugs we believe. All good.

Thanks for all the replies and info.

Tim
__________________
Donation 2021 paid
ASEL INST COMM Tail-wheeler
RV-12iS (Building wings, waiting for the fuse kit…)
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 01:39 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.