VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 11-28-2016, 03:34 PM
DanH's Avatar
DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
Posts: 9,500
Default To Hone or Not To Hone?

In another thread, a respected individual commented "Normal practice, anytime the piston comes out if the cylinder, and especially when new rings are used, is to hone the cylinder as well."

Honing when installing new rings is obvious enough.

However, consider pulling a jug for any sort of inspection, finding nothing out of the ordinary, and re-installing it over the same rings and piston.

Why would it be necessary to hone? Please be specific.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #2  
Old 11-28-2016, 04:20 PM
Weasel's Avatar
Weasel Weasel is offline
 
Join Date: Dec 2012
Location: Brooksville, MS
Posts: 745
Default

Recently I had a conversation with Continental Motors Inc. specifically on this.

They had a discussion about it with the cyl shop specialists and said that if the rings are already well seated and there is no problems with the rings or cyl, there is a better chance of it maintain a good ring seal by re-using the existing rings than to re-hone and start again with new rings.

I would be very interested in hearing a full explanation of how they arrived at this conclusion and any data they have to support it. It is sort of a surprise to me, but I am sure they know a lot more than me about the results of each scenario.
__________________
Weasel
RV-4 715hr Sold
RV-10 "School Bus" - +1600hr counting
Fisher Classic Cassler Power VW sold
RV-10 N7631T 820hr Sold
RV-8 700+hrs
Carbon Cub 200 hr Sold
One-Off Super Cub 100 hr
SERFI AWARDS

http://weaselrv10.blogspot.com/
Reply With Quote
  #3  
Old 11-28-2016, 04:29 PM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 5,516
Default

Quote:
Originally Posted by DanH View Post
In another thread, a respected individual commented "Normal practice, anytime the piston comes out if the cylinder, and especially when new rings are used, is to hone the cylinder as well."

Honing when installing new rings is obvious enough.

However, consider pulling a jug for any sort of inspection, finding nothing out of the ordinary, and re-installing it over the same rings and piston.

Why would it be necessary to hone? Please be specific.
I can not think of a single reason.
__________________
Bill

RV-7
Lord Kelvin:
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”
Reply With Quote
  #4  
Old 11-28-2016, 04:33 PM
Cayugarandy Cayugarandy is offline
 
Join Date: Jan 2015
Location: Newfield NY
Posts: 13
Default Honing

I've always wondered why the 'accepted' practice was that if the rings came out of the cylinder that they must be replaced and a hone done.I know its not a Lycosaurus,but in Rotax engine school taught by Eric Tucker we were taught to disassemble the rings from the piston,clean out carbon,measure ring side clearance and end gap,and if within the much tighter specs than Lycosaurus,reinstall in an unhoned cylinder.I've done it many times in various engines and it has worked well.Why not in a Lycoming?
Randy Tubbs A+P
RV8 180hp
Reply With Quote
  #5  
Old 11-28-2016, 04:52 PM
maniago's Avatar
maniago maniago is offline
 
Join Date: Aug 2014
Location: Bowie MD
Posts: 886
Default Hold over

Thats a holdover from automotive days of yore. Cost effective preventative mx. Why? 'Cause pistons come out the top and any ridge broke a ring usually, iron rings were (and still are for those motors) cheap, honing was done with a drill in the garage, along with a said ridge ream.

In general tho, I also dont see how it applies for a Lyco or any jug style motor (ie HD, VW, Corvair etc) without due cause.

Dont fix what aint broke.

That said, ever seen a cylinder bore without thrust line scratches?
__________________
Mani
Busby MustangII (FoldingWing) Pending DAR.
Don't be a hater; I'm a cousin with thin wings!
N251Y (res)

Last edited by maniago : 11-28-2016 at 04:54 PM.
Reply With Quote
  #6  
Old 11-28-2016, 05:20 PM
Raymo's Avatar
Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 2,189
Default

I see it as an inspect and repair as needed (IRAN). It will depend on time, wear and type of use. Each case is unique.

If one or more ring has broken, I think it makes sense to hone prior to installing new. Having read the other thread, measurements should be made to ensure the cylinders are within limits, along with other wear parts.
__________________
Ray
RV-7A - Slider - N495KL - First flt 27 Jan 17
O-360-A4M w/ AFP FM-150 FI, Dual PMags, Vetterman Trombone Exh, SkyTech starter, BandC Alt (PP failed after 226 hrs)
Catto 3 blade NLE, FlightLines Interior, James cowl, plenum & intake, Anti-Splat -14 seat mod and nose gear support
All lines by TSFlightLines (aka Hoser)
Reply With Quote
  #7  
Old 11-28-2016, 05:32 PM
N258RE N258RE is offline
 
Join Date: Apr 2006
Location: MI
Posts: 59
Default

what about channel chrome cylinders? hone? no hone?

I never could find a definitive answer
__________________
RV-8
flying
Reply With Quote
  #8  
Old 11-28-2016, 06:05 PM
cajunwings cajunwings is offline
 
Join Date: Jun 2007
Location: new iberia la
Posts: 768
Default Honing

I have removed and reinstalled cylinders many times without replacing rings or honing if all other parameters were good. In the case of a cylinder with 1000 or more hrs it always got honing, new rings, a valve & guide inspection and a new exhaust valve if the customer was willing.

Don Broussard A&P, IA

RV-9 Rebuild in Progress

57 Pacer
Reply With Quote
  #9  
Old 11-28-2016, 07:19 PM
Canadian_JOY Canadian_JOY is offline
 
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,291
Default

What a terrific discussion topic!

My experience has always been to follow that "if the rings leave the cylinder bore, replace them and hone the cylinder" rule. This has been done, not because of any good science, but more because of folklore.

What I wonder is, if the piston has been removed from the cylinder bore, how does one ensure that each little groove that has been wear-machined between the rings and cylinder walls is re-aligned when the piston is re-inserted into the cylinder? I know that when I've removed pistons the rings have always had a chance to shift around a bit, so even if the conn rod / wrist pin holds the piston in the same rotational plane, the same can't necessarily be said for the rings. Is this at all an important consideration (beyond the obvious concern about ring gaps not aligning)?
Reply With Quote
  #10  
Old 11-28-2016, 07:36 PM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 2,573
Default

Just wondering outloud.
Just because a ring set is well-seated, does that mean that if it is turned some on the piston before reassembly, it will still be well-seated?

Is it important, if you are going to keep the old rings and not hone, to be sure to maintain the clock-position of the rings on the piston, so they go back in close to the same orientation as where they came out?

Or, are the wear surfaces of the rings happy enough to mate to new areas of the cylinder?

Ha! Canadian_JOY beat me to it with the same question.
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 625
LS6-15/18W sailplane SOLD
bought my old LS6-A back!!
VAF donation Jan 2020
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 12:31 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.