Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC General > Newbies & FAQs

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 03-02-2003, 11:58 PM   #1
RhinoRex
Scooby Newbie
 
Member#: 29825
Join Date: Nov 2002
Location: Rochester, Illinois
Vehicle:
2002 WRX Wagon
WR Blue

Question Uneven piston wear in flat fours?

It seems to me that the flat four has the potential for worse engine wear than other engine configurations. As you all know, a good deal of engine wear happens when you first start up. In a flat four, you would always have the pistons' weight resting on the same side of the rubber piston rings. I would think that one side of the ring (the down side) would wear faster than the other sides. In general it seems like gravity would cause problems in flat fours that inline engines don't face and that Vs face much less.

I'm sure there's a way that this is deal with. How do they do it?

For those of you who have rebuilt horizontally opposed engines, do you notice uneven wear on the rings?
* Registered users of the site do not see these ads.
RhinoRex is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 03-03-2003, 12:27 AM   #2
Gethin
Scooby Specialist
 
Member#: 2998
Join Date: Nov 2000
Chapter/Region: VIC
Location: BC
Vehicle:
2002 WRX
WRB

Default

The engine has bee in development for over 30 years and is one of the most reliable designs you will see.

The pistone design is very light and IMHO the gravity effect would be negligable.

http://www.mypersonaldrive.com/Subar...ton-Cranky.asp

I have seen pictures before of engines stripped down and never seen any wear as you describe resulting from the gravity effect on cold start.

Anyone else had hands on experience examining the bores?

Gethin.
Gethin is offline   Reply With Quote
Old 03-03-2003, 01:05 AM   #3
philip_g
Scooby Specialist
 
Member#: 32906
Join Date: Feb 2003
Location: Castle Rock CO
Default

Quote:
Originally posted by Gethin
The engine has bee in development for over 30 years and is one of the most reliable designs you will see.
more like 60+ if you include light airplane engines, which really haven't changed in over 50 years
philip_g is offline   Reply With Quote
Old 03-03-2003, 10:01 AM   #4
RhinoRex
Scooby Newbie
 
Member#: 29825
Join Date: Nov 2002
Location: Rochester, Illinois
Vehicle:
2002 WRX Wagon
WR Blue

Default

I am not at all questioning the reliability of the flat four. It's more that this problem occurred to me and I am now curious about how they solved this engineering challenge.

That is, this question is more curiosity than heresy.
RhinoRex is offline   Reply With Quote
Old 03-03-2003, 10:14 AM   #5
Eric SS
Sooby Guru
 
Member#: 1914
Join Date: Jul 2000
Chapter/Region: SWIC
Location: 2014 Q60S, 2016 Chevy SS
Vehicle:
2000 2.5RS w/ EJ22T
swap and N20. gone. : (

Default

There is more than enough oil in the cylinders at startup to prevent uneven wear.

What are you talking about when yo usay "Rubber piston rings"???
Eric SS is offline   Reply With Quote
Old 03-03-2003, 12:08 PM   #6
RhinoRex
Scooby Newbie
 
Member#: 29825
Join Date: Nov 2002
Location: Rochester, Illinois
Vehicle:
2002 WRX Wagon
WR Blue

Default

When I wrote that, I was thinking of the compression rings and the oil control ring. I knew as I wrote it that they aren't made of rubber, but I figured that people would know what I meant.

Thanks to the link that Gethin posted, it seems that the piston skirt is more relevant to what I was thinking of.

That article is pretty interesting.

So is that the answer? There's enough oil left in the cylinders and gravity introduces no special issues? Naively (which is the only way I operate in engineering) if I imagine moving an object back and forth inside a horizontal cylinder by hand and then up and down in a vertical cylinder, it seems like there would be more friction in the horizontal.
RhinoRex is offline   Reply With Quote
Old 03-03-2003, 12:56 PM   #7
Eric SS
Sooby Guru
 
Member#: 1914
Join Date: Jul 2000
Chapter/Region: SWIC
Location: 2014 Q60S, 2016 Chevy SS
Vehicle:
2000 2.5RS w/ EJ22T
swap and N20. gone. : (

Default

Quote:
Originally posted by RhinoRex
When I wrote that, I was thinking of the compression rings and the oil control ring. I knew as I wrote it that they aren't made of rubber, but I figured that people would know what I meant.

Thanks to the link that Gethin posted, it seems that the piston skirt is more relevant to what I was thinking of.

That article is pretty interesting.

So is that the answer? There's enough oil left in the cylinders and gravity introduces no special issues? Naively (which is the only way I operate in engineering) if I imagine moving an object back and forth inside a horizontal cylinder by hand and then up and down in a vertical cylinder, it seems like there would be more friction in the horizontal.
The parts are light enough for gravity to not have much effect compared to the outward force the rings are putting on the bore.
Eric SS is offline   Reply With Quote
Old 03-03-2003, 01:21 PM   #8
North Ursalia
Miss You Mom
Oct 1940 - Feb 2008

Super Moderator
 
Member#: 809
Join Date: Jan 2000
Chapter/Region: NESIC
Location: NH, Land Of Many Trees
Vehicle:
2000 2.5 RS, '14 For
92 5MT SVX

Default

Indeed... the pistons weight about a pound with rings.


Brian
http://www.subaruwrxparts.com
http://www.wrxstiparts.com
http://www.subarubajaparts.com
North Ursalia is offline   Reply With Quote
Old 03-03-2003, 10:38 PM   #9
Gethin
Scooby Specialist
 
Member#: 2998
Join Date: Nov 2000
Chapter/Region: VIC
Location: BC
Vehicle:
2002 WRX
WRB

Talking

Yikes! One pound! The Scooby Engineers did a great job!

Gethin.
Gethin is offline   Reply With Quote
Old 03-04-2003, 12:02 AM   #10
gjhsu
Scooby Guru
 
Member#: 12329
Join Date: Nov 2001
Chapter/Region: TXIC
Location: Austin, TX
Vehicle:
2o15 WRX
Ice Silver

Default

Quote:
Originally posted by RhinoRex
if I imagine moving an object back and forth inside a horizontal cylinder by hand and then up and down in a vertical cylinder, it seems like there would be more friction in the horizontal.
Also consider that the bore and piston are made to pretty exact tolerances, so the friction cause by weight should be darn near even throughout the circular shape. I could imagine your problem if there was any sort of gap between the top of the piston and the cylinder, but I think they are manufactured tight enough to avoid that problem. For the record, I'm no mechanical engineer, but that's just what I am observing.
gjhsu is offline   Reply With Quote
Reply

Thread Tools
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

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Help! Uneven Rotor Wear with new rotors (H6 in rear) and pads Saucy7 Brakes, Steering & Suspension 6 10-07-2008 03:23 PM
uneven tire wear - is this normal? driver8 Brakes, Steering & Suspension 5 06-22-2002 05:02 PM
Uneven tire wear question: bad alignment by Subaru? Kaiser Brakes, Steering & Suspension 11 02-27-2002 10:40 AM
Uneven tire wear and AWD... Layman Brakes, Steering & Suspension 7 07-05-2001 06:50 PM
Uneven tire wear... strange... jasony Brakes, Steering & Suspension 7 07-02-2001 01:20 PM

All times are GMT -4. The time now is 08:56 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.