Welcome to the North American Subaru Impreza Owners Club Wednesday May 6, 2015
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

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.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 04-18-2002, 10:41 AM   #1
Rich10
Scooby Specialist
 
Member#: 14934
Join Date: Feb 2002
Chapter/Region: Tri-State
Location: Long Island
Vehicle:
2002 WRX
WRB

Default Pulley and engine damage

Can anyone mention a case in which a lightened or underdriven pulley caused engine damage on a Subaru boxer 4 engine?
* Registered users of the site do not see these ads.
Rich10 is offline   Reply With Quote
Old 04-18-2002, 11:22 AM   #2
live311
Scooby Newbie
 
Member#: 10801
Join Date: Oct 2001
Chapter/Region: NESIC
Location: Middletown, CT
Vehicle:
2008 Outback

Default

Maybe it threw the crank out of balance. Is your question hypothetical or did it really happen?
live311 is offline   Reply With Quote
Old 04-18-2002, 11:59 AM   #3
99OBSter
Scooby Newbie
 
Member#: 14324
Join Date: Jan 2002
Location: Dayton, OH
Vehicle:
1999 OBS 4eat
Silver

Default

I've never heard about any problems from properly installed pulleys, either lightened or underdrive. Now, if you don't tighten the retaining bolt for the crank pulley right, it can start to wobble and cause problems. That would be bad.
99OBSter is offline   Reply With Quote
Old 04-18-2002, 12:40 PM   #4
RaceCarRiot
Scooby Specialist
 
Member#: 6542
Join Date: May 2001
Chapter/Region: South East
Vehicle:
1997 Ver IV
silver

Default

lightened or underdriven pulleys usually cause problems on other cars, because the crank pulley incorporates a harmonic balancer...which a lightened one eliminates. the added vibration from removing the balancer can lead to premature crank bearing wear.

subarus don't have this problem because of the opposed engine layout.

i seem to be the only one experiencing any problem with my pulleys, but it's certainly nothing major...just annoying.

http://www.i-club.com/forums/showthr...hreadid=173962

-adam-
RaceCarRiot is offline   Reply With Quote
Old 04-18-2002, 12:46 PM   #5
Rich10
Scooby Specialist
 
Member#: 14934
Join Date: Feb 2002
Chapter/Region: Tri-State
Location: Long Island
Vehicle:
2002 WRX
WRB

Default

Quote:
Originally posted by live311
Maybe it threw the crank out of balance. Is your question hypothetical or did it really happen?
My question is hypothetical. I have read threads in which people warn of catastrophic engine failure from pulleys. I haven't heard of a single case in which this has occurred. I am trying to see if this is a problem.
Rich10 is offline   Reply With Quote
Old 04-18-2002, 01:41 PM   #6
tmat3
Scooby Specialist
 
Member#: 2817
Join Date: Nov 2000
Location: NYC and Troy, NY
Vehicle:
2001 Impreza 2.5RS
BRP

Default

On Miatas and BMWs, using aftermarket pulleys caused a load of problems. Miatas appearently have weak cranshaft design in the first place.

On our cars, because of the horizontally opposed engine layout, the vibration theoretically gets cancelled out. Also, unlike other 4 cylinder engines, the length of the cranshaft is shorter. Thus, the crankshaft is stronger.

That being said, there had to be a reason why Subaru decided to use a harmonic damper though. Probably as a safety measure.
tmat3 is offline   Reply With Quote
Old 04-18-2002, 05:43 PM   #7
obyone
Scooby Specialist
 
Member#: 16523
Join Date: Mar 2002
Chapter/Region: MWSOC
Location: Does anyone even read
Vehicle:
this anymore???

Default

Quote:
Originally posted by tmat3
On Miatas and BMWs, using aftermarket pulleys caused a load of problems. Miatas appearently have weak cranshaft design in the first place.

On our cars, because of the horizontally opposed engine layout, the vibration theoretically gets cancelled out. Also, unlike other 4 cylinder engines, the length of the cranshaft is shorter. Thus, the crankshaft is stronger.

That being said, there had to be a reason why Subaru decided to use a harmonic damper though. Probably as a safety measure.
Would make sense if you think about it....Subaru's logic was probably "Put a piece of rubber there, save on the lawsuit"

Last edited by obyone; 04-18-2002 at 06:02 PM.
obyone is offline   Reply With Quote
Old 04-18-2002, 06:41 PM   #8
RawCode
Scooby Specialist
 
Member#: 3115
Join Date: Dec 2000
Chapter/Region: AKIC
Location: Anchorage,AK USA
Vehicle:
2002 Impreza 2.5RS
Silver

Default

If you notice, it is a REALLY tiny peice of rubber...

RawCode
RawCode is offline   Reply With Quote
Old 04-18-2002, 07:38 PM   #9
Richard L.
Scooby Specialist
 
Member#: 8465
Join Date: Jul 2001
Chapter/Region: NWIC
Location: Puget Sound, WA
Vehicle:
'00 2.5RS Coupe, AW
'93 GMC Typhoon AWD

Default

Quote:
On our cars, because of the horizontally opposed engine layout, the vibration theoretically gets cancelled out.
Folks, vibration still exists in Subaru 4-cylinder horizontally opposed engine. To be specific, there are still free moments of 2nd order acting on the engine. On the other hand, in-line 6, horizontally opposed 6, and 60 V-12 engines are naturally and completely balanced because these do not have free forces and moments acting on them. So don't get overly confident. Yes, there is a reason why we have a harmonic damper.
Richard L. is offline   Reply With Quote
Old 04-18-2002, 10:43 PM   #10
Rich10
Scooby Specialist
 
Member#: 14934
Join Date: Feb 2002
Chapter/Region: Tri-State
Location: Long Island
Vehicle:
2002 WRX
WRB

Default

Quote:
Originally posted by Richard L.


Folks, vibration still exists in Subaru 4-cylinder horizontally opposed engine. To be specific, there are still free moments of 2nd order acting on the engine. On the other hand, in-line 6, horizontally opposed 6, and 60 V-12 engines are naturally and completely balanced because these do not have free forces and moments acting on them. So don't get overly confident. Yes, there is a reason why we have a harmonic damper.
I don't know why Subaru put the harmonic damper in the car. One explanation that I have heard is to help with NVH. I have asked my original question several times in several posts, "Can anyone mention a case in which a lightened or underdriven pulley caused engine damage on a Subaru boxer 4 engine?"

I have yet to hear of a single instance of damage to a Subaru horizontally opposed engine caused by a lightened or underdriven pulley.
Rich10 is offline   Reply With Quote
Old 04-19-2002, 11:23 AM   #11
maciek
Scooby Newbie
 
Member#: 11216
Join Date: Oct 2001
Location: Denver CO
Vehicle:
1991 SS 1998 BG
1996 BD

Default

I don't know if it is true, but I talked to a Subaru technician and he thought that the rubber piece on the stock pulley was mainly to take out vibrations from the belts.
maciek is offline   Reply With Quote
Old 04-19-2002, 12:45 PM   #12
Richard L.
Scooby Specialist
 
Member#: 8465
Join Date: Jul 2001
Chapter/Region: NWIC
Location: Puget Sound, WA
Vehicle:
'00 2.5RS Coupe, AW
'93 GMC Typhoon AWD

Default

Here is a very informative table from the Bosch Automotive Handbook, 5th Edition, posted by Jon [in CT] back in January 8th of 2002:



As you can see, there are free moments of 2nd order in all H-4 engines. You can learn more about this in a good college automotive engine design course.
Richard L. 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
3 gramlights 57 pro and 1 damaged one ! laruffa SCIC Private Classifieds 92 01-28-2010 10:30 PM
question about over revving and engine damage sburck Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 30 01-18-2009 10:35 AM
pulleys, pulleys and more pulleys msingell Transmission (AT/MT) & Driveline 5 12-22-2007 11:27 PM
High EGT's and engine damage Rich10 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 17 11-03-2003 09:37 PM
Pulley and engine damage Rich10 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 23 04-19-2002 05:56 PM


All times are GMT -4. The time now is 08:16 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2015 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.