Notices
All Motor / Naturally Aspirated No power adders

rod bearing tolerance

Thread Tools
 
Search this Thread
 
Old 07-23-2014, 05:21 AM
  #1  
Honda-Tech Member
Thread Starter
 
blackeg's Avatar
 
Join Date: Feb 2003
Location: schooling kids in ny, usa
Posts: 9,813
Likes: 0
Received 9 Likes on 9 Posts
Default rod bearing tolerance

So ive been spec'ing out my lsvtec. With acl race hx bearings my rods are .0017-.0019. Mains with oem bearings are .0015-
0017.

Would you run rods that loose on a motor to daily drive and last a solid 50k miles? I know they are loose for nonvtec specs but fall on the high end of acceptable for itr
Old 07-23-2014, 06:05 AM
  #2  
moderator emeritus
 
98vtec's Avatar
 
Join Date: Oct 2002
Location: Cantonment, FL
Posts: 16,357
Likes: 0
Received 4 Likes on 4 Posts
Default Re: rod bearing tolerance

Originally Posted by blackeg
So ive been spec'ing out my lsvtec. With acl race hx bearings my rods are .0017-.0019. Mains with oem bearings are .0015-
0017.

Would you run rods that loose on a motor to daily drive and last a solid 50k miles? I know they are loose for nonvtec specs but fall on the high end of acceptable for itr

i would not call that "loose". Pending peak operating RPM, oil use..etc i would run that all day for a DD.
Old 07-23-2014, 11:36 AM
  #3  
Honda-Tech Member
Thread Starter
 
blackeg's Avatar
 
Join Date: Feb 2003
Location: schooling kids in ny, usa
Posts: 9,813
Likes: 0
Received 9 Likes on 9 Posts
Default Re: rod bearing tolerance

Originally Posted by 98vtec
i would not call that "loose". Pending peak operating RPM, oil use..etc i would run that all day for a DD.
itr valvesprings and cams, so ill probably wind up around 8400 for the limiter.

there were a few days last winter that were between -5 and -10 degrees f when i left for work in the morning...

i usually cheap out with oil, and just run castrol gtx changed every 3000 miles
Old 07-23-2014, 03:22 PM
  #4  
Honda-Tech Member
iTrader: (1)
 
1HGEJ2's Avatar
 
Join Date: Jan 2009
Location: Germany
Posts: 644
Likes: 0
Received 5 Likes on 5 Posts
Default Re: rod bearing tolerance

Specs are perfect..i would run it!
Old 07-23-2014, 06:13 PM
  #5  
Honda-Tech Member
iTrader: (2)
 
PSI GUY's Avatar
 
Join Date: Apr 2007
Location: Riverview, NB, Canada
Posts: 568
Likes: 0
Received 0 Likes on 0 Posts
Default Re: rod bearing tolerance

I try to keep all-motor clearances around 1.8 thou or so, boosted I've gone 2.5 without issue.
Old 07-24-2014, 04:43 AM
  #6  
Honda-Tech Member
Thread Starter
 
blackeg's Avatar
 
Join Date: Feb 2003
Location: schooling kids in ny, usa
Posts: 9,813
Likes: 0
Received 9 Likes on 9 Posts
Default Re: rod bearing tolerance

ok cool. thanks for the replies guys. i run my turbo motor around .002 for the rods, just wasn't sure about this one.
Old 07-24-2014, 01:09 PM
  #7  
Honda-Tech Member
 
d112crzy's Avatar
 
Join Date: May 2005
Location: Washington
Posts: 1,068
Likes: 0
Received 0 Likes on 0 Posts
Default Re: rod bearing tolerance

OT: Since when are oil clearances dictated by how the motor makes power?
Old 07-24-2014, 02:21 PM
  #8  
Honda-Tech Member
iTrader: (2)
 
PSI GUY's Avatar
 
Join Date: Apr 2007
Location: Riverview, NB, Canada
Posts: 568
Likes: 0
Received 0 Likes on 0 Posts
Default Re: rod bearing tolerance

Originally Posted by d112crzy
OT: Since when are oil clearances dictated by how the motor makes power?
Well most guys usually run a turbo engine looser as it makes more power.....and heat, much faster than an all motor. Rolling into the burnout box at idle to jumping on the two step into boost creates heat and expansion very quickly which is why it's built a bit looser. If the all motor car is a race only car, I would run it looser as well.

My personal preference only, but most people tend to go the same way.
Old 07-24-2014, 04:34 PM
  #9  
moderator emeritus
 
98vtec's Avatar
 
Join Date: Oct 2002
Location: Cantonment, FL
Posts: 16,357
Likes: 0
Received 4 Likes on 4 Posts
Default Re: rod bearing tolerance

Originally Posted by PSI GUY
Well most guys usually run a turbo engine looser as it makes more power.....and heat, much faster than an all motor. Rolling into the burnout box at idle to jumping on the two step into boost creates heat and expansion very quickly which is why it's built a bit looser. If the all motor car is a race only car, I would run it looser as well.

My personal preference only, but most people tend to go the same way.
Oil use (weight, viscosity etc) and RPM, IMO, are much larger factors in clearancing than the amount of power or aspiration.

Oil does a pretty good job at keeping the lower components from being so susceptible to combustion heat when in reality that combustion heat on a turbo engine is regulated by fuel and ignition timing just the same as naturally aspirated engines so heat through conduction really can't be much of a concern.

RPM is very hard on an engine which is why a given "race engine" with a couple thousand more operating rpm built within OEM tolerances is much more likely to have damage sooner than one that was built with the proper information in mind.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
karmaworks199
Forced Induction
8
10-15-2016 02:13 PM
SlowPokeEg
Honda Civic / Del Sol (1992 - 2000)
9
02-29-2012 09:08 AM
Muckman
Forced Induction
36
02-21-2012 10:08 AM
Fc_v8
Forced Induction
7
04-01-2010 11:20 PM
Mad Cow Disease
Tech / Misc
6
10-02-2003 01:55 PM



Quick Reply: rod bearing tolerance



All times are GMT -8. The time now is 11:35 PM.