Connecting Rod Side Clearance Not In Spec. - Dodge Durango Forum and Dodge Dakota Forums
Register Home Forum Extras Website Features Timeslips Calendar Garage Auto Loans Search Today's Posts Mark Forums Read

Engine Modifications Intake Manifolds, Heads, Camshafts, Roller Rockers & Other Engine Parts.

Dakota-Durango.com is the premier Dodge Dakota Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools Rate Thread Display Modes
  #1  
Old 04-06-2010, 04:52 AM
Ricker97 Ricker97 is offline
Registered User
 
Join Date: Jan 2010
Location: Upstate N.Y.
Vehicle: 1997 Dodge Ram 1500
Posts: 48
Reputation: 10 Ricker97 is just getting started
Connecting Rod Side Clearance Not In Spec.

I started putting my motor (408) together and while checking the side clearance of the connecting rods that share the same bearing journal found it to be out of spec. when I checked it with feeler gauge between the two rods. The specs. should be .006" to .014", I have;
1&2 journal = .004"
3&4 journal = .008"
5&6 journal = .019"
7&8 journal = .020"

Any idea how to fix this?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 04-06-2010, 02:15 PM
9t9-5.2's Avatar
9t9-5.2 9t9-5.2 is offline
Home School Valedictorian
 
Join Date: Feb 2006
Location: I-O-WA
Vehicle: 9t9-5.2
Posts: 4,160
Reputation: 122 9t9-5.2 is just really nice9t9-5.2 is just really nice
To start with, are you sure the big end chamfer is oriented correctly. The large chamfer(the bearing and the rod) should be facing the crank, not the paired rod.
If all(rod & bearing chamfers) are OK the tight ones need to be machined to get the proper clearance. The loose ones, it has been a long time but IIRC typically .025-.028 is considered to loose by some people and need replaced. I have read about people running .030-.035 and claim to not have any problems. Some claim wider side clearance causes low oil pressure, others say it has no effect because oil pressure is determined by the rod bearing to rod journal clearance.

I will say I don't have a lot of experience here and am going by what I found years ago on the couple of builds I had done.
Keep us updated.
__________________
We've got no fear, no doubt, all in balls out

If every American cared enough to purchase one USA made garment per year the impact would be $9 billion. That is a lot of American jobs.
Reply With Quote Quick reply to this message
  #3  
Old 04-06-2010, 03:13 PM
Ricker97 Ricker97 is offline
Registered User
 
Join Date: Jan 2010
Location: Upstate N.Y.
Vehicle: 1997 Dodge Ram 1500
Posts: 48
Reputation: 10 Ricker97 is just getting started
Yes the chamfer is oriented the right way and all the bearings are chamfered for a radiused journal. I brought my mics home from work last night and mic'd the width of the rods large end. I would have thought that the tolerances of these Eagle H-Beam rods would have been alittle tighter. I got;

#1 .927" #2 .930"
#3 .927" #4 .928"
#5 .926" #6 .925"
#7 .925" #8 .925"

If I switched the highs and lows around, the rod side gap should be;
1&2 journal .009"
3&4 journal .011"
5&6 journal .016"
7&8 journal .015"

If I did this and this is what I came up with, would the .015" and .016" be ok. The spec. are .006" to .014"
Reply With Quote Quick reply to this message
  #4  
Old 04-06-2010, 03:58 PM
ScojoDak's Avatar
ScojoDak ScojoDak is offline
Dakota for Life!
 
Join Date: Sep 2004
Location: Kingman, Az
Vehicle: 98 Dakota R/T
Posts: 2,440
Reputation: 46 ScojoDak must have done something right
Scroll down to page 41 on this "How to hot rod a small block Mopar". BTW, I did some searches on the subject, and many run more clearance than you without issues. Also, It may not be the rods fault it doesn't fall into spec. Maybe the crankshaft grinder "kissed" the journal side a tad too much. Anyway... good luck and keep us posted.
__________________
Dakota for Life!

If you haven't lived for something, you'll die for nothing.


Reply With Quote Quick reply to this message
  #5  
Old 04-06-2010, 08:06 PM
9t9-5.2's Avatar
9t9-5.2 9t9-5.2 is offline
Home School Valedictorian
 
Join Date: Feb 2006
Location: I-O-WA
Vehicle: 9t9-5.2
Posts: 4,160
Reputation: 122 9t9-5.2 is just really nice9t9-5.2 is just really nice
Quote:
Originally Posted by Ricker97 View Post
Yes the chamfer is oriented the right way and all the bearings are chamfered for a radiused journal. I brought my mics home from work last night and mic'd the width of the rods large end. I would have thought that the tolerances of these Eagle H-Beam rods would have been alittle tighter. I got;

#1 .927" #2 .930"
#3 .927" #4 .928"
#5 .926" #6 .925"
#7 .925" #8 .925"

If I switched the highs and lows around, the rod side gap should be;
1&2 journal .009"
3&4 journal .011"
5&6 journal .016"
7&8 journal .015"

If I did this and this is what I came up with, would the .015" and .016" be ok. The spec. are .006" to .014"
The only thing I see with switching them around now is your rod and piston assembly's are probably weight matched and/or rotating assembly balanced as is. If they aren't, mix and match to get closer to what you need.
__________________
We've got no fear, no doubt, all in balls out

If every American cared enough to purchase one USA made garment per year the impact would be $9 billion. That is a lot of American jobs.
Reply With Quote Quick reply to this message
  #6  
Old 04-06-2010, 08:34 PM
moparman89's Avatar
moparman89 moparman89 is offline
Registered User
 
Join Date: Aug 2007
Location: Indy
Vehicle: '98 RC
Posts: 1,414
Reputation: 18 moparman89 is just getting started
Send a message via AIM to moparman89
0.008-0.0015 is optimal but 0.030 will run fine under say 7000rpm. It seems like Eagle has a tolerance of 3-4 thousandths, which kinda sucks, but I bet the crankshaft isnt perfect either.
Reply With Quote Quick reply to this message
  #7  
Old 04-09-2010, 02:30 PM
Ricker97 Ricker97 is offline
Registered User
 
Join Date: Jan 2010
Location: Upstate N.Y.
Vehicle: 1997 Dodge Ram 1500
Posts: 48
Reputation: 10 Ricker97 is just getting started
I picked up some new Clevite H Series rod bearings, swapped some piston/rod assemblies around and put everything together. The rod side gaps look alot better. Still at the high end of the specs. but from what everyones telling me alot of people run alot higher with no problems. These turned out to be;
1&2 journal .012"
3&4 journal .011"
5&6 journal .015"
7&8 journal .014"

Thanks everyone for all the great input, much appreciated...Rick
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Dodge Durango Forum and Dodge Dakota Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may post new threads
You may 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


All times are GMT +1. The time now is 09:59 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
Copyright 2001-2010 Dakota-Durango Archive