Cracked Rear Main Cap - Need Advice - JeepForum.com

 
LinkBack Thread Tools
post #1 of 5 Old 06-17-2017, 02:16 PM Thread Starter
tjs2010
Registered User
2001 TJ Wrangler 
 
Join Date: Oct 2010
Location: Bethpage NY
Posts: 36
Cracked Rear Main Cap - Need Advice

Hi All,

This question is not jeep specific, but I am sure there are some good motor heads on here that can offer advice on an outside build. I am currently working on a complete restore of a '73 Triumph TR6. I received the block back from the shop to begin reassembly and in going through my parts realized my Rear Main Bearing Cap is cracked. I am not sure if it happened when the previous owner had it or when I was disassembling. The issue is this is not a part that can be easily replaced. The only replacement parts available are a full set of CNC aftermarkets running for $500 for the set!!!! Other replacement option would be to pick up a cheap block for $400 to get the cap, but then paying a shop to line hone I end up past the point of the CNC ones - realizing those too would also need to be line honed as well. That said, looking at the crack I want advice on the below as possible options:

1. I find a shop to CNC me a replacement and hopefully save some cash over the full set. Anyone out there on Long Island capable of doing this?

2. Can this be spot welded?!

3. Or where I am potentially leaning towards - can I leave it as is? Given the location of the crack and how the bolt passes through both pieces would the 55ft lb of torque suffice to ensure proper seal? When bolted down as is, and checked with plasti I am still well in range for my recommended clearance.

Pictures below.

Thanks

Attached Thumbnails
IMAG1594.jpg   IMAG1593.jpg  

2001 TJ - "The Toy" - Basically stoc at this point. 4.0 Auto

2013 Grand Cherokee TrailHawk
tjs2010 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 06-19-2017, 07:20 AM Thread Starter
tjs2010
Registered User
2001 TJ Wrangler 
 
Join Date: Oct 2010
Location: Bethpage NY
Posts: 36
bump! anyone have some advice to offer?

2001 TJ - "The Toy" - Basically stoc at this point. 4.0 Auto

2013 Grand Cherokee TrailHawk
tjs2010 is offline  
post #3 of 5 Old 06-19-2017, 10:11 AM
Kruzin
Web Wheeler
 
Kruzin's Avatar
2009 JK Wrangler 
 
Join Date: Aug 2007
Location: Lakewood
Posts: 4,322
I certainly wouldn't use that cap. The crack is only going to grow until it's all the way through, at which time it will crack the bearing and trash the crankshaft.
I wouldn't trust welding it either. That could warp the whole cap slightly, then it just won't fit right. Might bolt on, but doubt the bearing would be perfectly square.
I'd start making calls to CnC shops or looking for a used engine you can scavenge from.

'09 JK Rubicon
'01 XJ Sport
'10 Fusion
Kruzin is offline  
 
post #4 of 5 Old 06-19-2017, 01:22 PM
222Doc
Web Wheeler
 
222Doc's Avatar
2012 JK Wrangler 
 
Join Date: Sep 2011
Location: Lake Havasu City
Posts: 7,103
Garage
I agree^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

But if i had to weld that. first off only if it was forged not cast. I would weld it on the block torqued to specs or a fixture and would even pre heat it just so it dont get a odd warp as you burn it in. but first after torquing that down i would grind into the crack as best one can to get better penetration. then weld it and peen the welds. hope for the best but that is a Macgyver fix really.

Home of the Parker Desert Splash

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
222Doc is offline  
post #5 of 5 Old 06-19-2017, 06:37 PM
rjbruzan
Moderator
2004 TJ Wrangler 
 
Join Date: May 2008
Location: Lake in the Hills
Posts: 2,725
I would not want to run it but I might. What does the machine shop say? It will be in compression and may have been like this since new?

Of all the things Ive lost
The one I miss most is my mind

Its like a fart in a windstorm
It smells good but thats about it

Registered Six Offender
Home of the Buzzin Half Dozen
rjbruzan is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



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
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome