Subject: [Mg-t] Cast Iron block lip broken

From: [email-masked]
Date: Mon, 4 Mar 2013 10:02:15 -0500 (EST)

The oil pan lip on the engine block has one triangular piece broken in the  
bolt area.
 
Theoretically - the other bolts in the area will hold the pan in place and  
it has never leaked there since the previous rebuilder put massive amounts  
of Red- RTV on the gasket surfaces.
 
I would like to repair this section - but am afraid of damaging the cast  
block - anyone have experience doing this kind of work?
 
My solutions are three:
 
1.    Weld in thsi area - but this requires masive  amounts of preheat and 
high local heat - so I have nixed this solution.
 
2.    Fill in with brazing rod & retap - Brazing  material is softer and at 
lower temps then welding - but still required high  preheat and slow 
cooling - being that this area is on an outside lip - I do not  believe I will 
have much to worry about shrinkage creating a crack - since the  brazing 
material should strech enough not to create undue stress on the cast  iron.  The 
only problems are the preheat and cooling adn the hardening of  the cast 
iron.  
 
3.    USE J-B Weld and reinforcing it with steel screen  mesh and retapping 
- Drill 1/16" holes by 1/8" deep into the flange area  near the screw 
threads and at the flange edge.  J-B Weld 1/16" steel  rod into these areas to 
form the bases of support and strength.  Then cut  pieces of screen to fit and 
overlay the outside portion of the lip in the area -  then fill in with 
layers of J-B Weld and screen misture.  After retapping -  install a helicoil 
for the durability of the therads.
 
This area does not need to be supper strong or super stressed under a high  
torque value - the pan is very rigid and the purpose is only to screw in a 
bolt  to hold the gasket in place somehat tight.
 
Has anyone had to make such a repair?  Is J-B Weld a good strong resin  to 
use with cast iron? or is there a better resin?
 
Or just leave it alone?

 
 
Michael Balahutrak
53 - TD
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From: Gene Gillam <[email-masked]>
Date: Mon, 4 Mar 2013 18:05:04 -0600

Mike,

I have had a couple of blocks rewelded - one was cracked where the starter
bolts up and on the other the starter mounting bracket had broken all the way
off (thank you UPS).  Both times the welder preheated the area and then welded
ithe didn't seem to have any problems at all.

I've seen a number of blocks where the external water channel (behind the
exhaust manifold) that had been repaired by brazing - if you don't want to
weld repair the area I would opt for this over JB weld.

Gene

bolt area.
> Theoretically - the other bolts in the area will hold the pan in place and
it has never leaked there since the previous rebuilder put massive amounts of
Red- RTV on the gasket surfaces.
> 2.    Fill in with brazing rod & retap - Brazing material is softer and at
lower temps then welding - but still required high preheat and slow cooling -
being that this area is on an outside lip - I do not believe I will have much
to worry about shrinkage creating a crack - since the brazing material should
strech enough not to create undue stress on the cast iron.  The only problems
are the preheat and cooling adn the hardening of the cast iron.
>
> 3.    USE J-B Weld and reinforcing it with steel screen mesh and retapping -
Drill 1/16" holes by 1/8" deep into the flange area near the screw threads and
at the flange edge.  J-B Weld 1/16" steel rod into these areas to form the
bases of support and strength.  Then cut pieces of screen to fit and overlay
the outside portion of the lip in the area - then fill in with layers of J-B
Weld and screen misture.  After retapping - install a helicoil for the
durability of the therads.

[email-masked]