Re-Tapping a 3.0L Evinrude main bearing

[ggodwin]

Hey folks,
im just going to skip how this has happened.

I need to re-tap the threads of a main bearing in my block. What are my options?

1.) Re-Tap with a larger bolt?
2.) Insert a Heli-Coil?
3.) other

This bolt does not have a lot of wall thickness to work with. Fortunately it doesn’t seem to require much torque to hold this in place.

 

[racerone]

Helicoil----How did this go bad I want to know ?

 

[Joe Reeves]

Restore to original threads... "Heli Coil"... the design with the most threads.

 

[ggodwin]

I’m not sure. I won’t know until I confirm all the other threads. I don’t know if it is something that I did or if it was the previous builder. It was a fresh rebuilt that lost a ring pin. Destroyed a the sleeve in number three. I had it re-sleeved and put it back together. If it was something I did then it’ll effect all others also. I *did* get toque here. But after I backed the bolt out I could never get torque again. It was like I just got enough to reach torque but damaged the threads.

I did all bolts at three different torque values. I think they were this.

16 ft/lbs
25 ft/lbs
35 ft/lbs

one of the bolts has been replaced and is a large Allen bolt.

 

[ggodwin]

Does anyone know the size of this bearing bolt that holds these cases together? I’m not home and want to look for the proper heli-coil.

 

[ggodwin]

I’m pretty sure that I messed by not putting a die on my bolts and cleaning them up before re-installing them. It took some effort to get a 7/16x14 die on it to clean it up.

 

[racerone]

What size are the other main bearing bolts ?-----3/8 -NC perhaps ?

 

[Faztbullet]

Make sure you replace all pistons a if one has lost a pin others are soon to follow. Also did you have the cooling mod done?

 

[boobie]

Fatz, what is the cooling mod you mentioned ??

 

[Faztbullet]

Open deck blocks rarely loose locating pins it the closed deck that have the problems. The cooling mod is to drill and add deflectors and enlarge hole under rect/reg,sort of like the Ficht cooling setup. Many people will repair the damaged cylinder and piston but don't realize the heat has effected the others and locating pins shifted in piston, then there is another failure. Thats why if you have one piston fail you replace all of them no matter how good they look. Also a Keensert will be a better fix than a Helicoil..

 

[boobie]

Thank You, Boobie.