2.8 Head Water Passage Modifications

[Beamin]

I‘ve got an exhaust leak along the bottom of the header that I can’t seal up. Before reinstalling the motor, I should have pulled the heads and done DanRs modifications plugging the emission ports along the bottom of the head and drilling for the additional header bolts but I was overly optimistic that it wasn’t an issue before I pulled the motor, so everything should be fine putting it back together. Anyway, I‘ve pulled the heads and will be heading to my machine shop tomorrow to have the work done.

While the heads are off, I want to drill the additional cooling passages that I keep reading about, but I keep coming across different info. Some recommend just two additional holes. Some say drill all four. Seems like more holes = more cooling. Is there any reason NOT to drill all four holes in each head?

 

[DanR]

Andy, I can send you the info on how I do them, (same as recommended by Sven P).

E-mail me

 

[Beamin]

Andy, I can send you the info on how I do them, (same as recommended by Sven P).

E-mail me

Thanks Dan, email sent.

 

[absunbeam]

Followed the recommendation in Dan’s V6 instruction. Found the casting cavity is offset on the lower drilling and just catches it. Should help in keeping a cooler head.
Plugging the exhaust holes and milling them off will keep things quiet. Eliminating all for the smog equipment which kept the heads hot and eventually cracks them helps.

 

[Beamin]

Water passages are drilled. Love the information on this site. Found a picture of a head that someone cut in half showing the water passages, which made it easy to figure out which way to angle the bit on the lower passages.

Plugged the exhaust holes, ground flat, then drilled and tapped for the lower header bolts as per Dan’s recommendations.

Time to put it all back together. Does anyone know the proper torque sequence and specs? Google search turns up various torque values.

 

[absunbeam]

This is from the Haynes manual.