Date: Sun, 6 Apr 2003 11:37:03 -0400
Reply-To: Robert Donalds <bostneng@FCL-US.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Donalds <bostneng@FCL-US.NET>
Subject: Re: New versus Welded Heads?
Content-Type: text/plain; charset="iso-8859-1"
I have spent allot of time trying to repair OEM WBX heads. The OEM heads crack between the seats and these cracks can extend down into the intake and the exhaust ports they also crack around the upper outer head bolt holes. These cracks can and often do reach the water jacket I have had this happen more than once on heads I have removed the seats and welded these same cracks reappear within a few hundred miles. Years ago I came to the conclusion that the OEM heads have a limited life span and that they should not be put back in service when they are removed and are in need of welding. I ask my customers do you want to work on it or drive it????? All my rebuilt engines have AMC heads with upgraded valves and OEM retainers
The Spanish AMC WBX heads are a better casting and a better alloy than stock OEM heads they don't crack in the ports or at the head bolt holes they also don't have the corrosion problems at the water jacket sealing surface to the extent that the stock heads do. I have seen the AMC heads crack between the seats but this does not lead to any other problems I have observed. All my vans have used AMC heads on them that have been repaired by grinding, welding and milling the water jacket sealing surface.
The down side of the new AMC heads is the quality of the valves the importer Marnel installs in the heads and I personally would like to see a harder valve seat used as well. I use the AMC heads for my big valve engines. To do this I remove the seats and counter bore the seat hole so I can install a harder valve seat with a larger outer diameter and a stock inner diameter This allows me to use a 3 MM larger valve and with a custom valve job this makes the air flow around the valve with a gain in flow of 20% threw out the valve lift. I have a chart of flow bench results on my web page at the listing for the stage three engine. The intake and exhaust ports need only minor blending and the gasket surfaces can be matched to eliminate any edges that would increase turbulence
so if you use a used or rebuilt OEM head you have to ask yourself ARE YOU FEELING LUCKY
Bob Donalds
http://www.bostonengine.com
all rights reserved
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