Has anyone gone into the head to change the aux intake valve? Any pointers in taking the head apart? Putting it back together? It looks like I'm going to take a stab at it & it would be nice to have some idea before I start. Thanks, Rob (take out the nospam, I'll see if the mailbox has any room left since the last time I put that address on a newsgroup)
The valves are commonly rebuilt as the o-rings around the valve body fail. This causes an oil leak that fouls out the spark plug. The first thing to do is to get your self a slide hammer and the special auxiliary valve pulling attachment which, if I remember correctly, is made by Assenmacher Specialty Tools (AST) (I wasn't able to find a link but I'm sure that your neighborhood SnapOn dealer could get one for you). Once you've acquired the proper puller you then remove the rocker arm assembly and the 22 mm locknuts that hold the valve bodies in place. Clamp the puller attachment onto the valve and pull it out with the slide hammer. The AST puller holds onto the valve and keeps the slide hammer aligned with the valve thereby greatly minimizing any chance of bending the small diameter auxiliary valve. The next trick is to remove the copper washers in the bottom of the valve body bore in the head. I've found that this is best done with a right angle hook tool such as http://tinyurl.com/3766a though you do have to be very careful that you don't scratch the bore (note that there are two copper rings per valve - one on each side of the valve body). Clean out the bores, replace the copper seal rings, clean the valves (which by the way can be disassembled without tools and there's usually no need to reface them), install new o-rings on the valve bodies giving them a light coat of Sylglide silicone grease, torque down the locknuts, and replace the rocker arm assembly watching the rocker arms carefully so that you make sure that you don't bend any valves. Lastly, readjust the valves and reseal the valve cover. By the way, don't forget to put some ultra grey silicone under the corners of the rocker arm towers at the far end of the head, on the distributor carrier o-ring, and on the cam seal or you run the risk of developing an oil leak. You may also need to clean the spark plugs since a bunch of oil tends to get down into the precombustion chamber. See the factory service manual available at http://www.helminc.com for further info, e.g., torque specs and etc. Eric