In the process of rebuilding the head, I noticed that there is play in the exhaust valves. Pulled out into the open position, the valve can be moved about .010" .
I think the guide to stem clearance is supposed to be .002" but I do not know how to measure that directly. I just see that the exhaust valves ‘wiggle’ but the inlet valves only minimally.
Does that mean I need to replace my guides? Hate the thought of having to rev up the BBQ to heat up the head, press them out, and warp the head in the process.
Your collective pearls of wisdom will be much appreciated.
Vlad
67 series 1 DHC
You likely need to replace guides and valves. I just did this and a 60K mile 4.2. Used 2 hot plates to heat head for 30 minutes. When thermal gun indicated ~200F I used a threaded rod and reduced size nut to pull the guides. I was nervous but all went well. Instillation of the new guides is another story. The shop that ground the seats for me also skinned the head .010".
Vlad it’s possible that a machine shop can install inserts in your guides, a route I prefer if it’s the first time around for the original guides. Removing and installing guides isn’t a freebie, it often pulls aluminum out - enough to require you to go to oversize guides.
According to the Jag manual - the fat green book - it calls for installing the next oversize guide after removing the original. They reference grooves that are machined into the guides to identify their original diameter. “Use guide with 2 grooves to replace original with one groove…” and so on. Is this correct???
Maybe correct, depending on who made the valve guides. Best to measure what you have, after you pull the guides. I did use the first oversize. They measured .504" OD. I heated the head, had the new guides in the freezer, quickly greased the holes and guides then drove them in with a homeaid pilot. Used big hammer to drive them in. Thud…thud…thud…TING. It was obvious when they hit the retaining ring. They went in quite tight… The biggest PITA was removing and installing the C retaining ring. If you have not done this before, I suggest you let the machine shop do it, just be sure they speak XK head. A valve job will be needed when new guides and valves are installed which of course disturbed all the tappet clearances. Getting the shims all adjusted will take some time, skill and patience.
