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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: fairweather on September 09, 2009, 09:29:42 pm
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Trying to get some specifications to match up on a 1Z head is proving confusing. The Bentley doesn't provide a spec for valve protrusion/recession relative to the head surface, should they protrude or be recessed, does it matter as long as the recession below the valve cover rail is at spec?
In order to get the measurement A, section 15a-18, figure 20 in Bentley the valves will end up being recessed in the head, currently all of them protrude to what seem like widely varying degrees (see picture).
For ex. on the farthest to the right, in order to get the valve cover rail to top of valve stem distance to be correct the valve will end up being recessed by .021" whereas it is currently is protruding by .019".
How is the preload for the lifter/cam measured after all this is done?
Any clarification is appreciated.
Tom
(http://www.vanagonaccessories.com/head1.jpg)
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what are you doing? have you changed the seats? they do stick out normaly, as long as they dont hit pistons and seat properly then i think ur in business, i dont see why you need to worry so much?
if your still worried you can get them skimmed flat to the head, it will lower ur CR a bit, sum peeps think it will burn the valves but it wont
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It just bothered me and my machinist that they were so variable and the Bentley is lacking in specs. We ended up bringing them all down to the lowest one on the left, after the valve job they ended up being .008" recessed. I've got about 500 miles on it now and all seems well.