I was going there next, compression check to determine if the head is doing it.
One does not take switching heads nowadays as lightly as before, too many variables crop up. Like did the head come with cams? If not then likely however the valve takeup was done may be at fault there. You don't just switch cams at the drop of a hat any more, the valves often need a set or if hydraulic then the lifters may not have been bled down and one is holding a valve open to slightly miss.
|