MVA Heads at 15K, 120R
I have been getting more and more of these coming through but they are mostly new. Now I got a set of MVAs here with 15k on them.
What I found:
Guide wear and oil passing on the exhaust stems. The exhaust valves will not return to the seat unless they are not turned from the original positions when maneuvered by hand without springs. The last 1/2" of the guide, port side, has baked carbon and valves show the same. There is a noticeable trough worn in the top of the exhaust stems. Both front and rear are equally affected.
IMHO these exhausts were headed for seizing, same as the 07 CVO original pre-program heads do. These will be fixed with AV&V bronze manganese guides, .0014 in & .0016" clearance ex and high quality viton seals. Clearances now are .0019-.0024".
Stem seals are K-line.