Posted by Ken C. on Wednesday, May 16, 2007 at 21:26:10 :
I'm rebuilding the 318LA transplant that is in my '64 W200. Everything looks good internally, still has the original bearings with perfectly worn surfaces .. no scratches. (I've rebuilt probably 12 motors and never seen journals this clean) anyway, I digress ...
The heads have been redone at some time in the past - had a Fel-Pro blue head gasket, and new valve seals. When I pulled the rocker-shaft off I noticed that the valve springs were different heights.
Took the heads off and flipped them over - and the intake valves looked good, but the exhaust valves were sunk as much as 1/8" into the head ... thought to myself that the seats and valves were eaten up, but pulled them out and found out that they were fairly new valves and that the seats had been machined to accept the new valves, but they had to eat away a lot of material to get some to seat right.
All of that to get to the question - It would seem to me that this is a "bad thing". Am I right?
Even though the valves sit nicely in the seats, wouldn't the higher spring height cause the valves to always be partially open when the lifters pumped up?
Also, wouldn't this cause problems in getting the exhaust out of the cylinder? .125" out of the +-.420" cam "lift" would be below the head suface.
I didn't see any burning on the valves like exhaust was being squeezed in getting out, so my theory is that I was basically getting no compression as the valves never closed.
I'm scheduled to get new seats put in - but wanted to make sure that my logic was sound in doing this and that I'm not wasting the money.
Thanks,
Ken C.
'64 W200
'69 Road Runner
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