Working_Class_S

Regions will specify different maintenance intervals and sometimes different oils. I believe it wa American Honda than began to specify 5w20 when 30w was specified in Japan on the same cars. This was to meet CAFE regulations. Japan still eats whales and has current emissions standards similar to what we had in the late 80s. When the S2K came out, manufacturers were pushing for longer tuneup intervals because they became an indicator of quality for the consumer. If valve adjustments were to be required every 15 like they should be, the tuneup interval would be similar to that of an exotic.

crthomas1952

I hear you, Bill. I called the dealer to inquire about a valve adjust. They said $240; I have seen posters ask this but no answer. So, I asked them how often it needs to be done, and they said there is no scheduled interval. So, I did some more track weekends and then got around to doing the valve adjust yesterday. Intakes were close, mostly in spec, but on exhaust side had a couple in spec, couple a bit tight and 4 nearly closed. So, now my compression is 195, 220, 185, 255. Gonna need a valve job I guess.

windhund116

Those look pretty toasty. What kinda compression you getting?

IMHO, it's not the absolute amount that the valves are too tight --- but the change in duration of contact of the valve face with the head. So, kinda depends on how hot your cam setup is and how fast (RPM's) the engine is turning. Duration of contact is how valves transfer heat to the head. Too little transfer time = burnt valves.

Slowcrash_101

That's some abnormally high compression in cylinder 4.