Quote:
Originally Posted by NoHaveMSG
I lost both intakes on #2. As far as I can tell I don't think oil pressure is the culprit. Our valve specs are a bit looser then I expected so the oil pressure against the lifter and pivot may have a small effect, but we are talking .005in lash it may be taking up out of the total static lash. I think it is a geometry issue as Subaru's fix for it was to lengthen the valve stem and deepen the pocket of the rocker. The updated engines do have issues still periodically with kicking out the rockers.
|
Element Tuning did my original build. I would have sent the engine back to them but they moved from Maryland to Florida and I wanted someone more local. I've been in touch with Phil concerning my problem and in our last communication the oil pressure vs lash question came up and he said: "If the lifter wasn't hydraulic the rockers would eject very quickly as there's nothing holding them in place securely. The oil pressure takes up the lash. That's why i made the comment about how he said the rockers are loose, as they are, but by how many thousandths. They pivots are in the oil pressure galley, then push up, exposing a relief port, and then there is also an oil port into the roller socket. The roller socket has barely a relief for oil to escape. On the cam's base circle you can wiggle the crap out of the rocker with only 5-8 thousandths (intake/exhaust) clearance but that's not loose, that's correctly lashed. I'm not saying you can't go tighter but you better have a good idea what your new valve seating recession will be after run it, what service interval you are trying to achieve, and what overall temperature you are lashing for as higher temps require looser clearances to deal with expansion." Seems logical.