Beefy valves...
I'm wondering who makes upgraded valves for the M20. So far, I know of Schrick (at $55-75 each!!), and I've seen some from VAC (enormously overpriced), and some from IE (reasonable). The usual places I go to for valves have nothing for BMWs: Manley, Ferrea, etc... I'm having issues with exhaust valves getting too hot (not enough seat time with the big cam...), and also the stem ends getting trashed. The IE valves look OK, but do any engine builders in here have any experience with them or know where they're from? I'm not looking to increase valve size, just upgrade strength and heat tolerance.
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Mike
'91 325i track car. Mostly... -
Are you sure that the engine isn't running lean (from dyno pull data)? While a big cam does increase the valve open time, that time is still a small fraction of the closed time. If the engine is running stoch I'd think there would still be plenty of cooling time. But if it is running lean the excessive head temps could burn the valves.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL -
With everything torn apart, I can see that it is running a touch lean, but not enough to burn valves. Probably a combination of the two. The beat up stems is a head-scratcher, though. I really doubt selective valve float-only half the exhaust valves display this.sigpic
Mike
'91 325i track car. Mostly...Comment
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