SR20DET EXHAUST VALVE FAILURE

[manka4343]

Has anyone run across this before? Both #4 exhaust valves broke about 1/2" from the top (below the keeper groove) and then very bad things happened to the rest of the valve when it fell down and met the piston.. Is this a common problem with this engine? Any idea of the root cause and how to fix it?

[Slipstream]

Are you sure the piston didn't slam into the valve first causing it to break. Possible bind or float?

[manka4343]

thought about that, but why would the stem break at the top? I've seen valves tagged by pistons before, and they usually bend the head over or break it off.. Both of the #4 exhaust valves had the stem broken at the top, and when I pulled the head, the rest of the valve was jammed up into the guide with the heads bent over, but still attached.

[Hijacker]

First time I've heard of a failure like that on these motors. But there's a first for everything.

I'm tempted to say it was valve float that caused it since the breaks happened near the top. SRs are notorious for valve float when you try to get rev happy without the propper precautions (rocker arm stoppers, stronger valve springs, etc)

[manka4343]

that's probably what happened then.. well on to fixing it.. I ordered all new BC stuff today (stroker kit, cams, valves, springs, Ti retainers) and JWT valve guides and valve stem seals.. Does anyone make Ti keepers? Also, which rocker arm stoppers should be used?

[Hijacker]

I use greddy RASes, but you can't go wrong with any of the name brand guys.