Is this valve toast?

[JNM240]

Ok, so ive pulled all of my valves out of my cylinder head, took them to work and polished them on our wire wheel buffer. They all came out great, but this one is suspect. Is it burnt? Should i replace it? The rest look excellant, i just dont want this motors weakness to be something stupid like a valve i shouldve replaced.



If it does need to be replaced, anybody got one sitting around and willing to be donated to me? Its the #4 on the intake side, btw.

Jason

[capowered240]

I would just replace it if I was you. Better safe than sorry.

[AWDB12wagon]

That thing looks like someone dropped bb's down inside it. I would take the whole head to a machine shop and have a 3-angle valve job done on it...replace the valve stem seals too. May also want to have the guides checked and the head surface for warpage.

[JNM240]

Did everything else myself, even had the master tech at work look at the head and valves. He's the one who told me that it was burnt. Ive replaced the valve stem seals and am in the process of polishing the valves into the seats and reinstalling them.

Speaking of reinstalling the valves, MAN THESE THINGS ARE HARD TO INSTALL! The came out like cake, but getting the valve spring retainer keepers into place is only about 2 steps short of impossible! And yes, i have the correct type of valve spring compressor. I spent nearly the whole day just getting half of the valves back in, and thats after prepping them!!

Thanks for the replies, im gonna have my local Nissan dealership order me a new valve. Hopefully there wont be any surprises, unlike trying to order the main crank bolts last month.

Jason

[AWDB12wagon]

Yeh, they're a pain in the arse to get the keepers back in. My trick that I'll share with you is a mini screw driver with a dab of grease on it, place the keeper on the grease, set it where you want it and either push it off with anouther screw driver or manuver it off.

[progman]

the engine started to erode a soft spot. soon enough that valve will be bad. Was there any wear on the valve stem or valve guide? if those are worn it will make the valve head wobble a little and not seat all the way that it needs to transfer the heat into the head.

[JNM240]

Nope, everything else looked awesome. Ive ordered a new valve from Nissan (i know the chick at the parts desk, i got it at cost!). Ive been installing the valves as time and patience permits, including polishing up the valve seats. Every valve seat looks perfect. It was probably like you said, a soft spot in the metal eroding. Will be fixed soon enough. I cant wait to mount the cylinder head onto the block (with my ARP head studs), then it will look soooo much more like a real motor!!!