For my Crosley engine rebuild unbeknown to me the valves I purchased are Stainless Steel both Int and Exh. I put in bronze guides from the same vendor. He gave me the guide clearance/seat specs. The Exh valve has a thicker margin than a stock valve while the Int margin is close to stock. Is the thicker Exh margin for heat, could it handle being thinner? How do SS valves wear with cast iron seats?
Yes the wider seat is for heat , if you mean seat , if you mean the thickness at the edge , the thickness is to allow for wear and reco. And probably to help stabilise in heat. if you don’t care for valve/seat life you could narrow the seat , but for why? Don’t think you’ll gain a heap of flow.
Here is a weird one for you. I rebuilt some 354 hemi truck heads with Hot Heads iron guides and stainless valves. Assembled the engine and was setting valves (adjustable push rods) and one valve was stuck. Took it apart and found this valve had several tiny beads 'welded' to its shaft. Stuck too tight to remove, ordered a new valve and put it back together. Engine runs fine. I never welded around the valve and never did anything electrical around the engine before this showed up.
I purchased stainless intake and exhaust valves to be installed in my Ford Y-block heads. I did a lot of research, read a lot of posts on a lot of forums and found that at least 90% of them called for the installation of either bronze guides or bronze liners. The machine shop gave me the choice of either bronze liners or guides. Although they were willing to install bronze guides (costs more), they recommended bronze liners, which they had used many, many times without a problem. I chose the liners. I've also read that Hardened exhaust-valve seats aren't necessary when using stainless valves; again, the suggestion went against the grain. I went ahead and had Hardened exhaust-valve seats installed.
I hate when stuff happens that you don't have a reason for. I know both Int and Exh valves are SS to 1/3 up the stem and then become steel, or high magnetic ss. I have a habit of polishing the stems lengthways with 400, sometimes it feels like the stem grind is rough, can't hurt.
I’d guess that’s material transfer, you can see where the material has been picked up from and then deposited.
Looks like a stem welded Eaton valve the missed a finishing operation. TRW valve had a hardened tip welded to the ste., with the stem and head forged from a single piece. Eaton valves were stem welded with the head and lower part of the stem a single piece and the rest of the stem friction welded to the lower part. They didn’t have the cap welded to the tip like TRR. Never could qualify Eaton valves in the days of high sulfur Diesel. The stems would corrode at the weld and the valve head would drop. Other manufacturers seemed to make Eaton valves, but the cost savings of going to Eaton wasn’t worth it. Perhaps other oems had the weld higher up on the stem, out of the combustion products. Sulfuric acid is formed with high sulfur (before ulsd) fuels.
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