The Stovebolt Site Forums The Shop Area Engine Shop need advice: should my exhaust valve be updated

Having my 235 rebuilt. It is at the machine shop as I write. I've been reading about the rebuild prosess and there is mention about upgrading the exhaust valve seats or exhaust valves to cope with todays unleaded fuels. Typically my truck only gets out on weekends with around 50 to 100 miles put on it in a weekend if that much.
With this type of driving, do I need to upgrade the valves or seats?
Thanks
Rick.........

No. Too much has been put into that. With the mileage most old cars and trucks see, and with most not really being pushed hard, there's really no need to upgrade if the valves are still servicable. Just have them properly reground and you'll be fine.
Now, for a counterpoint of sorts, if you have a valve that's not able to be refurbished, say bent, burnt, or worn out, I would suggest to go ahead and upgrade since it is being replaced anyway, Not much difference in cost. I had mine done,as my engine had several bad valves (including a severly burnt #5 exhaust) for $12 a valve, installed.

I have hard seats installed if the seats are bad. If they will grind, I leave them. I grind them myself, so I make the decision. Be sure you check the valve guides. Most of them are worn. I buy NOS valves on eBay whenever I can. I trust a 50 year old aftermarket valve more than a new off shore one. I run lead substitute in all my old jalopies. I probably don't need it, but I saw a lot of old engines that were still being worked in the 70's and 80's suck the valves in with unleaded.

If you're replacing valves, and stainless steel exhaust valves are available, it's a good idea to go with the newer alloy. Unless you need to replace the valve seats anyway, it's not really necessary to go to the stellite seats. Stellite is really nothing new for valve seats- - - -Propane-fuel engines have needed them for decades. The idea that leaded fuel somehow lubricated valve seats has sort of been debunked, but I have seen examples of engines that were switched from leaded to unleaded gas that had problems with exhaust valves receeding into the head. I think it was more of a situation of abuse and/or heavy loading, than actual fuel-related problems.
Jerry

I have many many miles on original engines in old cars and trucks. What i have found is they are fine until the valve seats are ground, which removes any residual hardening or lesd. Next the fresh valve job does not last long because the valves sink into the soft cast iron of the head. Having been through this several times, and having to pull the head/heads for a re-do, I have become a believer in hardened seats. Original valves themselves can usually be reground as long as they are straight. I can't imagine doing this without doing a complete job while I'm there. Valve guides are knurled, springs replaced, and I like to have PC seals installed. I've had much better success with them than the old umbrella style seals.

Devin