Rebuilding a 251 Spitfire; Looking For Advice on Valves

[ConMan50]

I've completely torn down the engine on my 1950 Chrysler Windsor Sedan, as the engine was seized when I bought it. I have yet to collect any precision measurements (I don't own any machinist's tools), but I did notice a few things as I disassembled the engine, and I'd like to know if any of you have any advice. Primarily concerning me right now is the valve train. While some of the valves slid right out of their guides after I had removed their springs and retainers, there were a few that were so stubborn, they required vice grips, penetrating oil, and nearly an hour of twisting and tugging to remove. What's odd, is that aside from the damage inflicted by my vice grips, I couldn't find any apparent deformities on the stubborn valves. I'm wondering at this point if there's any good way to determine if the problem was my valves, valve guides, or both. 

 

Additionally, after finding what's available on Vintage Power Wagons, I've been considering the possibility of installing modern valve seats and valves to allow for the use of unleaded fuel. I hope to one day drive this car daily, and don't want to deal with tracking down and adding a lead substitute at every fill-up. Does anyone here have experience in running these fatheads on unleaded? Do the original valves ruin themselves if you do?

 

This is my first engine rebuild, and any advice on the subject is greatly appreciated.

[Niel Hoback]

Mopar engines already have hardened valve seats. Since 1933, I think.

[dpollo]

 Your engine already has hardened exhaust seats as mentioned above.  I have had engines running over 80 000 miles

on unleaded gas with no problems.

 

 If you clean the guides there will not be any problems like those you encountered on disassembly

it was just an accumulation of rust and carbon .  There is a good chance you may have bent the stubborn valves but this will

be evident when you have them refaced. Maybe it would be better to replace those valves.

[Andydodge]

Don Coatney who regularly posts on this forum installed a 25" Chrylser/Desoto 6 in his 48 Plymouth and used sheverolay(as he calls them) valves in rebuilding his engine, primarily as I remember him saying they were cheaper/easier and better profiled..........but he will give you the info if you contact him direct..........andyd

[Don Coatney]

Two suggestions. If you don't have a engine manual for your engine get one before you go any further. Also go to the resources tab at the top of this page and read everything there.