lead substitute??

[z2o_what]

im running d0oe 351 heads on my current engine. i reseated the valves (valve gring and drill) myself. the heads do not have hardened seats, and i have been using a lead additive. so far i have over 200 miles on engine with no problems.

so... should it be safe using just the additive or am i going to run into valve seat problems down the road (so to speak)?

 

[z2o_what]

ttt

 

[samickguy15]

.

From what I understand, if you are going to beat on the motor pretty hard you should get hardened seats. If you are using it as a street car with an occassional race, you should be fine. If I were you, and had the money, I would get hardened seats put in.

 

[montegoman351]

I read on Lucas oil's website that the fuel additive they make can double as a lead substitute. I ran it for a long time, before I rebuilt the engine, and the insides of the engine were pretty clean.
But this was on a 135,000 mile cleveland, so the valves were starting to recess anyway, since I only only drove the car for 30,000 miles before the cam bearing babbit snuck past the oil pump screen, and needless to say, I totally redid the engine.

 

[montegoman351]

whoops, i pushed the button twice

 

[65ShelbyClone]

A stock cam and heads with soft seats and unleaded gas will last around 60,000-80,000mi before the sealing goes away. With a lumpy cam, expect the valves to pound out and sink much faster. I had some 289 heads sink a few valves in about 12,000 miles with a mild(~.475) hydraulic flat cam. They were replaced with E7s and no more problems.

My point is that it will be more economical in the long run to get hard seats.