Quote:
Originally Posted by 67htc
From what understand, if you don't put your engine under a lot of heavy load, like pulling long grades with your foot in it, you can get away without the hardened seats for some time.
Tetraethyl lead was used as an anti-knock additive, but also served the purpose of acting as a cushioning agent on the valves / seats.
If you run gonads-to-the-wall without leaded gas and hardened seats, you will erode the valve heads and eventually "suck" a valve (or two).....  |
Well, first, I don't understand why heavy loads have any impact (pun not intended) on valve heads hitting the seats. The impact force is solely a function of the valve springs, and that force will be the same at a given RPM whether the engine is being lugged going up a hill or being revved in neutral.
As for the lead cushioning effect, that's true, but I can provide anecdotal information in the form of the 66 400 motor with stock B heads and plain seats. I am not an easy driver and let's just say that this particular engine had a hard life for many years under my right foot as a daily driver. On a steady diet of unleaded premium there was no degradation and no valve "sucking". Was there an existing cushion of lead already there? Possibly, but that would have been a long time ago.
For a car that's not a daily driver, I doubt you'll see the difference in many years of weekend driving.