Hardened Valve Seats
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Junior User
Joined: Feb 2001
Posts: 94
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Hardened Valve Seats
Recently I helped a friend of mine put a rebuilt 302 in his 87 F150 EFI. We finally got it going to realize the head gaskets were blown, so we sent the heads of to a machine shop and they checked out good except they didnt have hardened seats. My question is how long do you think the soft seats will last without running leaded gas? I know you can be lead additives but they wont work with the EFI will they? My friend is a college student so he dont have the $400 to put the harden seats in?
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Joined: Jan 2001
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From: Virginia
Hardened Valve Seats
If you use the truck for normal driving with ocasional hauling, the heads will last a long time. If the truck is worked hard with lots of heavy hauling, it will aggravate the seat problem. What will happen over time, is the valve will slowly pound itself up into the seat, till the lifter is not able to adjust itself any more, then the lifter will start not letting the valve close all the way. Eventually it will burn the valve and cause a miss in the engine. But the time limit is how hard you run the engine. These must be an old set of heads somebody put on to raise the compression ratio of the engine.
