reebadoo Posted September 19, 2017 Share Posted September 19, 2017 i have a ford 400 engine and the heads have been done once before with sealed power valves. the valves are v-2075 and v2075 and i was wondering if the sealed power valves hold up well or if there are any other similar options for valves. and if you are cleaning up the valves and two of the eight are bad would you replace all eight? one out of each head was bad. any advice would be of great assistance! Link to comment Share on other sites More sharing options...
PetesPonies Posted September 19, 2017 Share Posted September 19, 2017 OEM quality valves are fine for a street driven vehicle. If the valves have already been replaced, what makes two of them bad now? Some pitting, especially on the exhaust valve, is typical and what is removed when a valve job is done. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 20, 2017 Share Posted September 20, 2017 How many miles since the last valve job was done? What kind of use does this truck see? Define "bad". Are they worn out? Bent? Burnt? How do the seats and guides look? What springs are you using? Link to comment Share on other sites More sharing options...
reebadoo Posted September 20, 2017 Author Share Posted September 20, 2017 How many miles since the last valve job was done? What kind of use does this truck see? Define "bad". Are they worn out? Bent? Burnt? How do the seats and guides look? What springs are you using? two of the valves are cracked. i will put up a few pictures once i get a chance. but one valve is cracked from the edge in about 1/8th of an inch and the other is maybe 1/16th cracked through from the top to the bottom. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 20, 2017 Share Posted September 20, 2017 two of the valves are cracked. i will put up a few pictures once i get a chance. but one valve is cracked from the edge in about 1/8th of an inch and the other is maybe 1/16th cracked through from the top to the bottom. Exhaust valve? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 20, 2017 Share Posted September 20, 2017 two of the valves are cracked. i will put up a few pictures once i get a chance. but one valve is cracked from the edge in about 1/8th of an inch and the other is maybe 1/16th cracked through from the top to the bottom. Only time I've ever seen a cracked exhaust valve was from running the engine without any exhaust. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 21, 2017 Share Posted September 21, 2017 Only time I've ever seen a cracked exhaust valve was from running the engine without any exhaust. Burned valves are a common problem. It most always happens to the exhaust valve as it only has hot air passing by it for the nano second it is lifted off the seat. It works much harder and hotter, than the intake valve. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 21, 2017 Share Posted September 21, 2017 Only time I've ever seen a cracked exhaust valve was from running the engine without any exhaust. I've never seen a cracked valve. Burned ones, frequently. But not cracked. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 21, 2017 Share Posted September 21, 2017 I've never seen a cracked valve. Burned ones, frequently. But not cracked. A "burned valve" is a generic term to mean many things. Typically, its when a piece is missing. That piece that is missing starts as stress cracks. I'm assuming this is what the poster saw, the beginning of a burned valve. The craziest thing I have even come across was a "tulipped" valve. The valve had deformed such that it no longer sealed against the seat. Imagine the shape of a tulip :) Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 21, 2017 Share Posted September 21, 2017 A "burned valve" is a generic term to mean many things. Typically, its when a piece is missing. That piece that is missing starts as stress cracks. I'm assuming this is what the poster saw, the beginning of a burned valve. The craziest thing I have even come across was a "tulipped" valve. The valve had deformed such that it no longer sealed against the seat. Imagine the shape of a tulip :) Imagine smashing *your* head against the seat 30-40 times a second. Once a guide starts to get sloppy and the valve does not land concentric they will deform and also get too hot because of the lack of heat sink. Link to comment Share on other sites More sharing options...
Recommended Posts