PetesPonies Posted September 21, 2017 Share Posted September 21, 2017 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. 30-40 times a second is slow :) When I was teaching Auto, I used to use an Indy engine as an example. 15000 RPMs and explain to the students how fast things were moving at that speed. It's scary fast. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 21, 2017 Share Posted September 21, 2017 30-40 times a second is slow :) When I was teaching Auto, I used to use an Indy engine as an example. 15000 RPMs and explain to the students how fast things were moving at that speed. It's scary fast. Yeabutt it's a truck engine..... I've seen plenty of seat recession where the valve pulled right up into the head. No one needs really fancy valves in this application. I'm looking to redo a set of heads for my truck asap. Light porting and a compression cut once I get the short block worked out. Link to comment Share on other sites More sharing options...
reebadoo Posted September 21, 2017 Author Share Posted September 21, 2017 Yeabutt it's a truck engine..... I've seen plenty of seat recession where the valve pulled right up into the head. No one needs really fancy valves in this application. I'm looking to redo a set of heads for my truck asap. Light porting and a compression cut once I get the short block worked out. im not sure how many miles have been put on the engine sense the heads were done. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 21, 2017 Share Posted September 21, 2017 Yeabutt it's a truck engine..... I've seen plenty of seat recession where the valve pulled right up into the head. No one needs really fancy valves in this application. I'm looking to redo a set of heads for my truck asap. Light porting and a compression cut once I get the short block worked out. I don't think anyone suggested fancy valves. I wanted to know if they were the exhaust, as i suspect. I would replace all 8 exhaust and leave the intakes after a cut. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 21, 2017 Share Posted September 21, 2017 im not sure how many miles have been put on the engine sense the heads were done. THat is exactly how a burned valve starts. Typical. What causes it? Well if your seats and valve faces were not matched, there is less contact area at the seat. The small the contact the less time to transfer heat back to the head. The result is what you are showing. Replace all the exhaust, get a valve job done, checking guides, grinding the seats, etc. Link to comment Share on other sites More sharing options...
reebadoo Posted September 21, 2017 Author Share Posted September 21, 2017 THat is exactly how a burned valve starts. Typical. What causes it? Well if your seats and valve faces were not matched, there is less contact area at the seat. The small the contact the less time to transfer heat back to the head. The result is what you are showing. Replace all the exhaust, get a valve job done, checking guides, grinding the seats, etc. i ground down all the other valves to make a nice face. the intake match up really well so i just need to do the valve seats on the exhaust and the intake all seat really nicely. so im just trying to figure out what to do with the exhaust valves. and exhaust valve seats. and the valve guides are aout .002 over spec so i think i will need inserts to make sure that the valves dont go sideways. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 21, 2017 Share Posted September 21, 2017 I don't think anyone suggested fancy valves. I wanted to know if they were the exhaust, as i suspect. I would replace all 8 exhaust and leave the intakes after a cut. Look at the first post. I got the impression that he felt maybe 'better' valves would not fail like these did. Re: seat width... For a given cam, time on the seat is what ever it is. But *area* for heat transfer, over time on seat goes up dramatically. As you said it's pretty amazing that ice's hold together as well as they do. I don't teach but I DO learn. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 21, 2017 Share Posted September 21, 2017 Look at the first post. I got the impression that he felt maybe 'better' valves would not fail like these did. Re: seat width... For a given cam, time on the seat is what ever it is. But *area* for heat transfer, over time on seat goes up dramatically. As you said it's pretty amazing that ice's hold together as well as they do. I don't teach but I DO learn. So OP, you have a valve grinding setup? Link to comment Share on other sites More sharing options...
reebadoo Posted September 21, 2017 Author Share Posted September 21, 2017 So OP, you have a valve grinding setup? i am going to school for diesel technology. and they have everything to do heads in the building and the block will be machined either at the school in the high performance engine shop or at an engine shop in town. im not sure which yet. unfortunately i dont have much money so im trying to do it right but do it on a budget because i am a student in school haha. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 21, 2017 Share Posted September 21, 2017 i am going to school for diesel technology. and they have everything to do heads in the building and the block will be machined either at the school in the high performance engine shop or at an engine shop in town. im not sure which yet. unfortunately i dont have much money so im trying to do it right but do it on a budget because i am a student in school haha. You originally asked about Sealed Power valves. In my limited experience of buying valves those are fine. And those two need to be replaced. Link to comment Share on other sites More sharing options...
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