Valve seat materials
10-21-2016, 07:18 PM
#1
Valve seat materials
Seems like a topic that never gets brought up. I see everyone always saying how "inconel" valves must be used for Marine. But what about the seats?
Full Force Tim, and a few others, have had issues with excessive exhaust valve seat wear on the AFR heads, after a relatively short time. I noticed Dart is using "powder metal" seats, as does Engine Quest, while AFR uses a standard ductile iron. I think I remember reading somewhere, that Teague marine installs "Tucker" valve seats in their heads , which are a really high quality seat.
From some of the articles I've read on the topic, seems most of the OEMS have gone to powder metal seats, as they last a very long time.
Full Force Tim, and a few others, have had issues with excessive exhaust valve seat wear on the AFR heads, after a relatively short time. I noticed Dart is using "powder metal" seats, as does Engine Quest, while AFR uses a standard ductile iron. I think I remember reading somewhere, that Teague marine installs "Tucker" valve seats in their heads , which are a really high quality seat.
From some of the articles I've read on the topic, seems most of the OEMS have gone to powder metal seats, as they last a very long time.
10-21-2016, 07:33 PM
#2
Registered
iTrader: (2)
The powder metal seats are a "cold casted" seat. With the cold casting there is much more control over the grain structure. From my own experiences Tucker seats are the best. Even in turbo car motors they hold up the best. Sterling uses Copper Berilium seats in all his motors along with Inconel exhaust and intake. This is a big no no in the marine world. His motors have a mandatory yearly tear down and valve job at a minimum if you are luckily and a lot of times valve seats are beat so bad they need replaced. Throw in a Tucker seat and all your issues go away. I'd really like to get some input on the Durabond seats before I continue with my winter project. Great topic for discussion.
10-22-2016, 09:53 AM
#4
I've spent the morning reading a paper from a study the EPA, and department of agriculture wrote on the effects of valve seat recession, and unleaded fuels. Paper was written 30 years ago. They did several farm engines, but they also did a 454 Chevy engine. They ran it on strictly unleaded with cast iron valve seats, then steel valve seats, cast iron with lead additives of various concentrations, for 200 hour tests in each scenerio.
The worst setup, that suffered the most exhaust valve seat recession, was the straight unleaded, cast iron valve seat. By 60 hours, the valve seats were already showing .015 of valve seat recession. By 140 hours, the seat recession on some cylinders was up to .030.
The next worst, was the steel valve seat, straight unleaded. Valve seat recession by 60 hours, was in the .010 range, and by 140 hours, was up to .020. Better, but still not great.
Using a lead /lubricant in the fuel, at a mixture of 250lbs per 1000 barrels of gasoline, the cast iron valve seat recession, stayed under .005 for 140 hours.
Using a mixture of .1 gram per liter of lubricant in the fuel, by 140 hours, the cast iron valve seat recession was basically not an issue at all.
In the valve seat world, engines running a dry fuel, like Propane, Natural gas, must have special valve seats. Reading that article , almost makes me want to consider running a lead substitute like this in my fuel https://www.redlineoil.com/content/f...ech%20Info.pdf
The worst setup, that suffered the most exhaust valve seat recession, was the straight unleaded, cast iron valve seat. By 60 hours, the valve seats were already showing .015 of valve seat recession. By 140 hours, the seat recession on some cylinders was up to .030.
The next worst, was the steel valve seat, straight unleaded. Valve seat recession by 60 hours, was in the .010 range, and by 140 hours, was up to .020. Better, but still not great.
Using a lead /lubricant in the fuel, at a mixture of 250lbs per 1000 barrels of gasoline, the cast iron valve seat recession, stayed under .005 for 140 hours.
Using a mixture of .1 gram per liter of lubricant in the fuel, by 140 hours, the cast iron valve seat recession was basically not an issue at all.
In the valve seat world, engines running a dry fuel, like Propane, Natural gas, must have special valve seats. Reading that article , almost makes me want to consider running a lead substitute like this in my fuel https://www.redlineoil.com/content/f...ech%20Info.pdf
10-22-2016, 10:07 AM
#5
Im sure most know this already, but for the younger guys who may not.....back before the days of "unleaded" gas, we had leaded fuel. There was a transition period, where both fuels were available at the pump. The epa pretty much got rid of leaded fuels, in the days of the catalytic converter introduction. Back then, if you had a car that required leaded fuel , and did not have the hardened valve seats for unleaded fuel, and you ran unleaded fuel, the valve seats didnt last long.
Today, all engines must run on unleaded obviously. For oem engines to last the 150k mile emission standards, a quality valve seat must be used that can go the distance. Must be why they have now gone to sintered powder metal exhaust seats.
As we know, the marine engines run very hot exhaust temps. A quality seat material must be used if you want to get life out of the valve seats. Our camshafts, springs, hp levels, are getting more extreme every day. The valve seats must not only seal the valve, but also have to transfer that extreme heat to the cooling system. Take an extremely hot valve and seat and slam them together with aggressive cam profiles, unleaded fuels, lean air fuel ratios, and then a basic ductile iron seat, its not surprising some guys are seeing this early valve seat recession on the exhaust valves.
Today, all engines must run on unleaded obviously. For oem engines to last the 150k mile emission standards, a quality valve seat must be used that can go the distance. Must be why they have now gone to sintered powder metal exhaust seats.
As we know, the marine engines run very hot exhaust temps. A quality seat material must be used if you want to get life out of the valve seats. Our camshafts, springs, hp levels, are getting more extreme every day. The valve seats must not only seal the valve, but also have to transfer that extreme heat to the cooling system. Take an extremely hot valve and seat and slam them together with aggressive cam profiles, unleaded fuels, lean air fuel ratios, and then a basic ductile iron seat, its not surprising some guys are seeing this early valve seat recession on the exhaust valves.
10-22-2016, 10:24 AM
#6
Registered
iTrader: (2)
Im sure most know this already, but for the younger guys who may not.....back before the days of "unleaded" gas, we had leaded fuel. There was a transition period, where both fuels were available at the pump. The epa pretty much got rid of leaded fuels, in the days of the catalytic converter introduction. Back then, if you had a car that required leaded fuel , and did not have the hardened valve seats for unleaded fuel, and you ran unleaded fuel, the valve seats didnt last long.
Today, all engines must run on unleaded obviously. For oem engines to last the 150k mile emission standards, a quality valve seat must be used that can go the distance. Must be why they have now gone to sintered powder metal exhaust seats.
As we know, the marine engines run very hot exhaust temps. A quality seat material must be used if you want to get life out of the valve seats. Our camshafts, springs, hp levels, are getting more extreme every day. The valve seats must not only seal the valve, but also have to transfer that extreme heat to the cooling system. Take an extremely hot valve and seat and slam them together with aggressive cam profiles, unleaded fuels, lean air fuel ratios, and then a basic ductile iron seat, its not surprising some guys are seeing this early valve seat recession on the exhaust valves.
Today, all engines must run on unleaded obviously. For oem engines to last the 150k mile emission standards, a quality valve seat must be used that can go the distance. Must be why they have now gone to sintered powder metal exhaust seats.
As we know, the marine engines run very hot exhaust temps. A quality seat material must be used if you want to get life out of the valve seats. Our camshafts, springs, hp levels, are getting more extreme every day. The valve seats must not only seal the valve, but also have to transfer that extreme heat to the cooling system. Take an extremely hot valve and seat and slam them together with aggressive cam profiles, unleaded fuels, lean air fuel ratios, and then a basic ductile iron seat, its not surprising some guys are seeing this early valve seat recession on the exhaust valves.
Platinum Member
10-22-2016, 03:55 PM
#8
Registered
I wondered about adding two stroke oil into gas. Have a good buddy who used to be a serious motocross racer. Ran 100:1 in his 4 stroke bikes when they came out, gave him a big advantage over others actually. Made more HP, everyone thought he was nuts and were baffled when they ordered tear-down inspections of his bikes only to find that they were bone stock. People accused them of running cheater overbore kits and were surprised when the overbore pistons they happened to have wouldn't fit down the jugs. They also use to run their two stroke bikes at closer to 20:1 and made more hp as well.
The biggest thing with the EPA meddling in our fuels seems to be what they are removing, usually has some lubricating property. Lead out of gasoline which was a great lubricant. Now they have pulled sulfur from diesel which is also a great lubricant. Notice how your older diesel engine lost MPG after the EPA low sulfur mandate took effect. A little two stroke oil also assists with cylinder ring sealing. That makes more HP. Also reduces upper cylinder friction. That frees up more HP. I don't see too many disadvantages to it. Throw some Klotz in your tank....smells great too!
So, does this mean that most valve seat related issues are due to improper lubrication rather than force of valve impact/bouncing/cam profile? Does the lubrication provide a film cushion on the seat preventing the propagation of the impact forces to the head material is the reason behind this?
The biggest thing with the EPA meddling in our fuels seems to be what they are removing, usually has some lubricating property. Lead out of gasoline which was a great lubricant. Now they have pulled sulfur from diesel which is also a great lubricant. Notice how your older diesel engine lost MPG after the EPA low sulfur mandate took effect. A little two stroke oil also assists with cylinder ring sealing. That makes more HP. Also reduces upper cylinder friction. That frees up more HP. I don't see too many disadvantages to it. Throw some Klotz in your tank....smells great too!
So, does this mean that most valve seat related issues are due to improper lubrication rather than force of valve impact/bouncing/cam profile? Does the lubrication provide a film cushion on the seat preventing the propagation of the impact forces to the head material is the reason behind this?
Last edited by Gimme Fuel; 10-22-2016 at 04:41 PM.
10-22-2016, 06:00 PM
#9
Registered
I've spent the morning reading a paper from a study the EPA, and department of agriculture wrote on the effects of valve seat recession, and unleaded fuels. Paper was written 30 years ago. They did several farm engines, but they also did a 454 Chevy engine. They ran it on strictly unleaded with cast iron valve seats, then steel valve seats, cast iron with lead additives of various concentrations, for 200 hour tests in each scenerio.
The worst setup, that suffered the most exhaust valve seat recession, was the straight unleaded, cast iron valve seat. By 60 hours, the valve seats were already showing .015 of valve seat recession. By 140 hours, the seat recession on some cylinders was up to .030.
The next worst, was the steel valve seat, straight unleaded. Valve seat recession by 60 hours, was in the .010 range, and by 140 hours, was up to .020. Better, but still not great.
Using a lead /lubricant in the fuel, at a mixture of 250lbs per 1000 barrels of gasoline, the cast iron valve seat recession, stayed under .005 for 140 hours.
Using a mixture of .1 gram per liter of lubricant in the fuel, by 140 hours, the cast iron valve seat recession was basically not an issue at all.
In the valve seat world, engines running a dry fuel, like Propane, Natural gas, must have special valve seats. Reading that article , almost makes me want to consider running a lead substitute like this in my fuel https://www.redlineoil.com/content/f...ech%20Info.pdf
The worst setup, that suffered the most exhaust valve seat recession, was the straight unleaded, cast iron valve seat. By 60 hours, the valve seats were already showing .015 of valve seat recession. By 140 hours, the seat recession on some cylinders was up to .030.
The next worst, was the steel valve seat, straight unleaded. Valve seat recession by 60 hours, was in the .010 range, and by 140 hours, was up to .020. Better, but still not great.
Using a lead /lubricant in the fuel, at a mixture of 250lbs per 1000 barrels of gasoline, the cast iron valve seat recession, stayed under .005 for 140 hours.
Using a mixture of .1 gram per liter of lubricant in the fuel, by 140 hours, the cast iron valve seat recession was basically not an issue at all.
In the valve seat world, engines running a dry fuel, like Propane, Natural gas, must have special valve seats. Reading that article , almost makes me want to consider running a lead substitute like this in my fuel https://www.redlineoil.com/content/f...ech%20Info.pdf
10-22-2016, 06:46 PM
#10
Registered
iTrader: (3)
Seems like a topic that never gets brought up. I see everyone always saying how "inconel" valves must be used for Marine. But what about the seats?
Full Force Tim, and a few others, have had issues with excessive exhaust valve seat wear on the AFR heads, after a relatively short time. I noticed Dart is using "powder metal" seats, as does Engine Quest, while AFR uses a standard ductile iron. I think I remember reading somewhere, that Teague marine installs "Tucker" valve seats in their heads , which are a really high quality seat.
From some of the articles I've read on the topic, seems most of the OEMS have gone to powder metal seats, as they last a very long time.
Full Force Tim, and a few others, have had issues with excessive exhaust valve seat wear on the AFR heads, after a relatively short time. I noticed Dart is using "powder metal" seats, as does Engine Quest, while AFR uses a standard ductile iron. I think I remember reading somewhere, that Teague marine installs "Tucker" valve seats in their heads , which are a really high quality seat.
From some of the articles I've read on the topic, seems most of the OEMS have gone to powder metal seats, as they last a very long time.
