Which valve stem seals leak
#162
Funny thing Adaindj, (and I am showing my age here); in the past engines have not always had much in the way of guide seals and they didn't smoke... well, much. Some of the mid 1950's-60's era V-8's used nothing more than an O-ring atop the guide to "deflect" excess oil. In going thru a 1960 recently Catalina I ran into a valvetrain design where Pontiac had actually drilled oil galleys to feed oil thru the guide, and they didn't smoke... much.
I can't believe that a well made stem seal of this modern generation could cause so much trouble. If your guides are somewhere in the .0015-.0018" range then I would think that the oil control issues (in the amount that you are describing) would be coming from another source. I believe that you are onto something when you talk about loose guides and wobbely valves.
btw: I did pick up that other car... now how long before I have Gabe turn up the boost? cj
I can't believe that a well made stem seal of this modern generation could cause so much trouble. If your guides are somewhere in the .0015-.0018" range then I would think that the oil control issues (in the amount that you are describing) would be coming from another source. I believe that you are onto something when you talk about loose guides and wobbely valves.
btw: I did pick up that other car... now how long before I have Gabe turn up the boost? cj
#163
Funny thing Adaindj, (and I am showing my age here); in the past engines have not always had much in the way of guide seals and they didn't smoke... well, much. Some of the mid 1950's-60's era V-8's used nothing more than an O-ring atop the guide to "deflect" excess oil. In going thru a 1960 recently Catalina I ran into a valvetrain design where Pontiac had actually drilled oil galleys to feed oil thru the guide, and they didn't smoke... much.
I can't believe that a well made stem seal of this modern generation could cause so much trouble. If your guides are somewhere in the .0015-.0018" range then I would think that the oil control issues (in the amount that you are describing) would be coming from another source. I believe that you are onto something when you talk about loose guides and wobbely valves.
btw: I did pick up that other car... now how long before I have Gabe turn up the boost? cj
I can't believe that a well made stem seal of this modern generation could cause so much trouble. If your guides are somewhere in the .0015-.0018" range then I would think that the oil control issues (in the amount that you are describing) would be coming from another source. I believe that you are onto something when you talk about loose guides and wobbely valves.
btw: I did pick up that other car... now how long before I have Gabe turn up the boost? cj
#166
Reposted from the other thread here:
Issues with Supertech Viton Seals
I'm reposting this in order to keep the info on the Sticky.
"OK! I've finished a fairly exhaustive test to evaluate these valve seals. Somehow I've ended up with 7 different seals to test.
I decided to make up some kind of test in order to evaluate actual performance. Measuring the various dimensions is all well and good. But due to the spring, material type and shape/form of the lip, I can't positively establish which is really any better/worse.
So I made up a way to mount each valve seal as mounted on a valve stem. Then I'd simply add weight until the grip on the stem is lost.
Now all of these basically have a 'slip point' at which they whip right out. So I tried to very carefully measure that point. Using engine oil for lube, I put these on and gave them a chance to fall (over and over) in order to establish a repeatable measurement. In most cases I tested 3-5 samples. Unfortunately, some of these only had one or two samples to test (US Seal EOK, Felpro)
The results make perfect sense. Something we already know: DON'T INSTALL SUPERTECH VALVE SEALS.
Overall winner? A seal that I don't even have a new one to test. OEM. I'm going to guess that the seals on this motor are fairly well used. But I have no idea.
The Supermiata are great. Really tight fit and strongest grip overall."
Issues with Supertech Viton Seals
I'm reposting this in order to keep the info on the Sticky.
"OK! I've finished a fairly exhaustive test to evaluate these valve seals. Somehow I've ended up with 7 different seals to test.
I decided to make up some kind of test in order to evaluate actual performance. Measuring the various dimensions is all well and good. But due to the spring, material type and shape/form of the lip, I can't positively establish which is really any better/worse.
So I made up a way to mount each valve seal as mounted on a valve stem. Then I'd simply add weight until the grip on the stem is lost.
Now all of these basically have a 'slip point' at which they whip right out. So I tried to very carefully measure that point. Using engine oil for lube, I put these on and gave them a chance to fall (over and over) in order to establish a repeatable measurement. In most cases I tested 3-5 samples. Unfortunately, some of these only had one or two samples to test (US Seal EOK, Felpro)
The results make perfect sense. Something we already know: DON'T INSTALL SUPERTECH VALVE SEALS.
Overall winner? A seal that I don't even have a new one to test. OEM. I'm going to guess that the seals on this motor are fairly well used. But I have no idea.
The Supermiata are great. Really tight fit and strongest grip overall."
#167
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Location: Taos, New mexico
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I have a fresh rebuilt motor and I'm 90% sure my seals are leaking. I went with the supermiata ones after reading this thread. The engine builder checked the guides and said they were in spec, so didn't replace any of them. They also installed the seals, did a valve job, and built my bottom end. I have ~800 miles on the motor and have noticed that it very slightly smokes, but only after idling for 10+ minutes and then i rev the motor, or engine braking down long (1+ mile) downhills.
Otherwise under WOT, or even normal driving conditions around town it does not smoke at all.
I plan on proving this theory by pulling the intake and/or exhaust manifold to check for leakage, though the smoking is so minor I probably won't bother until the dead of winter. I'll update this thread at that time.
As a data point when I pulled the head for the rebuild, the old valve stem seals were clearly leaking, a lot. I'm now wondering if those should have been replaced as well.
The builder of my engine and head were well known shop that works with spec miatas, so I trust they did things correctly.
Otherwise under WOT, or even normal driving conditions around town it does not smoke at all.
I plan on proving this theory by pulling the intake and/or exhaust manifold to check for leakage, though the smoking is so minor I probably won't bother until the dead of winter. I'll update this thread at that time.
As a data point when I pulled the head for the rebuild, the old valve stem seals were clearly leaking, a lot. I'm now wondering if those should have been replaced as well.
The builder of my engine and head were well known shop that works with spec miatas, so I trust they did things correctly.
#170
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Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Going to drop off my head to the machine shop this week and just wanted to confirm that the super miata VSS are the way to go right?
I used felpro when i changed them out and didn't notice any ill effects, but I have leaky valves and wanted to have the head refreshed and was hoping to go with the least leaky option which sounds like super miata at this time, yes?
I used felpro when i changed them out and didn't notice any ill effects, but I have leaky valves and wanted to have the head refreshed and was hoping to go with the least leaky option which sounds like super miata at this time, yes?
#175
Anyone use these Miataroadster Viton valve seals?
https://miataroadster.com/miataroads.../i-411995.aspx
I have a set of Mazda valve seals that came with the Mazda rebuild kit, but was wondering if these Miataroadster Viton seals are worth. After reading through this thread again, I am pretty sure I will just use the Mazda seals since I have them.
https://miataroadster.com/miataroads.../i-411995.aspx
I have a set of Mazda valve seals that came with the Mazda rebuild kit, but was wondering if these Miataroadster Viton seals are worth. After reading through this thread again, I am pretty sure I will just use the Mazda seals since I have them.
#178
I'm looking to replace the valve steam seals in my 2000 after noticing that it burns a bit of oil when revving it out, and I'm going turbo.
I looked on eBay, and found some Supertech valve stem seals (Supertech Viton Valve Stem Seals 1.6L 1.8L Mazda Miata / Ford Escort BP B6D MX5 | eBay), and considering the name, and the price I jumped right on them.
I was watching a video on youtube (https://www.youtube.com/watch?v=7qyuGLzRLyM), and he mentioned ebay supertech valve steam seals. He says that his car burned a lot of oil after installing them, but it could be a lot of other things as well.
This has me concerned that I just dropped money on some junk.
Has anyone heard anything about these seals and whether or not they're any good?
I looked on eBay, and found some Supertech valve stem seals (Supertech Viton Valve Stem Seals 1.6L 1.8L Mazda Miata / Ford Escort BP B6D MX5 | eBay), and considering the name, and the price I jumped right on them.
I was watching a video on youtube (https://www.youtube.com/watch?v=7qyuGLzRLyM), and he mentioned ebay supertech valve steam seals. He says that his car burned a lot of oil after installing them, but it could be a lot of other things as well.
This has me concerned that I just dropped money on some junk.
Has anyone heard anything about these seals and whether or not they're any good?
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