Author Topic: Valve Stem seals  (Read 770 times)

colin evans

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Valve Stem seals
« on: May 31, 2024, 14:18:53 »
Hi All
Whilst the cylinder head is off I have taken the valves off to replace the stem seals, the valves and guides are good with hardly any movement. I have a few questions for the wiser ones about the seals please.

I have a mixture of the white plastic ones (inlet valves) and the black rubber ones (exhaust). Do I need to replace like for like, as the SL shop only offer a kit with 12 of the white plastic ones, not the exhaust type.

Also, they show an MB seal 1020530358 valve stem 9mm viton brown. I can't see this on my engine. I read on another forum that later 280SL's have grooved guides, I don't think mine has but to be honest it is quite hard to tell as there are wear marks. I have attached a pic of the outside, do either of these marks look like a seal groove? if so, where does it fit? This is the clearest pic I could get as the others are even less obvious.

Final question, how does the "lower seal" work? This is the part in the Haynes manual chapter 1 pic 32.2A. It looks like a sliding sealed 2 metal part that allows the spring to turn, but are there any serviceable parts? They are not listed in the SL shop parts store.
Many thanks in advance.

Colin

WRe

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Re: Valve Stem seals
« Reply #1 on: May 31, 2024, 17:07:26 »
Hi,
I did this job 2 years ago but with the cylinder head installed: https://www.sl113.org/forums/index.php?topic=35592.msg259885#msg259885.

Material: There are different kits on the market. OEM manufacturers like Elring or Viktor Reinz are identical. Unlike my old white nylon/wire seals, the new ones for the exhaust valves were brown Viton like yours. Other kits are all white nylon.

Seal groove: The later guides have seal grooves like yours. The early guides not. These had problems holding the seals in place.

"Lower seal": There is no lower seal, Haynes is wrong. They show a rotocap that turns the valves.

...WRe



colin evans

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Re: Valve Stem seals
« Reply #2 on: May 31, 2024, 17:17:12 »
Hi, thanks.
Just to be clear, because as you can see from the pic that there is definitely no seal present in the groove, there should be a seal in the groove at the top of the exhaust guide that the main stem seal slides over? Is it ok to fit the white plastic stem seals on inlet and exhaust?
Regards
Colin

WRe

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Re: Valve Stem seals
« Reply #3 on: May 31, 2024, 18:09:19 »
Hi,
The valve stem seal is the seal, there is no other seal (in the groove). The groove holds the seal in place.
The new all white seals are teflon seals and should be ok.
https://www.w113.eu/geschlossen/Reparaturen/Ventilschaftabdichtungen Mercedes Pagode W113.htm.
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colin evans

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Re: Valve Stem seals
« Reply #4 on: May 31, 2024, 18:30:23 »
All clear thanks. Just out of interest what is the 1020530358 seal for?

WRe

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Re: Valve Stem seals
« Reply #5 on: May 31, 2024, 20:35:56 »
9mm seal for outlet valve for many MB cars from mid. of '70.