Author Topic: Valve guide material ?  (Read 1244 times)

1960mog

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Valve guide material ?
« on: 07 June 2016, 12:06 PM »
Hello

I need to make new exhaust valve guides for my 6.9.
Anyone has any recommendations what material to use?
Or even better, anyone knows what alloy Mercedes used for the original guides?

Thanks
« Last Edit: 07 June 2016, 04:12 PM by 1960mog »
78 6.9 #4084
79 6.9 #6669

daantjie

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Re: Valve guide material ?
« Reply #1 on: 07 June 2016, 12:27 PM »
Try these guys they have a bunch of NOS stuff:
sean@exoparts.com

Best to have part number handy:

100 050 5624

Sean Lowry from Exoparts based in Eastern Canada.

Have you checked with the Classic Centre in Irvine California?
« Last Edit: 07 June 2016, 12:33 PM by daantjie »
Daniel
1977 450 SEL 6.9 - Astralsilber

rumb

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Re: Valve guide material ?
« Reply #2 on: 07 June 2016, 01:12 PM »
Should be able to get at dealer for @$25 each.

'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

1960mog

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Re: Valve guide material ?
« Reply #3 on: 07 June 2016, 04:10 PM »
Should be able to get at dealer for @$25 each.

Being able to buy them, and being able to pay for them, are two different things.
Especially now, that I have two 6.9s. 
I can buy a lot of material for $200, just need to know what to buy.
78 6.9 #4084
79 6.9 #6669

ptashek

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Re: Valve guide material ?
« Reply #4 on: 07 June 2016, 04:47 PM »
As far as I know, Benz valves are made out of high-nitrogen stainless steel. I remember reading about it somewhere in their docs about unleaded v. leaded fuel use.

Given the operating conditions of the 6.9, that'd be most likely 21-2N or 21-4N steel. If so, the guides may be Manganese-Bronze.
That's all I remember from one of my materials science classes years ago, and I wasn't an A-club student either ;)
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1979 "Icon Gold" W116 450SE (history, resto)

UTn_boy

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Re: Valve guide material ?
« Reply #5 on: 07 June 2016, 10:22 PM »
The early guides were much softer than what is available today.  So during your research, make sure that you find what is needed for the modern guides. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex
1978 450sel 6.9 Euro, Anthr/velour

1960mog

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Re: Valve guide material ?
« Reply #6 on: 08 June 2016, 05:45 PM »
Looks like Manganese Bronze is the way to go.
Just have to figure out what flavor to use.
Powdered metal is the other option, but seems to be harder to obtain.

Thanks for all your help guys.
78 6.9 #4084
79 6.9 #6669

TJ 450

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Re: Valve guide material ?
« Reply #7 on: 12 June 2016, 07:31 PM »
I'm in the process of having the heads on mine rebuilt now. The guides are indeed a soft bronze material. Anything harder and it will not be kind to the valve stems at all.

Btw valve train noise due to worn valve guides seems to be an issue on certain 6.9s, on mine all the exhaust valves were slapping around creating a loud noise, all the intake valve stems were worn too. Yet there was very little oil consumption.

Regards,
Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

daantjie

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Re: Valve guide material ?
« Reply #8 on: 12 June 2016, 08:24 PM »
Yup this is well documented and unfortunately a trait of Benz valve guides from this era. Perhaps other manufacturers too. I had an intermittent tapping which turned out to be a worn exhaust valve guide. Not sure I want to commit to pull the heads on my 6.9. It is a massive job and not cheap  :o
Daniel
1977 450 SEL 6.9 - Astralsilber

1960mog

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Re: Valve guide material ?
« Reply #9 on: 13 June 2016, 05:13 PM »
I can't say anything about oil consumption, I was never able to drive the car.
While changing valve stem seal I noticed the worn exhaust guides. 
The intake guides are still fine.
78 6.9 #4084
79 6.9 #6669