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
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?
Should be able to get at dealer for @$25 each.
Quote from: rumb on 07 June 2016, 03:12 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.
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 ;)
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.
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.
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
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
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.