Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 02-15-2006, 07:03 PM
Registered User
Join Date: Jul 2003
Posts: 528
valves new or used?

How do you determine if you shouild re-use the existing valves or install new ones, specially on fouling cylinder.

Thanks, Juan
Reply With Quote
Old 02-15-2006, 07:34 PM
t walgamuth's Avatar
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 34,741
a machinist can measure

the edges and see how worn they are. if not too worn they can resurface them and go. on a diesel the exhaust take a beating and often the intakes are good even after 200k miles.

tom w
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
Reply With Quote
Old 02-15-2006, 07:37 PM
Registered User
Join Date: Jul 2003
Posts: 528
Thanks, what does it mean a burnt valve? Is actually a valve that has a section burnet away, edge wise or carbon buildup on a valve?
Thanks, Juan
Reply With Quote
Old 02-15-2006, 09:48 PM
Registered User
Join Date: Sep 2004
Location: Seattle
Posts: 1,932
A section burned away. Always an exhaust valve AFAIK. It leaks so you have low or no compression in that cylinder. Often exhaust valves have to be replaced but not intake, in my limited experience.

1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra
Reply With Quote
Old 02-15-2006, 10:51 PM
Registered User
Join Date: Jul 2003
Posts: 528
Thanks for the info, the exh valve has carbon build up but nothing burnt away. compression was ok.
Thanks, Juan
Reply With Quote
Old 02-15-2006, 11:23 PM
Registered User
Join Date: Mar 2003
Location: Southern California
Posts: 2,142
You should also carefully mic the valvestems. If the wear is close to or exceeds .001" the valve should be replaced.

Reply With Quote
Old 02-15-2006, 11:28 PM
Registered User
Join Date: May 2003
Location: bullhead city, az hot as hell
Posts: 301
I agree with duke, measure at the top and bottom there should be very little taper, look for pits and grooves were the valve sits on the seat
Reply With Quote
Old 02-16-2006, 01:20 AM
Registered User
Join Date: Jul 2003
Posts: 528
thanks guys.
Thanks, Juan
Reply With Quote
Old 02-16-2006, 09:59 AM
Posts: n/a
Valves rarely burn in a Diesel engine.

I have indeed seen a burnt intake on a gas engine. It was a 56 Ford with a leaky intake manifold which leaned out one cylinder burning the intake valve at that cylinder.

Your machinist will be able to tell by looking at the valves if they can be reground or not.

Good luck,
Reply With Quote
Old 02-19-2006, 01:34 AM
Registered User
Join Date: Jul 2000
Posts: 638
re-use valves or replace?

Not at all unusual for intake valve stems to be worn out on a MB diesel. The valve does not rotate (it is held in a fixed orientation by a pin sliding up/down in the guide to keep the intake shroud oriented.)

Wear is th econsideration, and how the engine will bedriven. Racing purposed argues for all new. Normal operation (anything less than WOT and redline) means reused determined by condition--worn stems, worn spring keeper grooves, warped, pitting, top too thin after re-surfacing--all mean use new one.

Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 10:35 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page