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 > Mercedes-Benz SL Discussion Forum

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 04-04-2006, 03:43 AM
Bondavi's Avatar
Registered User
 
Join Date: Feb 2005
Posts: 316
Valve job: To do or to avoid?

I have the intake manifold off of my car to replace gaskets and have been thinking of undertaking a valve job by removing the heads and having a professional do them. When do you know a valve job is needed on these M117 engines? I know the guide seals could stand being replaced, and these can be done with the heads still on the car. However I might want to do it all while I have the car in pieces for preventative maintenance. If this job is being done, I will be doing the chain and guides as well. The car has about 120K on it, no smoking as far as I know.

When pulling the intake manifold bolts, mainly in the back, some were rusted and had black soot on them. Indicator of something?

Also, replacing the chain and guides with the heads off of the car doable and with every day tools, not high-zoot Mercedes "special tools"??

Reply With Quote
  #2  
Old 04-04-2006, 07:57 AM
Super Moderator
 
Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,318
Leave well enough alone

If you have no problems, leave the heads on. It is a lot of work and expense (probably $800-900 at the machine shop). There is a lot of bad stuff like broken exhaust bolts/studs and stripped head bolt threads that can happen.

You would need to remove the rails to get the heads off. This requires a screw or impact puller to get the pins out. You will also need a valve spring compressor that hooks under the cam. There are several places that sell these (AST and Samstag Sales come to mind).

Lots of posts on this.

The rust and soot is normal IME.
__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
Reply With Quote
  #3  
Old 04-04-2006, 11:46 PM
88Black560SL
 
Join Date: Oct 2004
Location: CT
Posts: 3,510
I would be more concerned with a leaky head gasket than with valve guides. Do you absolutly have no drip coming from the back of the engine looking like it maybe leaking at the rear main seal?. Is the left back side of the engine wet from an unidentifiable source.

I had a leaky head gasket at 105K miles. Everything else was fine so I just replaced the left head gasket only. I did retorque the right head gasket which was a very scary job since they have a habbit of stripping. Some of the bolts on the right head tightened up almost an additional 1/4 turn.

If everything is running fine and no oil cunsumption or leaks dont mess with this. At 120K do replace chain, 3 upper chain rails and tensioner rail liner. Also replace cam shaft oil tubes.

If you are not familiare with this job, I recomend you buy the rail pin puller tool and the chain installation tool. I'v always managed without them but others have not been so lucky. See some of my past posts from about 1 year ago. By doing this job yourself you will be saving about $1000 so whats $120 worth of tools. Also there is a tool rental forum on this web sight. I'm sure someone has these.

If you decide to go for the heads, be prepared to install inserts, which requires a $1600.00 drill guide tool or you can probably make your own out of a set of scrap heads. Some of the head bolts ar at a slight angle from perpendiculare.

Good Luck
John Roncallo
Reply With Quote
  #4  
Old 04-05-2006, 12:28 AM
Strife's Avatar
General Purpose Geek
 
Join Date: Apr 2004
Location: KY USA
Posts: 2,238
I agree with the above post entirely. There are also a lot of hidden costs in the heads. Gaskets add up to a lot of money, and who knows what you will break or strip. The head bolts are very scary, I've read. MB says they NEED to be helicoiled if the bolts are removed. Many have gotten away without doing this, but some have not. I beleive that the guide tool has the holes drilled 1 degree off from the original line of the bolt!
__________________
86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm
Reply With Quote
  #5  
Old 04-05-2006, 01:40 PM
Registered User
 
Join Date: Jul 2003
Posts: 555
If it ain't broke leave it alone. Spend the mone y on gas and drive.

__________________
Thanks, Juan
Reply With Quote
Reply

Bookmarks

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 09:39 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page