Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

87 3.2 high carbon buildup 7000 mi. since valve-job


jmeckles

Recommended Posts

Bought a 87 911 at 87000 mi that I knew needed a valve job (high oil consumption) which was performed by reputable shop. Work included new valve guides, exhaust valves, etc.  Car exercised weekly at all speeds / conditions and put on dyno after 6 mos later when it pulled anticipated BHP and torque.  Now, (3yrs and 7000 miles later) it began running cumulatively more and more poorly. 

 

Diagnosis including a cylinder leakdown test and borescope review, found 5 cylinders have above 80+% leakage from exhaust valves and a very high carbon buildup on intake, exhaust valves and in combustion chambers.  Two unrelated shops have diagnosed by leakdown tests with same results.  Logically, it will need teardown to determine cause of problem.

 

All thoughts and comments are appreciated particularly considering the short time since the valve job.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.