Results 1 to 2 of 2

Thread: Lead substitute

  1. 07-17-2003, 07:24 AM #1
    87 Sunsport
    87 Sunsport is offline Member
    Join Date
    Apr 2002
    Posts
    91

    Default Lead substitute

    I've been faithfully adding lead substitute to my 87 Sunsport because both the manual and the PCM manual says I should.
    I just read a thread elsewhere that says it's useless in any engine build before 74, something about hard vs soft valve seats and the fact that the substitute doesnt do anything anyway. Any one know the truth on this?
    Reply With Quote Reply With Quote
  2. 07-17-2003, 02:06 PM #2
    John D
    John D is offline Junior Member
    Send a message via AIM to John D
    Join Date
    Jul 2003
    Location
    hamilton, ontario, canada
    Posts
    5

    Default lead substitute

    I have an 84 comp. I wrote PCM about this very question and they said it depended on what heads you have on the motor. If the heads are prior to 1974, the motor does not have hardened valve seats and requires the lead substitute. If the heads are newer than 74, the valve seats are hardened, and the substitute is "optional". How do you know what you have? If the spark plugs use a 5/8" wrench, you have the new ones. If the spark plugs use a 13/16" wrench, you have the old ones. Note: give me a fax number and i will send you the letter.
    John D
    John D
    Reply With Quote Reply With Quote
« Previous Thread | Next Thread »

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Forum Rules