Page 2 of 2 FirstFirst 12
Results 16 to 17 of 17
  1. #16
    Member LLC5's Avatar
    Join Date
    Sep 2004
    98 black 6spd convert.
    Post Thanks / Like


    Glad to hear you got it, good job.
    Master Technician

    25+ year ASE Master Certified Tech

    22+ year Honda Master Tech
    Likes Frankio `88 Coupe liked this post

  2. #17
    New Member
    Join Date
    Jan 2020
    Mid Hudson Valley NY State
    1988 Black Coupe Auto Z52 17k Miles
    Post Thanks / Like


    Quote Originally Posted by 89C4KB View Post
    I recently purchased a 1989 Coupe with 42,000 miles. It did not come with any service history. It currently has a minor vibration from the engine at low to mid rpms. It goes away and runs hard when I get into the throttle. I pulled the air filter and found it was black. Judging by this I feared what else I might find. As much as I was scared, I pulled the diptsick and found the oil looked like it was put in the week before. I am fairly certain the the plugs, plug wires, rotor and distributor cap are all factory (based on the mileage).

    This is why I am starting at the air filter and working my way back to the distributor with new parts. That said, I picked up a set of ACDelco Rapidfire 5 plugs (ACdelco part number 19308030). Guy at the parts store told me those were the correct plugs for the vehicle and they were pre-gapped. I got home and found all the plugs gapped at .043. Then I pulled out the vehicle manual and found the specs call for .035 gapping.

    I proceeded to gap all of the plugs to .035 then went to bed. The plugs are still on the work bench. When I woke up I had a bad feeling I was sold the wrong plugs due to the consistent gapping they all had. I started searching forums, here and elsewhere, and found these plugs are correct for my vehicle. Further reading showed people running these plugs gapped anywhere from .035 to .050 with good results.

    So bottom line is...I am going to install these plugs tomorrow and don't know what I should gap them at. I am thinking of gapping them at .040 to split the difference of everyone else's experience with these plugs, and see what happens unless I receive information to the contrary.

    I am a first time Corvette owner so please start yelling at me if you see something horrible with this plan.

    I know this is an "old thread" but being I just swapped out all the plugs on my `88 L98 - I noticed all the new plugs out of the box were gapped at .040 -.045 using my machinists calipers. I checked my handy ring gage gap tool and the .035 mark was off a few thousands undersized so I had to re-gap all he plugs by tapping hem a bit to close the gap a couple of thousands. I know I'm nit picking but I am a retired machinist/machine shop manager so these things bother me. I like perfection (to a a fault sometimes) but I think anywhere between .035 and .040 is probably good enough for horseshoes !

Page 2 of 2 FirstFirst 12

Similar Threads

  1. Spark Plug (Coil-On-Plug) Boots at RockAuto.com!
    By RockAuto in forum Parts and Accessories
    Replies: 0
    Last Post: 01-12-17, 11:58 AM
  2. Changing spark plugs and spark plug wires.
    By Corvsinis in forum C5 Technical and Performance
    Replies: 20
    Last Post: 04-27-16, 08:51 PM
  3. What is the best spark plug for 327 ?
    By Wayne64 in forum C1 & C2 General and Technical Discussion
    Replies: 6
    Last Post: 08-27-07, 04:21 PM
  4. What is the best spark plug for LT1?
    By racersedge52 in forum C4 Technical and Performance
    Replies: 2
    Last Post: 04-13-03, 10:56 AM
  5. MSD Spark Plug Gap
    By Buckskin7T7V in forum C3 Technical and Performance
    Replies: 6
    Last Post: 06-26-02, 07:37 AM

Tags for this 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