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Im in a tough spot and hoping that that someone will teach me up real quick...
I replaced the plugs (first plug change and she was running fine - if it aint broke - comes to mind) with these: https://rover.ebay.com/rover/0/0/0?m...2F352472478366://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F352472478366
They are pre-gapped at .040,,,, and I foolishly just popped them in.
Im reading that .028 - .032 is correct. I am having stalling, a bouncy idle and a really rough ride. Can this difference in GAP really be the culprit? I'm away form home, with my lady (feeling a little silly) and have a funky/unreliable running car... I'm prepairing to go and get the things I'll need to do the work where I am.
REAL QUESTION --- Because of the DESIGN of these plugs - the gap and electrod ends seem very percisely lined up - will gapping them distort that jump space and mess things up further? Do I just gap them like a normal plug? HEEEELP, lol
I need of real help here... Anyone?
Last edited by JayPoorJay; 05-04-2019 at 12:53 PM.
I am sure others with more experience will chime in, but if I am not mistaken the gap is dictated by the ignition system and engine parameters not by the brand of plug.
So if you are running badly at .040 then I would suggest going to the factory specification would be the next step. Easy to do to verify if it makes a different or not. You should have all the tools on board except perhaps for a gap tool.
with an old style distributor system you need a tight gap because the spark is relatively "weak" after already jumping from the cap/rotor.
on more modern distributorless systems they can open the gap up to 0.060" or more because theres so much more spark energy available, concentrated and controlled.
so yes, you are WAY off with your gap which could be causing your problems. your fire is going out before it can catch...
Is that eBay link correct, you installed Denso 4502 plugs? If so those are platinum plugs, you want copper plugs in a 928.
The proper plugs for your 928 are Bosch WR7DC (the C stand for copper) or the equivalent from other brands.
Give 928 International, 928's R Us, or 928 Specialists a call and they'll set you up with the correct ones. Or stop down to your local auto parts store, these are very common. Just don't let the people behind the counter insist on asking what kind of car since their computer will say platinum plugs are correct.
So the plugs I have (for now) are the ones I will have to use. Given that,,, the re-gapping questions I've asked,,, can I regap and keep it moving... It's what I kinda have to do at this point.
Last edited by JayPoorJay; 05-04-2019 at 03:19 PM.
Given no other choice, I don't see why regapping wouldn't work.
Platinum and iridium plugs simply last longer. Copper plugs tend to work better with older systems because copper is more conductive but I don't think that difference would be a big deal unless you're really pushing the engine.
Hello All. Thanks or allof you input and replies...
Damned-est thing... I cannot believe how sensitive she is! So yes, I worked with the plugs I have - all I could do... Removed them all in a parking place in Brooklyn (people really do notice the car!), re-gapped and replaced. And yes, .028 to .030 as opposed to .040 does apparently make a difference. A big ol difference. So does my new handy dandy tool (flexing extension) with a real spark plug socket. I wont even describe the loooong and tough process I was using before this - included a mgnet and,,,...
She runs well but idles a little lower and gets a little funny with a pretty extreme RPM drop when I push in the clutch at running speed for a light and stops, and such. Then the idle will bounce a second or two. No good.... I worry about that. But for now,,, reliable and smooth runnng when up and going along which is much much better than what was happening before...
I know its and 86, has a computer, will she learn and set herself to the new plugs? Does a 1986 Porsche ECU learn?
Do yourself a favor and your car - use the correct plugs for the car - as already said WR7DC+. We sell for $2.75 each and I am sure the other 928 savvy suppliers do the same.
Gap 0.7mm 0.0275" + 0.1mm .003"
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Do yourself a favor and your car - use the correct plugs for the car - as already said WR7DC+. We sell for $2.75 each and I am sure the other 928 savvy suppliers do the same.
Gap 0.7mm 0.0275" + 0.1mm .003"
Thanks Rog.... This problem won't go away. It's pretty bad and changed my day... I just emailed ya...
I haven't cross referenced that plug, but it's possible the heat range on that plug also isn't right for the 928 and contributing to the issues even though you now have them gapped more correctly.
Yeah... I think the specs said the heat range is 20... "Heat Range" is a whole new concept for me. Learning here.
I think I'm going to take (and should take) Rog's advise and just stick with what is known to work... I like the "knowns"...
Reminds me of the Rumsfeld video, lol. The known knowns, ya know?
Last edited by JayPoorJay; 05-05-2019 at 05:00 PM.
05-04-2019, 12:31 PM
Spark Plug Gap - EMERGENCY
George Layton March 2014
