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Spark Plug Extenders ... Opinion

Discussion in '308/328' started by 76Steel, Dec 30, 2008.

  1. 76Steel

    76Steel Formula 3

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    #1 76Steel, Dec 30, 2008
    Last edited by a moderator: Sep 7, 2017
    Hi everyone,

    Here is another ine for little Ferrari gremlins. On 2 occasions someone washed my car as a courtesy and water has gotten into the spark plugs due to the old rubber plug boots .... - I have since bought a new set of those.

    However, when checking the spark plug extenders (see pic) ... I noticed the steel part inside that goes on top of the spark plug being a slight little rusty/ little white sedimented. I am assuming this happened after the two car wash incidents, etc. The damage to the extenders is not big and overall they are in good condition - no cracks, nothing bent, etc, but I can not help to think that it does not help the connection of the spark plug..

    Question ... can this light rust or most likely a white sediment be cleaned off with a small wire tip instrument/ brush ... or am I looking at nother part to buy.

    Thanks for any who will chime in.
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  2. 308GTS

    308GTS Formula 3

    Dec 27, 2001
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    I know exactly what you mean. It would happen on my 78 308 all the time. I would take them out and get a little sand paper and put it on my finger and clean it. They worked fine for years. I had to do this every so often but the extenders are fine.
     
  3. Verell

    Verell F1 Veteran
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    Get some grey (very fine) Scotchbrite, & clean them up, then give them a very thin coating of dielectric grease. They'll be fine.
     
  4. 4re308

    4re308 F1 Rookie

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    Always watch out for a grounding spot in the inside and outside of the ceramic. Usually at the bottom. That is the only problem I've had with those extenders. Also be aware that the black extender is for the early 308 cars and the red extender (which is a few mm shorter) is for the 3.2 cars.
     
  5. RichardAguinsky

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    Is there a procedure for testing these extenders for internal dielectric/continuity problems? I couldn't find it on line. Thanks,
     
  6. CliffBeer

    CliffBeer Formula 3

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    The main thing with these extenders is to simply keep the contact surfaces clean (sometimes you just have to replace them as it's difficult to clean the inside contact) and keep an eye out for burn throughs. If you haven't seen a burn through yet it looks like a very small pin hole with very fine carbon dust surroundig it. I think a lot of 308 owners would be surprised to see the amount of shorting that can go on inside the valve cover recesses for the plugs when the extenders haven't been replaced in a few years.

    It is possible to make the rubber boots from 3.2 wires work on a 308, however, I believe the 308 valve covers lack a lip around the recess to locate the boots really positively. In any case, it's an improvement when it comes to keeping moisture out of the recesses.
     
  7. ClydeM

    ClydeM F1 Veteran
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    My '83qv 308 has Black extenders: put on by a Ferrari shop. From old threads, I believe it's impediance more than the color. I don't recall seeing anything about a length difference.
     
  8. davehelms

    davehelms F1 Rookie

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    Anything short of a polished surface inside the extenders will eventually lead to their failure, look at the gloss, ribbed surface of the older performance coils, sparkplugs.... as a guide. Even the clean, rough, random surface of the plastic is better than one with straight line micro scratches from sanding them.

    Micro scratches from sanding in any way will collect dust and dirt and hold it in a straight line. Collect enough and add a little moisture and you have a carbon track that the spark will follow rather than jump the gap at the sparkplug under the high pressures of the combustion chamber. Add a couple of high resistance plug wires to the mix where the spark voltage goes high and they will all start failing. Loosing proposition to try to revive or service these in my view.
     
  9. 76Steel

    76Steel Formula 3

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    #9 76Steel, Jan 1, 2009
    Last edited: Jan 1, 2009
    Verell,

    You mean - Scotchbrite - cleaning pad the ones that are commonly used in kitchen/ bathroom?
     
  10. 76Steel

    76Steel Formula 3

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    Also guys, if the plugs got water and the water stayed there for a few weeks (by the plug) (mind you not a lot of water) ... could this cause some rusting?


    Which lead to a question -- Is it time for new plugs as well?

    Many thanks,
    Mike
     
  11. fastradio

    fastradio F1 Rookie
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    +1000!

    Having spent so much time with "perfectly running" cars that have an odd, occassional mis-fire, yet "all parts are new, so says the onwer of previous shop", the mere thought of any repairs or mods to improve performance of "suspect extenders" are simply a waste of time and money. That's not to say that all extenders need to be automatically replaced; however, just because they pass an ohm test doesn't mean they're any good either.

    On a recent 328 major service, I tested the extenders:

    One tested "open" circuit
    Seven tested "within specs", although one did had a chunk of plastic missing where it snapped on to the spark plug...

    However, of the seven electrically good (ohm-test wise) extender, the other six, that were not broken, either had severe corrosion on either the plug or boot end and/or had minute "pin-sized" arc through marks on them. Needless to say, the plug wires were also tested and found to be in equally poor condition. (Keep in mind that these components were on a real 12K miles car that had had a bonefide very reputable Dealer major service done seven years ago).

    Yes...this car "didn't run too badly" and "did idle a bit rough" as I was told "they all do"...Hmm...really?

    In my opinion, these extenders are truly a "throw-away" part that should be replaced at every major service and/or anytime any damage is seen on them.

    Then again...chasing mis-fires may be someone's idea of fun?
     
  12. RichardAguinsky

    RichardAguinsky Formula Junior

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    I'd like to replace the extenders, cables, rotor and possibly distributor cabs in the major I am about to start. Any place I can get these at a reasonable price? Prices on the web are all over the place, a distributor cab ranges from $100 to $600
     
  13. FF8929

    FF8929 Formula Junior

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    I'd check Dennis McCann.
     
  14. moretti

    moretti Four Time F1 World Champ
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    #14 moretti, Jan 1, 2009
    Last edited: Jan 1, 2009
    get a set for well under $100 from Superformance

    I had an intermittent misfire for ages in the QV until I noticed a small pinhole in the extender shaft where the tip of the sparkplug would be which was arcing out to the cylinder head, water of course making it much worse

    for the sake of AUD$80 I have fixed the problem and the car has run very sweetly for years now.

    BTW get a RED set, not for asthetics but because it will show up this arcing whereas the black ones won't and you can beat your head against the wall for ages.

    I had a black set and a red set, both had the same arcing problem in 2 different cars, the red set I found the problem in a couple of days due to the arcing making a black mark on the outside of the extender, the black ones I found by trial and error
     
  15. M.James

    M.James F1 Rookie

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    Its my understanding that you cannot 'mix-n-match' the plug extenders for different-year 308 cars - the plug wires themselves were ohm-matched with the correct type of plug extenders, creating a circuit with the appropriate Ohm rating from the coil packs to the spark plugs. Mixing QV/3.2 plug extenders (the RED ones) with OEM Carb/FI- rated plug wires causes problems, so I've read on other threads. I recall something to the effect that if you use low-ohm rated extenders, you need to use higher-ohm wire or vice versa - anyone care to comment on numbers?
     
  16. davehelms

    davehelms F1 Rookie

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    #16 davehelms, Jan 2, 2009
    Last edited: Jan 2, 2009
    All came about by someone shopping for these aftermarket and looking only at the length. All OEM extenders came with zero resistance extenders on the 3X8 (I limited it to that as I just dont remember if one of the early Boxers had a resistance type and there are a vfew exceptions such as the F40's) based models. Length was the only difference between the 3 options available. Plugwire should be 350 ohms/foot with zero ohms extensions. Measure resistance through the cap terminals to the end of the extension, calculate the length and verify the readings you get.

    The single most overlooked issue in this area is the reading through the cap terminal. The pointed screw HAS to have physical contact with the core wire or you have an open circuit in that area. Pre 348 plug wires were all of a Spirocore, single conductor wire design where a .003" conductor was wrapped around a central fiberglass core. This is where the OEM and most aftermarket wires fall short with the loose wound conductor wire and the reason I had the huge spool of the 7mm Taylor wire made for me. The pointed screw has a tendency to push aside the loose wound conductor wire, where the Taylor wire is embedded and held in place so there is always two or three windings in contact with the screw. Any gap between the screw and the conductor in this area will create an arc and it doesnt take that long for a .003" diameter conductor wire to arc through and then go open circuit. Run with an open circuit or high resistance and the coil raises the spark voltage and then the extensions have to deal with voltages outside of their design parameters. Run with high resistance on one wire and the others on that bank then have to deal with the increased voltages and will then fail one by one. Its a big snowball at the top of a long hill.

    The systems will tolerate higher resistance levels than what they were designed for but resistance is just that and the voltage's are effected and will find the next weak link in the chain. There are reasons why things fail, turn over enough rocks and the answers are there, so are the solutions. It was all designed as a package, those extensions are not all that bad so long as they are used within the parameters they were designed for.

    Dave
     
  17. Mike C

    Mike C F1 Veteran
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    #17 Mike C, Jan 2, 2009
    Last edited: Jan 2, 2009
    I was told that if you use resistor plugs or wires, you need one type (color) of extender... if you don't, you need the other. I don't remember which is which.
     
  18. Verell

    Verell F1 Veteran
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    #18 Verell, Jan 3, 2009
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    Dave,
    I'm confused as this doesn't match my (admittedly limited compared to yours) experience.

    We had a round of extender discussion & actual dissection back in 2001, it's in the old fchat archives:

    http://www.ferrarichat.com/discus/messages/256120/134699.html

    Unfortunately, the pictures I posted to the thread didn't survive the hard drive crash, but I still have them & am posting them here.

    The red extenders that came on my '82 Euro 308 QV were definitely resistor extenders, measuring 4K ohms. When dissected you can clearly see the black resistor cylinder(2nd pic). From the old post:

    I believe these were my car's original extenders, but can't prove it: While I don't have service documentation, the car came to me in 2002 with low mileage & CARFAX data shows that only about 2K miles had been added since 1992! These red extenders have a logo that looks like: MAfER inside a raised border, The 'f' is an elongated narrow vertical double curve with a very small horizontal hash mark in the middle. I've seen this logo on some black extenders & that the owner believed were OEM, and claimed he had complete service records to back it up.

    At the same time, I also purchased a set of red extenders w/o logo markings that came labeled with the Ferrari logo, the Ferrari P/N, & the words "CON RESISTORE" from one of the aftermarket distributors. They definitely all measured 2K ohms(1st pic).

    Some black extenders I acquired before I located the red ones measured 0 ohms.
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  19. Steve Magnusson

    Steve Magnusson F1 World Champ
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    A prior thread for reference that shows that the color of the extender has no direct relationship to the resistance of the extender:

    http://ferrarichat.com/forum/showthread.php?t=212698

    Maybe it did at one time, but it doesn't anymore -- use an Ohmmeter to know what you have!
     
  20. Verell

    Verell F1 Veteran
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    OK, so now we've got to measure the extenders, & it sounds like we're most likely to get 0 ohm extenders.

    Which spark plug type do we use with them?

    The understanding back when I was watching the extender discussions was either you had a resister extender & non-resistor plug or vice versa, but not both the same. ie:

    Extender____| Spark Plug
    ---------------+-------------
    Resistor ____| Non-Resistor
    Non-Resistor | Resistor

    David,
    Which plugs do you use with your Taylor wire & 0 Ohm extenders?
     
  21. davehelms

    davehelms F1 Rookie

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    Well, pictures and first hand experience doesn't lie. These could be the Euro extenders I have heard of but have not seen prior to now, a few MM longer if I remember what I was told correctly. I had no idea they were resistor and can see now advantage to having one in this application considering the plug wires they came with. Were they used on solid steel core wire or did they see fit to use the Cavis resistor wire along with a resistor end? Resistor wire with a resistor end would be over the top ridiculous.

    I stand corrected, my apologies.
     
  22. Verell

    Verell F1 Veteran
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    #22 Verell, Jan 3, 2009
    Last edited: Jan 3, 2009
    Good question Dave,
    I agree, restor wires + resistors in either plug or extender doesn't make sense.

    Yes, the original extenders were slightly longer than the replacements I've got.

    Never measured my wires as my car's always run extremely well with a very smooth idle except when one of the extenders had burned thru. I've always assumed I had solid wires as ignition noise plays He## with my radio & I've never gotten around to trying to do anything about it.

    However, looks like I was wrong. I've got the distributors & wires off for my SC project. I just went out & measured some. They seem to be resistor wires! A long wire measured 1200 Ohms & a short one 780 Ohms, pretty close to your 390 Ohms/foot. Another one measured open so good thing I checked them!


    BTW, IIRC my original plugs were non-resistor Champions.
     
  23. luckydynes

    luckydynes F1 Rookie

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    The more you check 'em, the more you'll find bad ;). I got tired of re-doing the connection in the dizzy ... I checked them even though the car was running fine and was constantly finding "iffy" connections especially when I'd wiggle the wire in the cap like your hand will do if you're working on anything in that area .... the coil on plug conversion eliminated all those headaches :).

    Cheers
     
  24. davehelms

    davehelms F1 Rookie

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    #24 davehelms, Jan 4, 2009
    Last edited: Jan 4, 2009

    I broke my own rules...never say never in this game!! I have heard about the Euro extensions but obviously have not run across them. I wonder what the thinking was...I never heard of any solid core wires on these cars but hey, I have been proven wrong already. A few MM longer for what reason? Wonder if they were testing a new suppliers product where a part already existed on the shelf that was close. Is yours an early car?

    The Spirocore design wire is very good at canceling out the RFI by nature of its design. The RFI has been found to be the cause of many almost imperceptible issues with the Digiplex cars, small shudders here and there...things so vague many don't really show up on the radar until they go away...Then you feel it!

    Back in the early 80's while trying to fit twin MSD's to the 250 race cars I learned just how important an issue this RFI was and how well the spiral core design works in this application. Cavis was ahead of their time in design but dropped the ball when they stuck with 70's technology materials all the way to present. Then again, at $1000+/bank on the TR's until recently with a short lifespan...who's the fool? Bet the shareholders disagree with me!

    Your right Lucky, the COP is the technical end all be all solution, just cant get my arms around the looks on these cars.
     
  25. luckydynes

    luckydynes F1 Rookie

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    That's okay ... I can understand that ... you get paid to constantly fix that stupid connection in the cap ;) LOL (totally joking).

    One other comment on resistor plugs/RFI ... when I was trying to get the coil on plugs working I almost gave up after a few calls to typical support lines ... car wouldn't rev over 4k ... was ready to send the DIS4 box back to MSD. Then the RFI thing dawned on me and I switched to resistor plugs and problem went away ... what a joyous day/weekend that was :) :).

    Anyone seen the Borg Warner "Nascar Lifetime" plug wires? They are also spirocore. With the correct wires/core do you find this connection "rock solid" or is it as finnicky as I experienced? My stocker 308 has what appear to be new "factory style" wires & caps but had bad connection issues when I checked them with an ohm meter and re-doing them wasn't something I was excited about from past experiences .... so there she sits ... as I contemplate EFI, supercharging, or keeping the CIS and building just the internals ... decisions, decisions :).


    Cheers,

    Sean
     

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