Spark plug boots

[William C.]

Re: Spark plug boots

OK, you have forced me to take some pictures, note the date this is a 1966 example, however the parts were all the same 1962-67 and beyond, how far beyond would take more time than I have right now. The first picture is from the side agains a rule, note how much shorter the boot is from the front to the back than the repro. The second shows typical dating and also the rib that runs from the cable entry around the front and back the opposite side that is missing from the reproduction. Also in the second picture you can see some bumps on the bottom that would be facing the sparkplug base. These were a result of the rubber entering the mold from that end and were seen on all original boots thru the era. So, size, missing rib, missing signs of processing nubs, anything else?

[William C.]

Re: Spark plug boots

These look just like the earlier ones, see my pictures from '66 the nubs were lost along the way do to equipment upgrades in the molding system in the 67-68 timeframe. Yours has a little nub on the top, mine had an indent, that is normal variation in how much of the runner was removed. Believe it or not, many of these small rubber parts were molded and came out of the mold attached to a mat of material that was leftover from the transfer process. They them went into a cryogenic tumbler that froze the parts and tumbled them to remove the excess material, then they were washed and lubricated to allow them to be processed onto the wires. Quite a lot of work at about 200,000 per day, every day!

[Jim S.]

Re: Spark plug boots

"So, size, missing rib, missing signs of processing nubs, anything else?"


Other than that , they look like originals , Right !!!

lmao. Thanks Bill,

Jim

[Mike E.]

Re: Spark plug boots

Clup,
Please also explain how the boots were molded. My original 62 wires, if you recall, had 5 or 6 "tits" along the end of the boot on the spark plug end, and you explained their presence.

[William C.]

Re: Spark plug boots

The original process was a transfer mold process where a sheet of material was placed into the bottom of a mold with a plate on top of that having the small openings into another plate above with a third plate forming the top at about the rib level. This was about the fall of '63 when I worked in the area for a while, but the (uncured) rubber was heated to a melt the forced thru the small holes in the bottom into the cavity above, where the rubber cured then the mold was disassembled the remaining material in the lower area disposed of and the parts removed and inspected, and deflashed as necessary (cryogenic tumbling and wash) Later, inproved technolody was introduced that eliminated the transfer process instead using a direct injection I believe thru the top, although by that time I had graduated from college and was nowhere near the hot & dirty rubber molding facility. One of the reasons the boot entrance area where the wire exits was so short was due to the assembly process. Terminals were attached to the cable at a direct 90 degree angle, then the boots were placed on a pin to straighten them out them and pneumatic assist simply pushed the boot over the wire terminal and the wire. Quite a process! I think the late 60's is when the transition to the more modern technology of molding eliminated the nubs on the bottom, although it would have happened over a fairly long period of time.

[Timothy B.]

Re: Spark plug boots

I have the original wires off my 67, they are dated 1 qtr 66 and they are exactly as Bill explains.

These wires are not carbon, they are solid core. Is that correct, I will post a pic when batteries charge.

[William C.]

Re: Spark plug boots

Actually if they are original wires and you are looking into the terminal, you are seeing a staple (copper) that was inserted about 3/4 inch into the graphite impregnated rayon/linen conductive core just before the terminal was applied. The core was the center of the process, followed by an insulating coat, a rayon innerbraid, and then a final protective jacket.

[Timothy B.]

Re: Spark plug boots

Bill,

That,s exactly what I am seeing. A few of these wires have some corrosion at the plug ends, can you recommend something that will clean them without damage so I can test.

[Ken A.]

Re: Spark plug boots

Just buy one of the new Packard sets from CC or Paragon & be done with it. The 508N set is also for a 340 Chrysler and has incorrect lengths on at least 2 wires in addition to the red boots.

[William C.]

Re: Spark plug boots

The distributor ends are made of brass, so any light abrasive or small wire brush on a dremel tool should clean them. The sparkplug end is tin plated steel, so corrosion there is a little more problimatic! First thing if they are originals is check the resistance. Should be around 5-6 thousand ohms per foot max! Not many used ones will get there. They were not designed for a 40 year lifespan!

[Timothy B.]

Re: Spark plug boots

Bill,

The corrosion is at the spark plug ends. I was thinking about muratic acid cut 50% to clean rust. Some look like the tin plating is rusted away but they all look solid at the spark ends, the distributor ends look fine.

I replaced them with NAPA wires in 1987 and removed and labeled the wires with the plug they came from. I want to check exact length for each one and record for myself. The boots are not torn either..

[William C.]

Re: Spark plug boots

I'd probably stick with brass brushes to deal with the corrosion, the conductor is a graghite impregnated rayon cord with a linen strength member. I'd also check the resistance of each wire before I did anything.

[Timothy B.]

Re: Spark plug boots

Bill,

I will check each wire and compare resistance to your above post before I go further. Thanks for the suggestions..