Water Proof Spark Plugs

[vicboddy]

Many years ago (35 years!) when I first had a Jupiter I used to suffer from water shorting out the plugs from time to time. I found a set of sealed plugs (memory says they were designed for aircraft engines) where the plug itself was within a metal shround which boted together in three sections, with an O ring seal onto the plug lead some 10 cm up in the air, if I remember rightly. And I never had trouble again.

I see no discussion on plugs on Jowett talk. That suggests water is not an issue. So does that mean everybody uses this type of sealed plug -- or that nobody does? And if people do use them, where do they come from and what spec is best? I remember having several different ones with either one, two, or three 'fingers' at the spark end.

regards Vic

[Keith Andrews]

Im not familar with the jupiter dizzy cap..
But the bradford cap and screw in HT lead fiitings fit modern 8mm leads
At the other end a good set of aftermarket good fitting boots.

On both the Bradford and Camaro I run 'Top Gun" stainless steel spiral wound carbon core 8mm leads

Water issues...one hast to understand the nature of the current
the current will naturaly run the route of the least resistance.
In the ht circuit (putting aside the resistance of the lead) has the gap between the rotor and cap pins, and the gap of the plugs.
What is critical is the total gap of both of these.
Hence assesive pin corrosion/deposits can have a huge effect when one is dealing in 1/1000s"

The next thing is the HT leads...good leads will last decades...what kills leads is just that once pulling a plug holding onto a lead rather than the boot..

Even with high voltage coils (which jowetts dont run) ht leads without boots work fine when everything is in good condition...under these circumstances , it more or less takes a bucket of water to kill the spark..
Or plug stems that are dirty..
Personally I NEVER use CRC type products on my electrics...these are short term solns.
What happens is the crc leaves a greasy film, this film collects dust /debis, even a small amount not seen by the eye can cause issues
The best method is do it the old school way, clean and dry by hand.

[PAUL BEAUMONT]

Vic, I know that there are several waterproof plug caps on the market today, especially for Japanese motorcycles, but I am wondering if the answer to your question more lies in the fact that now that our motors have reached a venerable age, no one takes them out in the rain!!

[TedAllen]

Hi Vic'
Being involved in roadside rescue and recovery for the last 30 years I have dealt with many vehicles with tracking high tension. As Keith rightly says, the tracking will take the line of least resistance and jump across the smallest gap it can find. I make sure on the Javelin that the smallest gap in the line of current from the dizzy cap to the plug is actually the one at the end of the spark plug, where it should be.
I do not run with covers on the heads and use straight, good quality caps rather than those cranked to a right angle. This keeps the entry point of the HT cable into the cap well away from the metal of the cylinder head. The current cannot jump this gap and goes where it should go. I do not use modern cables, preferring the old fashioned copper core ones.
I have had no trouble whatsoever with tracking in spite of living in the 'Rainy City'.
I am not a great fan of so called waterproof covers on the disributor having dealt with many 'Mini' types which retained moisture long after the rain had gone. I prefer to shield the dizzy from the water as Jowetts did on the Javelin with a plate on the grille.
I also prefer a dry cloth or some soft paper roll to WD40 type products to dry things out.
Ted

[Keith Andrews]

When I refer to "top Gun" (brand name) ss spiral wound...
These are not your normal off the self 8mm leads...
They are hi performace, solvent and heat resistant, silicone street/strip designed for voltages up in the 50/70000 v
most mdern cars have 8mm and about 30/4000v, like our 'hi performce coils
Std older cars are around the 12/24000 v 6mm leads

The secret is not in the core..copper/carbon etc but in the outterlayers
The advantage of copper is they are more robust to abuse..like pulling hy leads off by yhe lead not the plugs...but then as enthusists we never do that anyway.

The set of top guns in the camaro have been there for 200,000 miles and 1986...and often have actually laid on the hot cast iron manifolds...and still havnt a mark on them, leak, with around 50,000v

A note on dizzy water covers...when the spark jumps in the dizzy, it causes a reaction with the air called ozone, high concentrations of ozone can be conductive, causing spark tracking under the cap.
often, espec on high performace pionts dizzys there is a small hole in the bottom of the dizzy, for enough ventilation to keep these concentration down...so dont seal your dizzy.

Another thing to watch for is the length and size of the lead from coil to dizzy...incorrect can cause burning /electrical corrosion of pionts, in effect the same effect if you have the incorrect capsactor...So if you have a damp day, reasonably new pionts, moved the coil, deposts on the pionts can easly diadoned as moisture... one 'drys' clean out and at the same time move enough of the desposts to fix the immediate problem.
Also what can effect is old wire that inside the strands have corrosion on the surface

This and incorrect capacidance can be seen on pionts wear..if the hammer or anval is wearing/pitted...I can rem which way round it goes, but from memory anvail pitted =cap low and visa versa.

Another thing to watch, is when putting in new pionts, run the carboard box flap thru the pionts 1st...during manufacture they apply a very thin of oil to prevent corrosion, if this is not removed it can burn on the points surface giving poor performance, and even in rare occassions no spark at all.

Older cars due to low voltages are generally far more robust than their more modern counterparts, but are more sensitive over time when coil mounting is changed, abuse of leads, not cleaning points befor install etc
Generally it is a combination of these that causes problems rather than just 1...and usually blamed on other issues.

[TedAllen]

Keith,
Just a little observation....I have fitted hundreds of sets of points under all weather conditions and like you, I have always, without fail, run the end of the box between the point faces for the very same reason, even turning the cardboard so the more absorbent side hits both faces......nobody told me how to do this or recommended it and it's not in the manuals, I don't think. How come, 12000 miles apart, we both do the same thing ? Is it just natural cunning ?
Regards
Ted

[paul byrne]

Hi Vic,
I used modern leads with the right angle ends that nomally go to the distributer as the plug conectors (they look neater). However I do two other things. Firstly, seal the cable to the rubber right angle with a little silicon gasket maker. Secondly, I fit an 'o' ring onto the spark plug, into one of its grooves, so that the cover goes over the ring and -hopefully- forms a water tight seal. Seems to work ok but has not had an extreme test yet here in sunny Tasmania!
Cheers

[Keith Andrews]

How come, 12000 miles apart, we both do the same thing ? Is it just natural cunning ?

Well back when I had my 1st car, a 62 Truimph hearld coupe, I ran into the problem...nothing in manuals etc like u say...but fortunaly a m8s old man was an old school mechanic...
I was about 17 at the time.
I suppose like you most of the stuff I meamt, I have learnt the hard way, and most of all sitting down with these old guys, asking questions, listening
Most of them are all long dead now....thinking about it...all of them!!

[Forumadmin]

I use modern plug on leads which have excellent water seals in themselves and do not require the plug covers originally fitted. However, For Winter Rallies when we forded deep rivers, I used the heads with the metal plates for fitting the original sealed covers (but they are fairly useless with High Voltage coil). Instead I used a two inch grommet and finished off with silicone sealer.

However, once the seal is broken it is best to run without cover so as to evaporate any moisture.

[Mike Allfrey]

Dear Vic, and Others,

When, many years ago, I was a young apprentice tractor mechanic, I was taught to thoroughly wipe the points before installing them, with a rag soaked in lighter fuel. My foreman smoked a pipe, and his lighter would not work on tractor vapourising oil (TVO)!

In the early 1960s I used to run my Jupiter between Bristol and Uttoxeter (Staffs) many times a year and in all sorts of weather conditions. I never suffered moisture in the ignition problems. My engine had no cover plates on the heads and the plug caps were simple. loose-fitting KLG covers. I remember once, while heading up the Gloucester road, the good old A38, passing through flood water that came level with the top outer corners of the rocker covers. I know this because I got out, got wet feet, to find out how deep the water was further on! The car drove through the water without any problems.

Even now, I scorn cylinder head cover plates and all sorts of plug covers.

KLG used to make a very effective water proof plug and cover assembly. I found a quantity recently at a swap meet, but they don't like modern petrol at all.

I now use electronic ignition with standard issue plug covers and have no problems. I also have intense scorn for blue plug leads with those awful straight connectors that are always bright yellow and show up every oily finger print!

Yes, it important to wipe the new points at installation time.

All the best,

Mike Allfrey, Victoria, Australia.

[AlanBartlett]

Another way of waterproofing the ht leads from the dizzy could be using a but rubber glove to fit around it and the lead connections. Although it doesnt look orginal. Ive known it work on minis and does an excellent job.

[Mike Allfrey]

The surgical glove is a good idea -- that is why the good Lord gave us five fingers -- to water proof Jowett distributor caps!

Back in the good old days, Joe Lucas used to sell a rubber boot for such as Minis. It was tailor made for the DM-2 distributor with leads coming horizontally out of the the cap.

I wonder if Holden Vintage & Classic are reproducing that one?

Best wishes,

Mike Allfrey.

[TedAllen]

Hi All,
Just as a humorous note to the rubber glove comments, I have just returned from the Moto Coupes des Legendes in Dijon. One of my two travelling companions was riding a Honda Pan European.
On the Autoroute passing Rheims he was aware of something white flapping around his nearside glove box. Seconds later a huge scary white hand came out of the box inflated itself to about 2 feet across and let go, disappearing behind him into the air. We were doing about 100 mph at the time and the latex glove obviously felt at danger and had to escape !
Ted

[Forumadmin]

Dilemma! whether to protect one's parts or hold onto the steering wheel.