Thread: Waterproof your V8's Ignition

Found this on another website, found it pretty useful so thought I'd share.

How to make the Rover V8 resistant to ignition failure in water.
First of all you need to decide just how water proof your engine needs to be, I will briefly outline three options here;

1.) Splash proof - this is all you need for most off roaders that dont have snorkles.

2.) Short term wading - For off road racing where you are getting water forced into the engine bay.

3.) long term wading - For seriouse off roaders with full snorkle that will drive with water line above top of engine.
Water causes the high tension side of the ignition to arc to ground only if it has a path right to the conducting parts of the system. Similarly it can effect the low tension side too. All we need to do is stop it getting to those parts.

First of all, it is vital to have the basic parts of the system in good order before we start modifiying anything else. Good quality 8mm silicone leads should be fine (even 30000 volt systems wont arc through that much silicone!). You dont need any special purpose leads just good quality standard ones. Make sure the boots at each end are either bonded on or very tightly fitting, you could bond them in place with silicone but its better to start with decent leads in the first place. With new spark plugs the new leads should fit with a water tight seal anyway. Old leads go hard and will leak here. The same goes for the dizzy cap end. The dizzy cap should again be a good quality standard item, check it fits the dizzy casing well and that the centre electrode spring works properly.
With all the low tension connectors, I always spray them with contact grease to prevent corrosion. The coil driver (SD1 or Land Rover types) will work quite happily under water as the electronics is sealed anyway but a coating of spray grease will help prevent problems if there are any small cracks in the resin.
With the basics sorted, your next problem is the dizzy itself. In particular the two breather holes in the casing just below the advance weights. These holes are very important, they prevent a build of of crank case gasses (which leak up the dizzy shaft) which could otherwise blow the dizzy appart. Here the three options come in.

1.) Splash proof.
If you are mostly green laining and have problems with the engine spluttering every time you go fording, the chances are that a small ammount of moisture is getting through the breathers and causing a bit of arcing in the dizzy cap. In most cases a simple splash gurd will direct the water away from this area and all will be well. In some vehicles water will be thrown up by the crank pully so a small shield is needed here. The shield only needs to be a thin piece of plastic held on to the dizzy with a tie wrap or similar, as long as it is secure. Remember to put some silicone grease round the base of the dizzy cap to help the seal.

2.) Short term wading.
This is when you are driving through small rivvers quickley (shuch as in a Comp Safari race) wher there is water everywhere in the engine bay but it is not actually submerged. Good splash guard should still work for most applications but if not then now the breathers need to be dealt with. Take the dizzy out of the engine and drill the holes out and tap them for 2BA breather nipples, make sure you trim the thread of the nipples down to 1.6 mm else you risk them fouling the advance weights, always check on your dizzy how much clearance you have. Then drill an tap for another nipple just down stream of the throttle (this will draw gas out of the dizzy) and one between the throttle and air filter (this will let clean air in to the dizzy), see pictures below. I got the nipples and some silicone tubing from a model shop, apparently they use it for fuel on model aeroplanes, costs a couple of pounds. Reassemble the dizzy into the engine (check alignment and not just timing) and you should be able to throw a bucket of water at the engine without it missing a beat.

3.) Long term wading.
If the water line is above the top of the engine then you have the additional problem of condensation and water seeping under pressure through every joint in the system. Proceed as in the above example but you will also need to bond in and seal the electrical connection on the dizzy and also the joint between the vacuum advance unit and the dizzy body. Some vacuum advance units have a breather hole which will have to be connected to fresh air via a pipe as well. If you are doing this sort of work then you will by now have many breather pipes (rocker covers, axle etc) but dont be tempted to connect this to one of the other breather pipes as a small pressure change will effect timing. The dizzy cap will have to be bonded to the base with silicone sealent which will have to be replaced every time you take the cap off.
So there you have it, there are more advanced ways and there are definately more expencive ways but this is all you realy need to sort out the ignition on that splendid V8.

.Breathers arrowed.

Originally Posted by superquag

I read somewhere that these had been trialled..and were an overall 'Fail', mainly due to retaining water and humidity. - Water if the sealing was'nt 101%, and humidity - long term - after water exposure or just general atmospheric moisture.

The most elaborate system I've seen was a small air-pump that gently pressurised the distributor with filtered air drawn from the cabin. A bleed-out hole kept the air 'changed'.

Logically, you could enclose and pressurise the coil too...

Easier to use a car and submarine for their desighed enviroments...

Hi this is what my friend and I did to our hunting vehicle, we run an air tank any way so he rigged up a toggle switch we flick in the cabin and it pressurises the dizzy, now it can go fully submerged and it doesn't stall out lol, I was a bit unsure when my mate suggested it but it works a treat