Waterproofing Junior

I decided to see how waterproof I could make my petrol engine after seeing lots of Suzuki drivers wading at Tong off road site and other similar venues.

Lets face it it looks like fun. Well until it all goes horribly wrong. Thanks for the pictures Dave.

So how to go about it?

I wrote a list of all the bits of junior that would not appreciate getting wet. 

  1. Electric's
  2. air intake
  3. Oil filler and dipstick
  4. Axel and gear box breathers
  5. Batteries, alternator, started motor

My god there's a lot to consider.


I have started by encasing the coil in a plastic container. this is sealed so no water can get in. The HT lead and wires come out separate holes and are sheathed in shrink tubing. this will prevent leaks and protect the HT system. I have also encased the HT leads in shrink tubing to waterproof them. The spark plugs are shrouded by plastic covers and sealed into the block with a flexible silicone sealant.


The distributor is located high up on the engine on the drivers side. This needs some protection from water being thrown up from the ground as well as the engine bay being flooded.

The dizzy is the difficult bit.

By sealing the Ht leads to the cap water is kept off the connections but the cap its self is difficult to seal down. A cover which is stretchy and will cover both  the bottom half of the cap and the condenser would prevent some ingress but not all. It occurred to me that he distributor  will not let water in if its under pressure so I acquired a compressor. This is intended to power an air horn but with a little adoption it will pressurize my distributor when we go into the water. Keeping water out and dry the thing out is any gets in. It also gives me another something to waterproof.


Using a small 12V compressor and some appropriate fittings I have arranged the air supply. I acquired a new distributor cap form Buckley's Land Rover and Steve kindly drilled and tapped this to take an appropriate air line fitting. .
Here it is all fitted. The compressor will switch on when the isolator switch for the electric fan is switched. A change over relay isolates the fan power supply to stop is throwing water all over the engine bay and switches the power supply to the compressor on. 

The compressor is watertight and and its air intake will come from inside the cab.

Electric Fan

The fixed fan on the front of the engine is the cause of allot of the electrical problems experienced by petrol engines when going through water. By replacing it with an electrically powered fan the amount of water that gets onto the engine and electrical systems can be dramatically reduced.

Junior already had an electric fan installed when I bought him so I have made this the main cooling fan. The full story and wiring diagram is on Juniors Electric Fan page.

Air intake

I got a remote air filet box from the last land rover show I went to. All that's missing is an adaptor for the SU carb we fitted last month. This is going to be another bespoke creation. After that its just a case of connecting the pipes and sealing the whole system with silicone. Its all going to fit on the passenger side in an attempt to give me some more visibility but there's not allot of room so its all going to be a snug fit.

The air intake on junior uses a K&N filter and sounds great. In order to make sure it doesn't get any water in there I will need a snorkel. This consists of a tube up the outside of the windscreen through which air will be drawn. I acquired the parts to install this on beast but never got round to it so they have now been passed down to junior. 

The snorkel is going to be fitted on the passenger side since there's not much visibility in a junior with the roll cage tubes running up the sides of the windscreen. another tube on the drivers side would be suicidal.

I have cut a hole in the wing top and in the checker plate protector. this took hours to get right. Mostly because I needed a few beers before going ahead and taking a jig saw to the wing again.

Fitting the air filter in was a problem This engine and engine bay was not designed to have a couple of large air pipes and an air filter box installed on the passenger side. 

This is how it looked before I started work

5 minutes later I have decided that the heater is not as important as the engine and started dismantling the system. It turns out the fan didn't work after I dropped it onto he pavement so its all for the best.
10 minutes later. All cleared out of the way. I now have room for the snorkel to come through the wing, the air filter to be secured and for all the pipes needed. Only  Problem now is I have no heater.  

Oil filler and dipstick

The oil filler is situated on the front of the engine with a breather on the rocker cover.

This breather I intend to route to its own dedicated pipe into the air intake system this may need a one way valve on it. the filler on the front is a more difficult problem. while it still needs to act as a breather it will be vulnerable to water if the water is deep enough to come into the engine bay.

I am looking for a method of sealing the top and connecting it to the breather system. Anyone any thought send me an email to Enquiries@Negativeart.com

Axel and gear box breathers

These were a simple problem to fix. The Land Rover axel has a tapped hole in the top surface. This usually has a ball valve screwed in to it but I have never trusted these. I acquired from my local air power center some fittings an made up a system of pipes and connections eventually these will lead up the outside of the snorkel but not until its fitted that's a job for the future. These should make a closed system which will not allow water in unless I go in deep enough to get water over the roof. Better not do that then then.

And here's the parts ready to be assembled. The pictures show the route the pipe takes from the axels, joining together near the bulkhead and then extending up the roll cage. I have looped the pipe over to prevent rain or condensation on the cage getting into the pipe. It will also form an airlock if water gets up this far during wading but I will need scuba gear long before this happens..

The gear box does not have the tapped holes like the axels so I had to drill and tap the the plates on the top of the gear box and the transfer case. Then seal the old style breathers with silicone. This should make the transmission much more watertight but it will still find its way in somewhere.

Batteries, alternator, starter motor.

If I get the battery wet I assume it will discharge, but you can't really seal them in as they give off hydrogen. So I have put the batteries under the passenger seat. This set up has been quite successful in beast and and it gives some more room under the bonnet. For more details click the pictures below. 

As for the alternators and starter motor. Well the landy starter is quite a well sealed item so I suspect a guard to deflect some of the muck will suffice. This is not perfect I know but once junior has been in the thick of battle a few times I will be better able to see if more extreme measures are required. 

The alternator has to be driven by a 'V' belt from the front pulley so again I think a guard will be all that is possible. Alternators can develop some considerable heat and so are open to atmosphere to aid cooling. Any cover or casing I install to prevent  the ingress of mud will require some form of additional cooling.

I am thinking of using a timing cover from a car. These are common in the scrap yard and if one can be found that will fit it will at least deflect some of the mud when the going gets tough. It should also reduce the amount of water being throw around by the fan belt.


Well after all the work it to make sure junior can swim it was good to have the chance to try a little wading. This pond was not all that deep, only 3 feet or so but it was enough to necessitate a snorkel and some waterproofing for the electrics.