Managed to sort out one of those things that has been niggling me for many years now, and that was the front body supports.

Back in the day, when I first built the Buggy, with little or no knowledge, I didn`t realize just how important the front body support was, and for those of you who do not know what I am on about, I am talking about the metal brackets screwed into the tops of the front beam and bolted to hold the front of the fiberglass shell in place just in front of the petrol tank.

Without them, I discovered that in the extreme heat, and with a full tank of petrol, that the front of the bodyshell would droop slightly, just enough for the steering joints to bash against the base of the tank. On several occasions I could be seen trying to put a new clearance dent in the base of the tank in order for me to turn the steering wheel, and got irritated that it would only do it on hot sunny days.

My fix, until now, was two stainless legs bolted to the bumper that went upwards to the front of the tank. It was as effective as it was cosmetically awful, and every time I have had the bonnet off, I have clean forgotten all about them.

Not this time though. A quick natter with my mate Bill, and he quickly produced a pair of heavy duty brackets from bits out of the scrap bin.





They fit perfectly, and the front looks so much better now that those awful legs have been removed.

Today saw some work on my fuel tank that just made my blood boil. I have repeatedly said that putting tank sealant in was the worst thing I have ever done, and today it really came round to bite me hard. For those who do not know what I am talking about, then let me explain.

When I purchased my new tank from Flatlands (a good few years back) they advised that because it had been welded that I should use some sealant in there to seal up any small holes that may be as a result of the welding. They sold me an expensive tin of sealant that was supposed to be Ethanol resistant and its application was fairly simple. Mix it up, pour it in the tank, and then roll the tank about in all directions so that every surface was coated. Seemed good at the time, and I fell for this, hook line and sinker.

A few years back I noticed white bits floating in the tank, and it became very apparent that the internal surface had broken down and had now filled my tank with loads of debris, and I have been pulling it out ever since.

Well today, I moved the tank, and heard it go "thud" and it was obvious that there was something inside there moving about. After using a bent piece of wire, I managed to recover a few more large sections of "ethanol resistant" lining, that has the appearance and feel of rubber, but that was not my issue here. If you look down the filler neck, you will see a very large piece of something that should not be there.

When the tank was initially coated and laid to rest (to set) then any excess is going to run to the bottom of the tank where it will set. I had not envisaged that this would then set into a lump nearly half an inch thick that was the entire shape of the internal base of the tank. The ethanol in the fuel had now attacked this causing this large lump to now float about in the tank. It took me hours with a pair of pliers and a hook to break it up and remove it a piece at a time.



Seriously - do not use this material to seal the tank. If you suspect your tank is going to leak, then buy another tank.

The only good thing I can take from todays antics is that I can probably now get another half gallon into my tank judging by the amount of crap that came out.

Dave I wonder if any small pieces of this sealant have periodically got lodged in your fuel line and choked, or at least restricted, the flow causing poor running - or no running ?

The bits could certainly cause the problems you mention, and I try my best not to let it happen.

I change the filters (multiple) fairly frequently, and I never let the tank level get too low either   

With the amount of work you have had on the shell done and the amount of work your doing on the bibs and bob, I would have just thought sod it and bought a new tank Dave 

I`m coming close to that one Steve, but sods law says that the filler would end up being in a slightly different location, so I`ll keep sloshing this one out for now

Strange stuff your fuel resistance sealer, the stuff I used came in a small tin and looked like silver paint it just about coated the sides and bottom in a thin coat swishing it around.

Strange stuff your fuel resistance sealer, the stuff I used came in a small tin and looked like silver paint it just about coated the sides and bottom in a thin coat swishing it around.

Same sort of thing, but mine was a 2 part one with a catalyst

Over the years, I have experimented with many different types of Petrol Tank Breather methods with varying degrees of success. As I am about to plumb the tank back in, I have been racking my brains to try and come up with a yet another solution.

For those unawares of why we need a breather system, its actually very simple to explain. When the fuel is pumped out of your petrol tank, the space that it occupied needs to be replaced with air. If not, then the lack of air can cause a vacuum to form inside the tank, this in turn causes the pump to work overtime because it cannot pull the fuel against the negative pressure caused by the vacuum, and the long and short of it is that you can end up with fuel starvation. The idea then, is to replace that fuel with air, allowing the tank to "Breathe" and this is often done by a small one way valve that will allow air in, but not allow fuel to spill out. In practice, many of our fuel systems are put together with so many leaks that this seldom happens - and its only when you do things properly that this problem may rear its ugly head.

A few years ago, when basking in the summer sunshine, I had the opposite problem in that the intense heat of the sunshine had caused my tank to get so hot that the pressure had built up inside to such a point that when I removed the fuel cap, it flew out of my hand followed by what can only be described as a fuel volcano that went absolutely everywhere. Thank god no one was smoking nearby, else I would have lost the Buggy, but I did lose the paintwork on the bonnet that year as the fuel attacked it. One of the other side effects was that the fuel pressure was now so high, that the fuel shut off valves in the carbs were being forced open, with the petrol now running down the venturi and into the crankcase. Far from ideal.

The problem with the conventional breather system then is that it often relies on one way valves to compensate for vacuum and not pressure, so what is the solution then? An open pipe would solve the problem allowing air to move in both directions, but I have a slight concern that you may find your fuel simply evaporating on a hot sunny day instead. Conventionally, most of the breather pipes are mounted high up towards the rear of the tank, to prevent any fuel from sloshing about under heavy braking, but you have to be careful here too, because you could end up losing some fuel under hard acceleration instead - and if you route that pipe in the wrong place, then you could end up with it running out quite fast through a process called siphonage.

I have experimented with so called "Vented" fuel caps, but whilst they address the vacuum issue brilliantly, I have yet to see one with a 2 way valve to combat pressure build up under temperature. I am aware that some of you even went so far as to drill a small hole in the top of the cap to act as a breather, but all this did was to allow water ingress during our monsoon months.

Looking at the world of Rallycross, they had what appeared to be a very clever two way inline valve that would allow free movement of air in either direction, but the moment that any liquid was detected the valve would simply shut and prevent any fuel from spilling out (should the car become upside down). These have to be mounted vertically to work properly, and whilst they may function perfectly on a car that is shaken about and then stripped down at the end of the day, I found that when fitted to a daily driver on smooth roads, the potential for failure was actually quite great. I had one of these from Demon Tweeks. It wasn`t cheap at around £65, and it failed on me, along with my vented fuel cap on Volcano day as described above. What had happened was that the pipe going into the valve had allowed a small amount of fuel to become stuck in the pipe on the entrance to the valve, which had been subsequently been detected by the valve, which had now shut. Because the fuel had nowhere else to go, it just sat there, and the valve remained firmly shut whilst allowing the pressure to build up very nicely. A bit of a design flaw there methinks?

Off Road Motorcycles use a similar 2 way valve for breathing, and have a very simple method of shutting the fuel off when the bike goes over by having a small ball bearing to block the pipe. Very simple, very effective, and only costs a couple of quid to purchase. They have to be fitted above the fuel cap though, which does put it inside the cabin area, and the downside of this is a very strong smell of fuel vapour on a hot summers day.

The best system I have seen to date, and by far the most simplest, is the one that Peter came up with, and that is to use a windscreen washer jet as the valve. The hole is big enough to allow air in and out, and yet small enough not to allow water or fuel to pass in either direction. If you have a look at the bonnet on Peters Buggy, you will see a 3rd nipple fitted, and that is his fuel vent. I have used this system for the past few years myself, and if you look back at pictures of my bonnet, the twin washer jets mounted in the middle, were actually my fuel vents. They worked really well.

So . . .  If that system was so good, then why am I looking to change it this time around?

Well, you know by now that I like to experiment with different things on my Buggy (both good and bad), but if the truth be told, this time around, I just don`t want to put any unnecessary holes in my sparkly new bonnet - hence back to the drawing board and this is what I came up with.





Yeah, ok, its a bit overkill, but here is my thinking:

I have used two one way valves connected via a T-Piece. The valve on the left will allow air to be drawn in via the pipe that exits under the tank, and this is marginally lower than the T-Piece so that if any escaped fuel should reside in the pipe, then it will be drawn back into the tank under Vacuum conditions.

The valve on the right allows air to escape when the tank is under pressure, and the pipe goes up and over the tank to give it some height, therefore preventing any siphonage and then exits under the floorpan to prevent any bad smells in the cabin.

Because I have used 2 valves in this way, then under ambient pressure, both valves will be in a closed position and that should then eliminate evaporation.

Time will tell   

[My Youtube channel]

I have experimented with so called "Vented" fuel caps, but whilst they address the vacuum issue brilliantly, I have yet to see one with a 2 way valve to combat pressure build up under temperature. I am aware that some of you even went so far as to drill a small hole in the top of the cap to act as a breather, but all this did was to allow water ingress during our monsoon months.

Got to say, the vented cap on mine has worked really well all these years regardless of temperature. Never know an issue whatsoever. 

I know, Vented caps are usually all that is needed   

But wasn`t until my tank got really really really hot that I discovered that 99.9% of the vented caps out there only have one way valves in them. To be fair, with the temperatures we usually have in this country the pressure build up would probably go un-noticed. I`m very wary of it myself after having the cap fly out of my hands as it was released.

[My Youtube channel]

Wow.... of course mine being a two cap system may help?? will show you more at Swanage. (Oh and my tank might be a little more vented around the neck too... will explain that one there too) 

Whilst the rear wheels are off and access is better, I thought I would do a quick job that you guys told me to do a while back and that is to convert the very long monkey metal bolts holding the carb manifolds on, to studs instead.



There . . .   That should keep a few of you happy   

Wow.... of course mine being a two cap system may help?? will show you more at Swanage. (Oh and my tank might be a little more vented around the neck too... will explain that one there too) 

Raspberry suffers badly with over pressure on hot days to the extent that it pushed fuel past the plastic connector on the fuel gauge sender.

Professor Brian Cox explained why anything red gets hotter than anything in other colours also why the sea looks blue but I digress.

My easy solution was to drill 2 small holes in the inner side of the standard Beetle cap and fit 2 1 way valves pointing in each direction.  As the Doon bonnet is an opener you don't really want lots of pipe work that looks like a mad women's knitting.

I'll show you at Swanage.

That's better, MUCH better