Vent system rollover valve

[Lotusfab 3,174]

Apparently, the S1 vent pipes do not cross over but run through a rollover/vent valve and the vent pipe goes straight down and out through a hole in the wheel arch. Can anyone confirm this and recommend a rollover valve am thinking of using an inline modern valve.

[Lotusfab 3,174]

Has anyone tried using this valve as found on Ebay, looks like good for job?

[molemot 521]

Logically, as long as it allows air into the tank and stops fuel flowing through if you end up upside down in a ditch, it ought to do. I hav no knowledge specific to the S1 fuel system, however.

[Lotusfab 3,174]

After a bit of research have decided this valve is not a rollover valve as described. The alternative cost twice a much but has a ball bearing inside. This valve is misdescribed and is not suitable for tanks venting. The vent must allow two way tank ventilation to prevent pressure build up in hot conditions or fuel vacuume, unless the car inverts at which point the line must be closed off. This is only possible with a ball bearing valve. On the incline the bearing moves under gravity and blocks the vent line. There are several on ebay that are suitable, but not the one I listed.

[marcbria 18]

Mind posting which one you ended up using?

[Lotusfab 3,174]

This is the valve I have decided to use. It's not ideal as it's supposed to be tank mounted, but it's reasonable value compared to the rest and available on ebay. Plan to adapt it as required and use as an inline valve from the filler pipe which will vent throughout each wheel arch.

[marcbria 18]

When you say through the wheel arch, is there a separate hole or are you just going to run it down to the drain hole under the fuel tank?

[Lotusfab 3,174]

There are already holes in each wheel arch where the vent pipes go. Am trying to get some original Esprit rollover valves, but if I can't I already have the ones above. Plan is to machine off the centre nut into a circle of a suitable pipe diameter. The pipe will push onto the new circle making a seal with the open vent in the pipe. With then connect the original vent pipe either side using adapters.

[Lotusfab 3,174]

Well have been given incorrect info on this. Apparently UK cars didn't have the rollover valve, just federal cars. If short pipes are used more chance of fumes. With the parts manual vent pipe type installation a rollover valve is not required because the vent pipe outlet is lower than the tank ( higher if the car inverts). Should have thought of this myself, never mind Collin Chapman did already! Ps pipe exit is single pipe just infront of rear wheel. The wheel arch hole is for the boot board I think?

[marcbria 18]

That makes sense, the federal version had a charcoal cannister and fume recovery system which the domestic version did not have. I've been trying to find a suitable breather solution for my car as it was originally a federal car but the cannister and vent lines were removed and caped and the fuel caps were ported with small holes and no role over protection.

Now that I look a the parts manual for the fuel system there is this

 

 

Non-Return Valve A076L6001F * * 2       In Filler Breather Pipe

 

Which is marked as for all cars and there are two. So there may be a valve on the domestic version too.

[Lotusfab 3,174]

The latest info I have makes sense. The long doubling of the pipe makes it less likely fumes with be a problem. If the car inverted the breather exiting just in front of the rear wheel arch would be above the fuel tank and so the fuel could not run out unless the breather was ruptured. Unlikely event. The valves above would still work and might be a better solution, but I think longer breather lines should be used to help prevent fumes. Think I'm going down the valveless route( have the valves already, so will revert to plan A if not satisfied.

That makes sense, the federal version had a charcoal cannister and fume recovery system which the domestic version did not have. I've been trying to find a suitable breather solution for my car as it was originally a federal car but the cannister and vent lines were removed and caped and the fuel caps were ported with small holes and no role over protection.

Now that I look a the parts manual for the fuel system there is this

 

 

Non-Return Valve

A076L6001F

*

*

2

 

 

 

In Filler Breather Pipe

 

Which is marked as for all cars and there are two. So there may be a valve on the domestic version too.

[marcbria 18]

Please post photo's as I may copy your setup.

[Lotusfab 3,174]

Will post no problem, might take a week or two to get it sorted.

[Lotusfab 3,174]

Brian, have posted some pics on my restoration blog, pt2 the continuation, have adopted this solution after getting some expert advice hope it's of use.