Petrol Smell

[Bahtatboy]

My 40 DCOEs are as shown -- in absence of a filter box, should the holes just above the left-hand trumpets be covered or plugged? I suspect they're the source of the strong petrol smell...

[Billmack]

They need to be open. If you get an air filter it will be cut to leave them open. Without a filter or ideally an airbox webers are somewhat smelly. There is a fair amount of spitback going on. That being said do make sure there are no obvious leaks there. The sparky starter is right below(and for that matter so is the sparky distributor.

[Bahtatboy]

They need to be open. If you get an air filter it will be cut to leave them open. Without a filter or ideally an airbox webers are somewhat smelly. There is a fair amount of spitback going on. That being said do make sure there are no obvious leaks there. The sparky starter is right below(and for that matter so is the sparky distributor.

Thanks

[Andy8421]

Bill is correct, those holes are the air feed to the jets and pressure equalisation to the float chambers. They need to be connected to the same source of air as the trumpets (to match pressure) - usually via a hole in the airbox.

The video linked to below shows a Lotus backplate where you can make out the holes. It also shows at 0:49 'standoff' where fuel is blown out of the carb intakes. IMO Mr Chapman's original design of air intake is best.

https://www.youtube.com/watch?v=84wJ4AodO-8

[elans3]

As you don't have original to Elan carbs (you have 40DCOE 151's fitted), It would help if you could tell us what jets are in them, (to see if you have the correct ones), then we can go from there. If they're not right, then that could be a source of the problem, along with float heights, gaskets, etc.
Firstly can you determine whether they're leaking, and if so, front or rear of the carb ? There's an issue with some 40DCOE 151's which results in vacuum pulling neat fuel through the system and out of the back via the choke lever housing, petrol then drips down the back of the carb body and, if it's the front carb, it drips all over the distributor.....
Next time you go for a run, when you come back, leave the engine idling, and feel around the bottom rear of each carb, to see if there's any petrol dripping, or if it's wet with fuel. If so, you likely have this issue.

[Bahtatboy]

As you don't have original to Elan carbs (you have 40DCOE 151's fitted), It would help if you could tell us what jets are in them, (to see if you have the correct ones), then we can go from there. If they're not right, then that could be a source of the problem, along with float heights, gaskets, etc.
Firstly can you determine whether they're leaking, and if so, front or rear of the carb ? There's an issue with some 40DCOE 151's which results in vacuum pulling neat fuel through the system and out of the back via the choke lever housing, petrol then drips down the back of the carb body and, if it's the front carb, it drips all over the distributor.....
Next time you go for a run, when you come back, leave the engine idling, and feel around the bottom rear of each carb, to see if there's any petrol dripping, or if it's wet with fuel. If so, you likely have this issue.

Thanks, will do and report back!

[gherlt]

Has it an electrical fuel pump ? If so, how many psi does it deliver ?

[Hawksfield]

Bahtatboy

That's a great engine bay makes me jealous mine was like that in 1987
If the smell is in the garage it could be the fuel tank breathers.

Do you run it as shown in photo. I would worry about running without an airbox with Weber's they certainly need one to minimise fire.

[Bahtatboy]

Bahtatboy

That's a great engine bay makes me jealous mine was like that in 1987
If the smell is in the garage it could be the fuel tank breathers.

Do you run it as shown in photo. I would worry about running without an airbox with Weber's they certainly need one to minimise fire.

Is there anything I can do about the breathers? However, I also get the smell when it's in motion...

Would this box / filter arrangement cut down the smell from the carbs?

[Andy8421]

Would this box / filter arrangement cut down the smell from the carbs?

Assuming that is the source of your problem, I am afraid not. It is possible that the filters will become fuel soaked, and smell more, that is if they don't catch fire.

You have a very nice looking engine bay there, and I guess a very nice engine. Driving for a few hours on a summer's day on a dusty road will knock 1000s of miles off the life of the engine without filters - and probably clog up the smaller jets in the carbs. The gauze over your trumpets will stop birds flying in, but won't do much else I am afraid.

The original airbox / remote filter is a good arrangement. It draws cool air from a relatively high pressure zone in front of the radiator, and the airbox contains the fuel 'standoff' which I linked to earlier. If your concern is performance, I race(d) an Elan and the cars that won used a standard remote filter arrangement (albeit with a deeper airbox).

The plus2 is well known for petrol smells from the tank filler / breather arrangement, which probably could have done with a bit more development before the car was launched. Carbs can smell, but were it me (given the plus2 has form in this respect), I would investigate the tank / filler / breather first... and I would fit an airbox / filter.

[Bahtatboy]

Would this box / filter arrangement cut down the smell from the carbs?

Assuming that is the source of your problem, I am afraid not. It is possible that the filters will become fuel soaked, and smell more, that is if they don't catch fire.

You have a very nice looking engine bay there, and I guess a very nice engine. Driving for a few hours on a summer's day on a dusty road will knock 1000s of miles off the life of the engine without filters - and probably clog up the smaller jets in the carbs. The gauze over your trumpets will stop birds flying in, but won't do much else I am afraid.

The original airbox / remote filter is a good arrangement. It draws cool air from a relatively high pressure zone in front of the radiator, and the airbox contains the fuel 'standoff' which I linked to earlier. If your concern is performance, I race(d) an Elan and the cars that won used a standard remote filter arrangement (albeit with a deeper airbox).

The plus2 is well known for petrol smells from the tank filler / breather arrangement, which probably could have done with a bit more development before the car was launched. Carbs can smell, but were it me (given the plus2 has form in this respect), I would investigate the tank / filler / breather first... and I would fit an airbox / filter.

Thanks for your thoughful answer. Right, off to hunt down a standard remote filter arrangement. Anyone got one for sale?

[elans3]

Agree with the post above. Original Airbox / backplate & filter arrangement is best in an Elan. They're never cheap when offered for sale, but are without doubt the best solution. I'd get the backplate, airbox & air hose asap, then, whilst waiting for a filter housing to come up, you could use a suitably sized cone filter for the interim.
They all come up from time to time.

[Bahtatboy]

Agree with the post above. Original Airbox / backplate & filter arrangement is best in an Elan. They're never cheap when offered for sale, but are without doubt the best solution. I'd get the backplate, airbox & air hose asap, then, whilst waiting for a filter housing to come up, you could use a suitably sized cone filter for the interim.
They all come up from time to time.

Thanks.
Jeez -- how is £240 for a steel back plate justified?!

[richardcox_lotus]

Agree with the post above. Original Airbox / backplate & filter arrangement is best in an Elan. They're never cheap when offered for sale, but are without doubt the best solution. I'd get the backplate, airbox & air hose asap, then, whilst waiting for a filter housing to come up, you could use a suitably sized cone filter for the interim.
They all come up from time to time.

Thanks.
Jeez -- how is £240 for a steel back plate justified?!

Supply and demand. Welcome to Lotus pricing !

Your car does look lovely, by the way.

Regards
Richard

[Bahtatboy]

Agree with the post above. Original Airbox / backplate & filter arrangement is best in an Elan. They're never cheap when offered for sale, but are without doubt the best solution. I'd get the backplate, airbox & air hose asap, then, whilst waiting for a filter housing to come up, you could use a suitably sized cone filter for the interim.
They all come up from time to time.

Thanks.
Jeez -- how is £240 for a steel back plate justified?!

Supply and demand. Welcome to Lotus pricing !

Your car does look lovely, by the way.

Regards
Richard

Damned economic theory!

Thanks, been waiting a while to find one in this condition and to this spec -- and even though (or because?) she's undergone extensive refurbishment, I was expecting teething trouble. C'est la vie...