Lotus Elan and Lotus Elan Plus 2 Forums

I took my car to the rolling road, at Mikeanics, Congleton, Cheshire.Mature guy, very experienced.

He set it up, and told me the fuel levels were high, so adjusted them.

It measures 46mm rim to fuel.

16mm float gap.

Running better than it has in years, and no sooting up of plugs.

I'm not changing anything!!

PS

Sorry for starting this prolonged saga off!

alfadave wrote:I took my car to the rolling road, at Mikeanics, Congleton, Cheshire.Mature guy, very experienced.

He set it up, and told me the fuel levels were high, so adjusted them.

It measures 46mm rim to fuel.

16mm float gap.

Running better than it has in years, and no sooting up of plugs.

I'm not changing anything!!

There's a very good lesson to be learned there - i.e don't waste time and money trying to do the jetting and choke sizes yourself. There's endless numbers of posts on this forum of people trying to do just that. Doing it yourself is like trying to grind the journals on your crankshaft by using a hand file!

marode wrote:What type of ignition/distributor do you have? I have the original 23D4 distributor, have cleaned and oiled all moving parts. Ignition is by Powerspark. 14 degree max advance is stated in the manual and this is exact what I get with setting static (and idle) ignition set to 12* (12+14=26).

But I´d like to keep the topic more on fluel levels and float bending. So, has anyone here ever gained any significant improvements with altering the fuel level while setting up caburettors or is this only theory?

I'm using 123.nl distributor - the fuel level is one of the parameters that sets the richness along the RPM curve, if you have it correct (says with your 12-14 AFR tune) then altering the fuel level is not goig to give you extra power more than fine tuning richness by other means (getting a bit leaner if your too rich) - but for a given richness timing would make some difference (not huge, but more perceptible than fine tuning richness I would bet). If you want to keep your original dizzy you may (at your own risk, standard disclaimer apply...) enlarge a bit the advance opening in the plate so that you get more than 12+14=26. You may also cheat a bit starting at 14 static.
Good luck !

2cams70 wrote:There's a very good lesson to be learned there - i.e don't waste time and money trying to do the jetting and choke sizes yourself. There's endless numbers of posts on this forum of people trying to do just that. Doing it yourself is like trying to grind the journals on your crankshaft by using a hand file!

maybe for you, but I'd rather any day spend time and money to learn even if just a bit rather staying in the dark.

as for crank grinding with a hand file the comparison is moot since jetting is fully reversible (not mentionning that I've never heard of anyone "grinding" a crank with a file)

It takes all kinds I suppose, but deterring people from maintaining or tuning their car is not how I see keeping the Lotus spirit alive.

alfadave wrote:It measures 46mm rim to fuel.

By "rim" you mean top round edge of the carb cover (where the jet cover seals)? Or that bridge slightly underneath?
I use a caliper with depth ruler and place the caliber with its bottom on the round edge. With that I now have 44-45mm, but floats are now set to 10.5mm distance to cover.

nmauduit wrote:maybe for you, but I'd rather any day spend time and money to learn even if just a bit rather staying in the dark.

as for crank grinding with a hand file the comparison is moot since jetting is fully reversible (not mentionning that I've never heard of anyone "grinding" a crank with a file)

It takes all kinds I suppose, but deterring people from maintaining or tuning their car is not how I see keeping the Lotus spirit alive.

If I was wealthy enough to own my own chassis dynamometer or could access one for free and was also wealthy enough to have on hand a full collection of jets and chokes to experiment with I might be tempted to play around myself too.

Most mere mortals however aren't in that position and it just isn't cost or time effective. Plus getting it wrong can damage an engine

Marode.
Yes, the top round edge.

Learning by doing is one of the most effective forms of education.
Until you are sure you have a stable fuel level, maybe a good pressure regulator set at 2.5 psi, all efforts to fine tune will elude you. Remember a carburettor is and imperfect instrument.

Craven wrote:Learning by doing is one of the most effective forms of education.
Until you are sure you have a stable fuel level, maybe a good pressure regulator set at 2.5 psi, all efforts to fine tune will elude you. Remember a carburettor is and imperfect instrument.

Yes it completely amazes me that people will happily play around with jet sizes and chokes and other critical calibrations without first having properly made sure that the carburettors are in prime rebuilt condition and clean.

It also completely amazes me that people will farm out rebuilding carburettors to specialists or dismiss the original carburettors in favour of new replacements. Carburettor rebuilding is somehow regarded as a mysterious "black art" (it's not) whilst messing around with critical jets and other calibrated components is regarded as being well within the scope of DIY for the inexperienced and without a dynamometer!!

I really don't understand you blokes sometimes............

2cams - "Most mere mortals however aren't in that position and it just isn't cost or time effective. Plus getting it wrong can damage an engine"


Yes, but it is immensely satisfying when one does get it right!! D

TBG wrote:Yes, but it is immensely satisfying when one does get it right!! D

It's only right when it's proven on a dynamometer!

2 Cams "It's only right when it's proven on a dynamometer!"

Well you are fully entitled to your opinion, but after over 200k miles I think I know when the car is feeling right! Off to the Italian lakes at the end of June, a round trip of about 2.5k miles so we will see!! D

2cams70 wrote:It's only right when it's proven on a dynamometer!

I don't really agree with that. For a road car your tuning the car to get the "right" air fuel mixture and good driveability not every last bhp.

With the availability of reasonably cheap ($150usd) afr gauges it quite possible for a owner with good understanding to get to a decent state of tune. It may not be perfect or as good as a rolling road run by an expert but good enough for the use.

Given that a change in temperature, altitude or move between summer and winter fuels can have noticable effect on the state of tune. As soon as you leave the rolling road the tune will move away from perfect.

Personally I do it myself as there is a lack of experts and rolling roads where I live. So better to invest in a selection of jets and do it myself. Which also allows me to change it later for different conditions, e.g if I go to Colorado where is much higher.

"Personally I do it myself as there is a lack of experts and rolling roads where I live. So better to invest in a selection of jets and do it myself. Which also allows me to change it later for different conditions"

Hurrah to that!! D