Lotus Elan and Lotus Elan Plus 2 Forums

I think it's time to seek expert help, I've got a low throttle misfire and have run out of ideas. Replaced everything on the ignition side and have eliminated a high speed RFI issue, now think it must be carburation.
Can anyone recommend someone who knows their way around a Twincam with Dellorto's local to me in South Bucks, UK, who can do a diagnosis?
Thanks.

I have Heard good things about these people. Based near Winchester
https://www.aireytuning.com/

Thanks, I spoke briefly to a guy at Kop Hillclimb on Sunday and he recommended a garage in Maidenhead (I think) who'd worked wonders on his Elan. He said he visits this forum frequently so maybe he'll spot this and remind me of their name!

chrisbeck wrote: he recommended a garage in Maidenhead (I think) who'd worked wonders on his Elan.

Maybe Steve Williams Sportscars?

http://swlotus.com

Max Hurst. Max 500 in Guildford.

Chris
That might have been me.
I used a local classic car specialist in Oxfordshire.
https://classic-car-services-oxford.co.uk/
Toni sorted out my Sprint running badly when I was struggling. (Newish Lumenition faulty which caused some other electrical issues).
He does not have a rolling road but worth a call.
Clive

chrisbeck wrote:I think it's time to seek expert help, I've got a low throttle misfire and have run out of ideas. Replaced everything on the ignition side and have eliminated a high speed RFI issue, now think it must be carburation.
Can anyone recommend someone who knows their way around a Twincam with Dellorto's local to me in South Bucks, UK, who can do a diagnosis?
Thanks.

if you are unsure about the carburetion somehow (I understand you've cleared out possible ignition issues, and would have made sure carbs are clean and nominally jetted - but also and more importantly if everything else is stock the fuel level in the bowls), a measure of richness may be a quick way to assess that more accurately than by the look of spark color via the use of a wideband lambda sensor. The best is to have a bung welded to the exhaust, but one can also get a measure at the exhaust, though less accurate (esp. a low revs)

cliveyboy wrote:Chris
That might have been me.
I used a local classic car specialist in Oxfordshire.
https://classic-car-services-oxford.co.uk/
Toni sorted out my Sprint running badly when I was struggling. (Newish Lumenition faulty which caused some other electrical issues).
He does not have a rolling road but worth a call.
Clive

Hi Clive

Great to chat to you at Kop Hill on Sunday. I went there expecting to spend most of my time amongst the two wheelers but the Lotus owners were much more interesting!

Despite being just up the road from me I hadn't come across Classic Car Services before. That's another one to add to my list of small local specialists to turn to when things go pear shaped.

Stuart

Novatech in Slough
Novatech.info
he worked on my Weber's and removed a Low rev stumble, I have seen him tuning a 2 seater Elan also.

Knows what he is doing.

nmauduit wrote:

chrisbeck wrote:I think it's time to seek expert help, I've got a low throttle misfire and have run out of ideas. Replaced everything on the ignition side and have eliminated a high speed RFI issue, now think it must be carburation.
Can anyone recommend someone who knows their way around a Twincam with Dellorto's local to me in South Bucks, UK, who can do a diagnosis?
Thanks.

if you are unsure about the carburetion somehow (I understand you've cleared out possible ignition issues, and would have made sure carbs are clean and nominally jetted - but also and more importantly if everything else is stock the fuel level in the bowls), a measure of richness may be a quick way to assess that more accurately than by the look of spark color via the use of a wideband lambda sensor. The best is to have a bung welded to the exhaust, but one can also get a measure at the exhaust, though less accurate (esp. a low revs)

I wonder if I've disturbed some debris when I removed the carbs, either that or should have fitted new O-Rings on the manifold plates and I'm sucking in air? How difficult is it to check the jets are clear? Can I do it with the carbs in situ?

Hi Chris,
An easy test for air leaks inwards at the carburettor plates is to spray a little carb cleaner or similar volatile fuel there. Propane will probably work equally well.
If there is a leak then the engine will respond to it.
Eric in Burnley
1967 S3SE DHC

Good idea, thanks!
I'm reminded of listening to a colleague's +2 and being able to hear the carb sucking air because he'd trapped an O-Ring, it was too high a frequency for him to hear. Next time I saw him he had hearing aids!