Lotus Elan

Off to get car tuned UPDATE.....

PostPost by: PeterG » Tue Aug 30, 2016 6:25 am

Well setting off this morning to get the car tuned, bit spluttery low down and does smell of petrol when you follow it, so I'm told. The carbs will wan't setting/balancing so off to a guy who's been recommended as one of the best.
Should get it back Wednesday.
Last edited by PeterG on Thu Sep 01, 2016 6:18 am, edited 1 time in total.
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PostPost by: Dr Mike » Tue Aug 30, 2016 6:44 pm

Let's hope you find the right road when you go to collect it!
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PostPost by: PeterG » Wed Aug 31, 2016 8:06 pm

Dr Mike wrote:Let's hope you find the right road when you go to collect it!


It helps when you get the right postcode given in the first place!!
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PostPost by: PeterG » Thu Sep 01, 2016 6:01 am

Well picked the Lotus up this afternoon and it idles a load better and starts straight away.
There were loads of things wrong with it when he first checked it over.

The fuel pump was a Chinese copy, seeing that it was in Japan for years that was not a suprise! Anyway it was pushing out 7.5 psi instead of 3.5 psi so he's rectified that by fitting a new fuel pressure regulator.

Was extremely rich mainly rear carb.
Hydrocarbons were 9500!
Reset to 600.
One of the plug leads were breaking down, he fixed it but I'm going to replace them all with 8mm Magnecore items.
Number 4 plug was breaking down so going to get a set of iridium BPR7EIX ones.
It was running Ngk BP6ES should be Ngk BP7ES.
Carbs; The car was running far too rich.

Venturi was 33 measured.
Main jets were 115 which were wrong so changed to 120.
Air jets were170 which were wrong so changed to 155.
Emulsion F11.
Idle jets 45 F9 which were wrong so changed to 45 F13.
Pump stroke was 16mm which was wrong so removed rods and shortened them to 10mm.
Pump bleed 40.
Float valve 175.

The idle mixture could not be corrected using these or correct spec 50 F8 idle jets.
Substantially weaker 45 F13 were required in order to rectify idling and light throttle mixtures.
Parts neded were four main jets, four air jets, four idle jets and a new fuel pressure regulator.

Summing up,car runs great now little bit of flutter at 2500 revs but revs all the way now and no smell of petrol.
Worst thing was bonnet opening on the A19 at 80 mph. Stopped and it was the bonnet hinge on the rhs was loose so just took the bonnet off and put it in my other car I came over with.

Enjoyed the ride home and love the way it drives now.!
Going to sort the bonnet out tomorrow weather permitting, may have to search on what to do though.
Oh found it it's got a Lumenition Magnetronic integral electronic ignition conversion to.

The guy who set it up is called Ron Harper he races old cars. he's got a 26R chassis running a Honda V Tec engine.
Big thanks to him for all he did, great, old school chap,very knowledgable and good crack.
Regards Pete.
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PostPost by: rgh0 » Thu Sep 01, 2016 10:36 am

PeterG wrote:.....Number 4 plug was breaking down so going to get a set of iridium BPR7EIX ones.
It was running Ngk BP6ES should be Ngk BP7ES.......
Pete.


It sounds like the carbs and fuel pressure issues causing rich running have been reasonably well sorted now but perhaps its going lean still on the transition to the main jets at 2500 rpm if it still if not perfect their?

For plugs I would stick with BP6ES the BP7ES are to cold for normal road use despite this being the equivalent of the Lotus original specification, I think Lotus drove the cars harder than you can these days except on the track or the German autobahns. I also would not waste money on iridium plugs. They are designed for long life in emission controlled fuel injected cars. In Carb Elans they will die just as quick as conventional BP6ES due to insulator fouling. Just replace your plugs once a year now that your engine tune is OK and you should have no problems.

cheers
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PostPost by: PeterG » Thu Sep 01, 2016 11:01 am

Which air filter is best as I'd like to replace it shortly.
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PostPost by: Dr Mike » Thu Sep 01, 2016 11:04 am

For those who are new to Weber DCOEs, here's a link to Dave Andrew's simple but excellent guide to tuning them, including a guide to selection of jets etc.
http://www.s262612653.websitehome.co.uk ... webers.htm
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PostPost by: Craven » Thu Sep 01, 2016 1:07 pm

Those serious about tuning Weber carburettors will not do better than buy the genuine Weber publications covering the DCOE range.
Plenty think they know more than the manufacture but they are simply wrong.
Remember Lotus used off the shelf carb?s not one specifically designed for their engine.
Ron.
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PostPost by: Dr Mike » Thu Sep 01, 2016 3:16 pm

Oh how patronising. This forum is for helpful comments.
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