Lotus Elan

Help For A Newbie

PostPost by: robb4100 » Mon Jul 19, 2004 10:47 am

Just acquired a 65 elan with a recently rebuilt engine. The idle is
very rough and needs adjustment. Looking at the workshop manual it
looks reasonable straightforward. Only tool needed is a balancing
tool unisyn flow meter?). Is there any reason a person with
reasonable mechanical skillss(former plumber)should not attempt this
adjustment? Are there any particular tricks or concerns?

Secondly, The clearance under the car is about 5" is this too low?

Thanks
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PostPost by: steveww » Mon Jul 19, 2004 12:36 pm

Before balencing the carbs check everything else is up to spec. Points, plugs, timing, valve clearance.

Using a carb balence meter work methodically through the set up and adjust the mixture at the same time. For the mixture it is a good idea to beg, borrow, steal a CO meter.

If all else fails, find a good mechanic who knows old cars. Never let anyone younger than your car work on it :D
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PostPost by: brassrngfm » Mon Jul 19, 2004 8:07 pm

Robb - You can certainly do it yourself. I agree about comments on all the other settings and the CO meter. I also purchased a paperback book on Tuning Webers by Des Hammill which was quite clear and worth the money. I'd also recommend taking a few minutes to do an inventory of what Weber parts your carb has internally. If the manual or book doesn't help, then the first question people will have are what size chokes, etc you have in the carb. While you're at it - you can check to see if the parts/tubes/jets have any foreign matter in them that would cause a rough idle. I had a Mercedes many years ago and the Dealer/Robber said I needed a new $2,000 carburator to fix a rough idle problem. It ended up being a small piece of dirt in an emulsion tube which took me about 1/2 hour to find and cost me nothing to fix! #$%@*&^ Dealer!! My 65 Elan ran a little rough for a while on the new engine but has now smoothed out quite nicely. Good luck.
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PostPost by: 1964 S1 » Mon Jul 19, 2004 8:20 pm

Welcome to Lotus Land ! IF your car runs strong and fast up through the gears and only runs rough at idle, I think it's your carbs.
Yes 5 inch clearance is right and remember, the exhaust down the middle is lower still. I make sure all muffler and pipe clamps are not pointed down, put the nuts on the side or top wherever possible and don't drive over debris/dead animals dead center.
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PostPost by: robb4100 » Mon Jul 19, 2004 11:19 pm

Wow, thanks for the great advice. I will certainly get the weber tuning book, flow meter and CO meter. This last part is where my true ignorance shows through. What is the CO meter for. I don't see it in the shop manual.

The car does run strong through all the gears (a little though in first 'cause I believe it has the 3.55 with the close gearbox- wants to do 40+ in first). Have not yet but will check the timing.

Thanks again for the great advice and I'll give it a try.


R :Robb
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PostPost by: robb4100 » Tue Jul 20, 2004 3:32 am

Guys,

The car had been changed over to electonic ignition. I checked the plug gaps and they were all 0.030 or greater and the plugs were wet. This did not seem right so I reset to 0.026 (middle of the standard range) and all hell broke loose. Car would start but could not generate any power. I presume that this means that the carbs were calibrated to match the larger plug gap. . Note the plugs were not wet at 0.026. Do these changes and effects make sense?


I did not have time to adjust the carbs and moreover did not want to get too far into screwing things up. I punted and reset the plugs to 0.030 and she is running as she did before the change. I do not have the tools in hand to balence the carb and the car will be going to a vintage car mechanic next week for a thourough going over, so will probably leave the problem to him, but am willing to try a couple of things. Does it do any good to check the timing with the gaps so large?

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PostPost by: cliveyboy » Tue Jul 20, 2004 6:50 am

I have just bought a four coloumn manometer from my local dellorto specialist. Its great as I can see what is happening in all four barrels at once and they screw straight into the carbs with out removing the airbox. Its so much quicker and only cost a few pounds more than a good single balancer. Its called a Carbtune II and comes with adaptors to fit Weber or Dellortos.
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PostPost by: steveww » Tue Jul 20, 2004 8:38 am

With electronic ignition and a sports coil you can use a bigger plug gap as you have more spark power. The bigger gap will give you a bigger spark and better ignite the mixture. I use 0.03 (0.8mm) with my electronic points & sports coil.

A CO meter measures the Carbon Monoxide in the exhaust gas. For power you want the mixture a bit rich somewhere around 4% should be good.

Not sure if you are in the UK? You can get the Gunson CO meter new for about ?60 or less if you go for used from ebay.
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PostPost by: types26/36 » Tue Jul 20, 2004 10:59 am

Robb,
Sounds a bit odd, the difference between plug gaps of .026" to .030" = .004" Generally standard engines are not that temperamental that it would make such a great difference to the running. I could better underststand it if you were increasing the gap but even then I have seen engines running O.K. with gaps far greater and worn out plugs. If the ign system is in good condition (plugs/leads/dist cap/connections/coil/power supply etc) a standard system would be O.K. with a .030 gap and I note you have electronic ign. I think you have other problems and dont just assume its the carbs, first make sure the electrics are spot on.
Can't comment on the wet plugs........oil? petrol? even water!
You can check the timing as the plug gap is unlikely to make any difference when you are talking such small amounts.
In conclusion as some one else said make sure all settings and components are good before pulling the carbs apart.
Rgds Brian.
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PostPost by: worzel » Tue Jul 27, 2004 5:45 pm

If you cannot get hold of a manometer consider the device sold by BurtonPower- it's a very sensitive airflow meter- dead easy to use and very accurate- cost me about ?50 and it takes only about 5 minutes to balance the throttles'

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PostPost by: robb4100 » Wed Jul 28, 2004 3:57 pm

:D Thank you all for the great info! I have soo much to learn!!!!! My girl is in the shop for a complete physical and we'll see what they have to say.
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