Lotus Elan

Hot rough running

PostPost by: terryp » Wed Feb 06, 2008 3:42 pm

Kevin
I have a recuperating bottle with the overflow going straight into about 25mm of coolant. Is this the same? There are never any bubbles in this?

Terry
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PostPost by: ppnelan » Wed Feb 06, 2008 4:33 pm

How about something electrical e.g. dodgy distributor advance mechanism, (or a faulty coil, condenser, or rotor arm, but I see you've already replaced these...)?
Or fan cutting in drains the power from the ignition system...?!

:arrow: Matthew
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PostPost by: 1964 S1 » Wed Feb 06, 2008 10:06 pm

It doesn't sound to me like the car is actually overheating. I'll stick to my sticking choke or ??? timing chain off one tooth is a stretch but... easy to check. Check ALL the easier solutions first. Taking the thermostat out for a test run/check is a very good idea. Good Luck, I think it's going to be something simple.
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PostPost by: denicholls2 » Thu Feb 07, 2008 4:15 pm

I see nothing in your posts to indicate:

- A failed head gasket
- A blocked thermostat
- A blocked radiator

While some of these are possibly present, I'll offer they have nothing to do with your problem unless you have a faulty temperature gauge.

Note: In my experience, Brit thermostats of this era DO fail closed, not open. Modern thermostats fail open.

At 90c, this engine isn't overheating. Forget about radiator problems until it overheats. Water boils at 100c, pressurized water higher depending on the pressure. Unless it's letting steam, forget about it being too hot.

I know you have replaced spark-related bits, but you may have some bad ones; there seem to be frequent reports of defective new parts. Defective rotors, for example, seem rife on this list. And an NOS condenser may still be 40 years old and worthless.

Assuming the things people are focusing on aren't the problem, the likely areas IMO are:

- Bad condenser
- Bad coil
- Bad mixture (slightly too rich for warm idle.)

Mixture is last so you don't mess it up. Before touching it, run the engine for a good period off idle (drive it) and stop it without idling much at all before pulling the plugs. They should not be wet-fouled or sooty, if they are you're getting warmer...

Good luck!
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PostPost by: alaric » Thu Feb 07, 2008 9:14 pm

Hi.

I know you mention that you have a manometer and co meter etc, but are you sure that the carbs are set up properly - are they balanced for flow and mixture? As a check you could try adjusting one of the mixture screws. You should be able to hear the difference in tickover just by adjusting one of them if all is set up properly. If it doesn't make much difference, then I'd start with that. There's a detailed procedure in a book that I got from Eurocarbs off ebay - can look up the title if of interest.

Sean.
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PostPost by: kstrutt11 » Fri Feb 08, 2008 2:31 pm

Terry,
As someone else has said there appears to be nothing wrong with the head gasket etc, I have a similar car to yours and the temp gauge does move around depdent upon driving conditions, this can be disconcerting if you are used to modern massively damped gauges, If it does not boil over I would suggest the cooling system is not an immediate problem.
As well as checking all the parts mentioned I wouuld check the CO when it is running lumpy(this will tell you if you have a air leak or fuel flow problem) also if you then key it off and remove the plugs are they all the same colour? the best way I have found to set mixture is with a colour tune as CO at the tailpipe does not tell you what is going on each cylinder.
As well as the service items already mentioned I would also check the distributor base plate earthing, ignition coil and Carb O rings(spray a little
eazy start around them with the engine running to check for leaks).

Kevin S (73 +2S130)
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PostPost by: terryp » Fri Feb 08, 2008 3:32 pm

Thanks for all your replys.
I took the car for a run and then pulled the plugs. All were the same and slightly (not overly so) sooty, but definately sooty.
What I can't figure is I was under the impression that the mixture control screws are only for idling, the rest being either the pump jet or other fixed jets. So lumpy tick over yes, but surely not lumpy running? Could my main/air corrector be wrong? I have got K&N filters which I fitted to get the CO2 down to a passible level for the controle technique here in France.
It seems to weird as the car runs beautiful up to this point.

So I'm going to check all the earthing and the ignition bits and for air leaks
I've also bought some better quality Viton tipped needle valves (I went cheap before and didn't realise there were different qualities).
Also as I'm now paraniod and the old one does look rough I've bought a new 3 row radiator from Susan Miller - its coming from the UK with friends next Friday.
So fingers crossed in the next couple of weeks.

Many thanks to all

Terry
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PostPost by: Craig Elliott » Fri Feb 08, 2008 3:37 pm

Terry - what fuel are you using?

C
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PostPost by: terryp » Fri Feb 08, 2008 3:42 pm

Craig
Super unleaded with Castrol standard Lead Ad Mixture

What should I be using ??????

Terry
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PostPost by: tdafforn » Fri Feb 08, 2008 4:14 pm

If you are going to start playing around with jets, become member of the sidedraft_central group on Yahoo. They know more about webers and dellortos than I will ever know.
They also have some very clear instructions on setting up the carbs, that are developed from scientific observation.
cheers
tim
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PostPost by: twincamman » Fri Feb 08, 2008 5:35 pm

Before YOU GET ALL SILLY AND SPEND MORE MONEY -------CHECK ------THE JETS ----115 hp motor= emulsion tube f 11- main 120- air correct 180 - THE IDLE IS OUT 1 1/4 TURN AND ADJUST WARM ---the mantra is ----CARBURETTOR IS FRENCH FRENCH FOR ---LEAVE IT ALONE carbs never go wrong -but once you diddle them you have added another problem to the equitation ---- --DID YOU CHECK THE WATER PUMP FOR PLAY ??? ED
dont close your eyes --you will miss the crash
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PostPost by: terryp » Sat Feb 09, 2008 2:45 pm

Hello
No play in waterpump, car is a 130 big valve and has standard jets as Lotus workshop manual.
I had to have the carbs adjusted to pass the controle technique here in France. Before adjustment it had 6% CO2 and it was a fail i.e. take car back to the UK and sell. It was a bit of luck the french garage had a manermeter as well as the anti pollotion check. It only just passed and with the air cleaner off and could not be improved upon 4% CO2. I fitted the K&Ns after as to run without an air cleaner would be a bit silly.

Terry
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PostPost by: twincamman » Sat Feb 09, 2008 5:41 pm

sound like its too lean --makes things run hot---ed
dont close your eyes --you will miss the crash
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PostPost by: terryp » Sun Feb 10, 2008 8:56 am

Hello
But the plugs are slightly sooty !

Terry
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PostPost by: twincamman » Sun Feb 10, 2008 1:17 pm

that could nean its rich at idle and lean off idle ---ed
dont close your eyes --you will miss the crash
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