Lotus Elan

Won't Start!

PostPost by: Flying Banana » Wed Jul 28, 2021 9:43 am

Hi,

I've trawled the forum looking for various hints and tips as to potential solutions to my non starting problem but I'm stuck!

My car is a '66 S3 with 40DCOE18s (recently ultrasonically cleaned and fully overhauled) with a 123 bluetooth distributor fitted. The car also has a facet electric pump and a regulator fitted set to 1.5 psi.The car cranks and tries to start, but won't catch. The exhaust manifold is getting warm, so there is some combustion happening!

So far, I've checked the following:
- aligned the timing marks between the front pulley and the front case to TDC
- cam lobes for number 4 cylinder are facing each other
- seen that the rotor arm is pointing directly towards the block (12 o'clock if I were leaning over the right hand front wing looking down at the dizzy)
- observed via a mirror that the pump jets are working (I also have fuel on the plugs)
- had #1 spark plug out and earthed on the block to check for a spark
- the distributor cap has all the HT leads exiting towards the rear of the engine (towards the bulkhead)
- new fuel in the tank (I've drained 2x refills of the float bowls to try and remove what may have been stale fuel)
- ignition curve loaded to the dizzy starts at 0 degrees at 500 revs then rises to 12 degrees at 1000 rpm and continue up from there.
- checked the HT to dizzy cap connection order and ensured the correct HT lead is going to the correct plug (1342)
- carbs setup such that the first progression hole is covered by the throttle plate and the mixture screws are wound out 1.5 turns from fully in. This should get me started?

What am I missing?! From the pops and bangs I think I may have the dizzy installed 180 degrees out, which means I am firing on the exhaust stroke - which is generating the heat in the manifold. However, the rotor arm is facing in the correct place when the TDC mark on the front pulley lines up with the mark on the front case and #4 lobes are pointing inwards.

I'm more than happy to start again with a completely fresh check list in case I've missed anything obvious (or need to re check something).
1966 FHC S3 Elan
1969 Alfa Giulia Stepnose - halfway Alfaholics GTA-R
1998 Caterham 7 Superlight R
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PostPost by: rgh0 » Wed Jul 28, 2021 10:58 am

What is the static ignition timing and the advance curve quoted sounds to quick ? You should have around 12 engine degrees before TDC static with a linear advance from 1000 rpm engine speed to around a total of 28 engine degrees at 3000 to 4000 rpm engine speed as a starting point. This 28 degrees includes the 12 degrees static advance.

cheers
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PostPost by: Flying Banana » Wed Jul 28, 2021 11:08 am

Hi Rohan,

I set the engine to TDC then set the curve in the 123 dizzy relative to this point, (rather than add an advance curve to a 12 degree BTDC static timing setting). To this end, I am running zero advance for cranking (and starting).

Cheers
1966 FHC S3 Elan
1969 Alfa Giulia Stepnose - halfway Alfaholics GTA-R
1998 Caterham 7 Superlight R
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PostPost by: rgh0 » Wed Jul 28, 2021 11:22 am

Flying Banana wrote:Hi Rohan,

I set the engine to TDC then set the curve in the 123 dizzy relative to this point, (rather than add an advance curve to a 12 degree BTDC static timing setting). To this end, I am running zero advance for cranking (and starting).

Cheers


you need some static advance

cheers
Rohan
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PostPost by: Flying Banana » Wed Jul 28, 2021 11:24 am

I've just added 10 degrees as a starting point at 500 revs and now the car gives a load of loud pops/bangs out of the exhaust whilst cranking. Is this a sign of unburnt fuel igniting in the exhaust?
1966 FHC S3 Elan
1969 Alfa Giulia Stepnose - halfway Alfaholics GTA-R
1998 Caterham 7 Superlight R
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PostPost by: gjz30075 » Wed Jul 28, 2021 11:57 am

"seen that the rotor arm is pointing directly towards the block (12 o'clock if I were leaning over the right hand front wing looking down at the dizzy)"

Is it pointing at the #1 spark plug wire?
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PostPost by: Flying Banana » Wed Jul 28, 2021 12:03 pm

gjz30075 wrote:"seen that the rotor arm is pointing directly towards the block (12 o'clock if I were leaning over the right hand front wing looking down at the dizzy)"

Is it pointing at the #1 spark plug wire?


Hi. Just before
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PostPost by: Andy8421 » Wed Jul 28, 2021 1:28 pm

Flying Banana wrote:
gjz30075 wrote:"seen that the rotor arm is pointing directly towards the block (12 o'clock if I were leaning over the right hand front wing looking down at the dizzy)"

Is it pointing at the #1 spark plug wire?


Hi. Just before


Your symptoms are consistent with the plug leads being on the wrong plugs, but assuming you are 100% sure you have got that right, it is possible you don't have the rotor arm aligned properly. Standard Lucas distributors do this for you because of the positioning of the points, the distributor cap and rotor arm are all keyed into position relative to each other. I don't know how the 123 distributor does this and whether it is adjustable or not.

Thinking this through, the rotor arm goes anti-clock when viewed from the top, so as advance is added to the spark position, the rotor arm will move clockwise relative to the position of the contacts in the distributor cap. So is your 'just before' comment clockwise or anti-clock? If I have my logic correct, it needs to be 'just before' clockwise at TDC and zero advance.

Having said all this, a decent spark should be able to cope with a slightly misaligned rotor arm and just jump the gap.

I am not sure I agree with Rohan's comments on zero advance at cranking and starting. I think that should work, and would have thought would make life easier for the starter, but I could be wrong.

Good luck.
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PostPost by: Flying Banana » Thu Jul 29, 2021 8:57 am

Got it started!

Despite aligning the green LED per the 123 ignition instructions, the distributor required rotating around 15 degrees prior to starting, whereupon it started in about 2 revolutions of the starter. Phew
1966 FHC S3 Elan
1969 Alfa Giulia Stepnose - halfway Alfaholics GTA-R
1998 Caterham 7 Superlight R
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