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#1 Random failure to start
Posted: Sun Aug 16, 2015 9:13 pm
by LeffeBrune
On the road with my S1 4.2. On Thursday and Friday experienced problems starting the car when the motor was warm. Normally, car started well but on two occasions it did do not. I tried various things. On the first day, it eventually worked after I tried the choke, then put the chocke back in, and started with the gas peddel pressed down. On the second day, I cleaned the plugs and then succeeded with the same method as described above. On both days, it was very hot (more than 35 degrees celsius) and I had parked the car for about 45 min.
Yesterday, great tour. All fine. Today, much cooler (less than 20 degrees). 350 km. 3 stops (between 5 and 30 min). All fine. Arrive a hotel. Check in. Get key for garage. Try starting car to park. Not luck. Try again 30, 60, 120 min later. Nothing.
I have a feeling that the car does not get petrol. Ignition is a 123 and starter is running fast.
BTW: Starting the car from cold in the morning has NEVER been a problem.
Any help appreciated.
Thanks.
Georg
#2
Posted: Sun Aug 16, 2015 10:04 pm
by Heuer
Try changing the coil - they can break down with heat and reform when cold.
#3
Posted: Mon Aug 17, 2015 5:04 pm
by LeffeBrune
Thanks, David. Turned out that the problem was a different one. The starter did not connect with the flywheel. We moved the car about half a meter in third gear, which resulted in the flywheel being in a slightly different position. The starter then connected and the car is running again.
Obviously, this is not a permanent solution, and I need to check (or have someone check) whether the root of the problem is the starter or the flywheel.
#4
Posted: Mon Aug 17, 2015 5:12 pm
by David Oslo
Aha, so that's what you meant when you said "starter is running fast", it was in fact spinning freely, right? I thought you meant engine was turning over fast, but not catching through missing fuel or spark.
Maybe the starter needs pulling from the car and a good degrease and fresh lubrication of the starter pinion (gear) and associated springs. Maybe it's just sticking on it's shaft and not engaging properly.
Worth a try and not too bad a job.
#5
Posted: Mon Aug 17, 2015 5:18 pm
by Heuer
You probably have some broken teeth on the flywheel gear which means engine out, flywheel machined and new year ring fitted. Probably a good idea to replace the starter as well because if one gear is damaged so will the other be. Get under the car and you should be able to check the ring gear through the inspection hole at the bottom of the bell housing.
#6
Posted: Mon Aug 17, 2015 5:53 pm
by LeffeBrune
Thanks and sorry for my imprecise and non-technical explanation.
The good thing is that the car is still under warranty. The garage/dealer where I bought it from had redone the engine and told me today that he had fixed a new flywheel at that occasion.
#7
Posted: Tue Mar 15, 2016 1:45 pm
by paydase
I wish to share a similar experience.
On Sunday I made a small trip with my 3.8 FHC.
Weather was cool and the engine ran great.
Until I went back and was stuck in traffic jams in the city, the engine starting to have occasional misfires when opening the throttle, as if I had a fuel supply issue.
Stopped for refuelling and had difficulty to restart the engine. I was surprised by the quick spinning of the starter. Fortunately, the engine started on 3rd attempt.
Back to the garage, engine stopped during maneuver, again due to apparent fuel starvation.
And then, impossible to restart. I tried several times. Again I was surprised by the apparent very rapid spinning of the starter, as if there was no engine resistance. Finally gave up and pushed the car in the garage (ouch, lucky it was a few meters only and horizontal!).
Looked at the forum, trying to understand for investigation.
Noticed that most issues alike relate to ignition, often due to the coil or the points, but saw the present thread, fearing I may have flying wheel gear teeth broken...
This morning, with battery fully loaded, I went to make a new trial, full choke as if nothing had happened.
And luckyly, the engine started at second attempt.
Now I believe I may have an ignition issue to be addressed that happens when engine is hot, be it the coil or the points.
Will look at that.
#8 Starting issues
Posted: Tue Mar 15, 2016 2:31 pm
by cactusman
Hi. Assuming it is not the starter then I would suspect either a dodgy coil or rotor arm. The rotor arms with a brass rivet holding the brass connector arm to the plastic top are well known to break down when hot. Causes misfires and makes the car very hard or impossible to start when hot. Leave for 20 mins to cool and the problem goes away. Get yourself a genuine red rotor arm with no rivet. They are a very few pounds. Take a minute to fit.
If this does not cure then it is worth while changing the coil but I would start with a new rotor arm.
#9
Posted: Tue Mar 15, 2016 5:21 pm
by caveman
Serge,
I had similar problem a few years ago now. It turned out to be my rotor arm breaking down when hot. New Lucas rotor arm sorted the problem with no repeat since. I carry a spare in my boot along with a coil as these are easy replacements/fault diagnosis out on the road.
#10 Starting issues
Posted: Tue Mar 15, 2016 6:42 pm
by cactusman
Exactly Steve. Trouble is most of the new "Lucas" branded arms are reproductions and have a rivet. They are to be avoided...the the genuine Lucas arms never had a rivet.
So if you can get a new old stock genuine Lucas arm it will be fine but beware of reproduction arms with a rivet.
The "red" arms have no rivet and should be fine although I have heard even these are now being faked!!!
#11
Posted: Tue Mar 15, 2016 6:51 pm
by mgcjag
If you want tne original red rotor....go to the distributor doctor
http://www.distributordoctor.com
#12
Posted: Tue Mar 15, 2016 9:21 pm
by caveman
No rivets in my car. Thankfully I did a lot of research at the time and genuine Lucas new old stock (NOS) were only fractionally dearer than inferior riveted types. No brainer really and something I aim for when purchasing spare parts now.
#13 Rotor arm
Posted: Tue Mar 15, 2016 10:19 pm
by cactusman
The Lucas part no is 418726 I believe. Plenty of crappy riveted repro parts on fleabay but there are a few genuine nos parts and the dizzy doc does the red ones.
#14
Posted: Tue Mar 15, 2016 11:53 pm
by Heuer
Distributor Doctor rotor arms are superb and the equal or better than the original Lucas. So good in fact someone is making (poor) reproductions

Either buy direct or make sure they have 'DD' in raised letters on the red plastic.
#15
Posted: Wed Mar 16, 2016 12:29 am
by paydase
Many thanks to all of you.
Invaluable forum :D
#16 Rotor arm
Posted: Wed Mar 16, 2016 7:40 am
by cactusman
DD one in mine. Just the job. There are fakes about....red with a rivet apparently?
Mine also has a power spark to do away with the points....after three years still good too.
#17
Posted: Wed Mar 23, 2016 8:55 pm
by caveman
Spoke with Martin at DD today, really nice chap and very helpful. Busy with orders as you can imagine. His contact details are below and he charges ?6.00 + vat for 1965 4.2 Red Rotor Arm to give you a rough idea. Delivery is extra. No excuse at that price!
Martin Jay
01984 629540
Distributor Doctor Ltd
Unit 8 Old Brewery Road Wiveliscombe
Taunton
Somerset
TA4 2PW
http://www.distributordoctor.com
#18
Posted: Fri Mar 25, 2016 10:44 pm
by caveman