[Healeys] Engine problem

[Michael Salter]

Hi Jack,
The problem that you are experiencing is called "run on" and is very common
in older cars. 
It is caused by spontaneous combustion of the incoming charge as a result of
the heat in the combustion chambers, high compressions and sometimes local
"hot spots". I think it is made worse by modern, lead free, fuels. It does
not happen on modern cars because the fuel injectors stop operating when you
turn off the ignition so there is nothing to burn.
Some measures can be taken to eliminate run on but, in some cars, in my
experience often BJ8s, it just cannot be beaten. 
Some of the things that may help are:
1. Ensure that the idle speed is as low as you can get it. 
2. Use good quality fuel.
3. Let the engine idle a few seconds before turning off
4. Ensure that the cooling system is keeping the engine temperature in the
180 - 200 range.
I have developed the habit of turning the engine off with the car is 4th
gear and gently releasing the clutch as I turn off the ignition. This
essentially stalls the engine as it shuts down and will prevent the
shuddering which can cause engine damage, and the risk of the engine running
backwards on its last gasp and spraying a load of exhaust gas, mixed with
raw fuel out through the air filters.

Michael Salter
100S (1955)
3000 Mk111(1965)
100 (1953)
AHX12 (1953)
Bugeye (1961)
http://www.netbug.net/blogmichael/

-----Original Message-----
From: healeys-bounces+msalter=precisionsportscar.com at autox.team.net
[mailto:healeys-bounces+msalter=precisionsportscar.com at autox.team.net] On
Behalf Of Ph.J.Aeckerlin
Sent: August 20, 2007 8:32 AM
To: Healey forum
Subject: [Healeys] Engine problem

Friends,
Wednesday last I received my license plates and at last, after 6 and a 
half years, I am able to take my BJ8 out on the road. It's a fantastic 
experience but I have one point which worries me. When I switch the 
ignition off after a run of, say, half an hour, the engine continues to 
run for a few seconds. Very irregular, the engine shakes like hell until 
it dies out. I therefore now put my foot on the brake and release the 
clutch whilst in 1st gear - that does stop the engine but I don't like 
this kind of rough treatment.
The ignition is a 123 electronic ignition, the carbs were synchronized 
by a pro, the engine was overhauled by a pro - what can be the reason 
and what can I do to stop it?
Many thanks in advance for your reaction.
Regards,
Jack Aeckerlin, The Netherlands
1964 BJ8 29432
_______________________________________________
msalter at precisionsportscar.com