O.K. Paul.
I understand that carbon contamination in the cylinderhead or onto the
piston is causing this.
Now we come to the next step:
what causes the buildup of this carbon:
1 wrong timing - o.k. I understand
2 overall burning oil due to poor engine condition - this is my opinion and
I think with many old MG's the most probable cause. Am I right?
Cheers,
Hans who wants to avoid this with his
'71 BGT
> -----Original Message-----
> From: Paul Hunt [SMTP:paul.hunt1@virgin.net]
> Sent: Thursday, November 11, 1999 11:27 AM
> To: Chris Velardi; Hans Duinhoven; tab julius; steve conley
> Cc: Skye Poier; MG LIST
> Subject: Re: What causes "shutoff shudder"?
>
> When the ignition is off but the engine is still spinning it is sucking in
> exactly the same fuel/air mixture as it was before. If conditions inside
> the combustion chamber allow i.e. glowing carbon or shards of metal, this
> mixture will continue to be ignited, albeit irregularly giving the typical
> shuddering, until the incoming mixture has cooled the combustion chamber
> sufficiently. Tming affects Dieseing because it affect running
> temperature - either too retarded or too advanced will cause higher
> temperatures inside the combustion chamber. Hence timing affects
> Dieseling.
>
> PaulH.
> http://freespace.virgin.net/paul.hunt1/
> (or if that URL doesn't work try )
> (http://194.168.54.52/paul.hunt1)
>
> -----Original Message-----
> From: Chris Velardi <tchris@freewwweb.com>
> To: Hans Duinhoven <H.Duinhoven@simac.nl>; tab julius <tab@penworks.com>;
> steve conley <swconley@foxinternet.net>
> Cc: Skye Poier <skye@ffwd.com>; MG LIST <mgs@autox.team.net>
> Date: 10 November 1999 14:06
> Subject: Re: What causes "shutoff shudder"?
>
>
> >I believe it is due to un-burnt fuel in the combustion chamber, or
> un-burnt
> >fuel exiting the combustion chamber in to the exhaust manifold or headers
> >and combusting due to excessive heat. But I'm not exactly sure why it
> >happens . It used to happen on my '61 A until I retarded the timing. The
> >only way I could shut it off with out the damaging dieseling (engine
> >actually running backwards) was to put it in first and drop the clutch
> and
> >shut the key off at the same time.
> >Chris "V"
> >http://www.xtremedefender.com
> >http://www.extremeforce.com
> >
> >----------
> >>From: Hans Duinhoven <H.Duinhoven@Simac.nl>
> >>To: "'Chris Velardi'" <tchris@freewwweb.com>, Tab Julius
> ><tab@penworks.com>, Steve Conley <swconley@foxinternet.net>
> >>Cc: Skye Poier <skye@ffwd.com>, MG LIST <mgs@autox.team.net>
> >>Subject: RE: What causes "shutoff shudder"?
> >>Date: Wed, Nov 10, 1999, 8:56 AM
> >>
> >
> >>I have heard this more, but don't understand.
> >>At time you switch off the ignition, there are no sparks at the spark
> plug
> >>anymore. Still the engine goes on (like a diesel engine).
> >>Why should the cause of this be found in the incorect timing?
> >>
> >>Cheers,
> >>
> >>Hans
> >>
> >>'71 BGT which does not suffer of dieseling
> >>
> >>> -----Original Message-----
> >>> From: Chris Velardi [SMTP:tchris@freewwweb.com]
> >>> Sent: Wednesday, November 10, 1999 2:52 PM
> >>> To: Tab Julius; Steve Conley
> >>> Cc: Skye Poier; MG LIST
> >>> Subject: Re: What causes "shutoff shudder"?
> >>>
> >>> Dieseling is most commonly caused by incorrect timing
> >>> Chris "V"
> >>> http://www.xtremedefender.com
> >>> http://www.extremeforce.com
> >>>
> >>> ----------
> >>> >From: Tab Julius <tab@penworks.com>
> >>> >To: "Steve Conley" <swconley@foxinternet.net>
> >>> >Cc: "Skye Poier" <skye@ffwd.com>, "MG LIST" <mgs@autox.team.net>
> >>> >Subject: RE: What causes "shutoff shudder"?
> >>> >Date: Wed, Nov 10, 1999, 8:25 AM
> >>> >
> >>>
> >>> >
> >>> >Thanks to all - I've had a number of suggestions, a few have narrowed
> >>> down
> >>> >to this valve, which I will check, but all are good ideas.
> >>> >
> >>> >- Tab
> >>> >
> >>> >
> >>> >At 10:37 PM 11/9/99 -0800, Steve Conley wrote:
> >>> >>The '73-80 models of B have the anti-run on valve. When you (not you
> >>> Skye!)
> >>> >>turn off the engine, you should hear an audible click from the valve
> >>> >>kicking-in. It is located on the passenger side of engine
> compartment
> by
> >>> the
> >>> >>carbon cannister. My '76 had a short period where it would diesel a
> bit
> >>> and
> >>> >>it went away as quickly and mysteriously as it appeared. I just
> shrugged
> >>> my
> >>> >>shoulders and didn't try to figure it out!
> >>> >>
> >>> >> Giving money and power to government is like giving whiskey and
> car
> >>> keys
> >>> >>to teenage boys. -(PJ O'Rourke)
> >>> >>
> >>> >>Steve Conley
> >>> >>Marysville, WA USA
> >>> >>'76 MGB Roadster
> >>> >>GHN5UG393585G
> >>> >>mailto:swconley@foxinternet.net
> >>> >>MGB Online = http://web3.foxinternet.net/swconley
> >>> >>
> >>> >>
> >>> >>
> >>> >>-----Original Message-----
> >>> >>From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net]On
> >>> >>Behalf Of Skye Poier
> >>> >>Sent: Tuesday, November 09, 1999 1:41 PM
> >>> >>To: Tab Julius
> >>> >>Cc: MG Nuts
> >>> >>Subject: Re: What causes "shutoff shudder"?
> >>> >>
> >>> >>
> >>> >>Word on the street is that Tab Julius said:
> >>> >>> Turning off my ignition, my 78B's engine will often give me a few
> >>> shudders
> >>> >>> before it decides to shut off for good. This is an effect I
> remember
> >>> >>> fondly from other older manual, probably non-fuel-injected cars
> (most
> >>> >>> notably my long-gone yellow 72 beetle). Releasing the clutch (to
> a
> >>> gear)
> >>> >>> causes it to shut off quicker (okay, stall).
> >>> >>
> >>> >>The common term for this is "deiseling" or "run-on". The engine is
> hot
> >>> >>enough
> >>> >>to continue to ignite air/fuel even though there is no spark. I
> >>> >>could be wrong, but I think your 78 should have an anti-runon
> valve..
> >>> >>the gulp valve?.. I don't know a lot about the emissions systems on
> >>> >>later cars.
> >>> >>
> >>> >>Skye
> >>> >>
> >>> >>--
> >>> >>1966 MGB - GHN3L Safety Fast! __,__\__
> >>> >>The MGB Experience http://www.mgb.bc.ca/ (_o____o_)
> >>> >>
> >>> >>
> >>> >>
> >>> >
> >>
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