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Barry Brears
Experienced User
Username: turney_2009

Post Number: 48
Registered: 8-2009
Posted on Tuesday, 31 August, 2010 - 14:16:   Edit PostDelete PostView Post/Check IP

Hi More problems with my Bentley SBH17291,its now occasionly misfiring at low revs under load in drive,on a 6km drive around town happens about 3 or 4 times usually on slight gradients.I have checked advance and retard also put in new plugs,cleaned carburetors especially pots adjusted volume screw as per W/manual and also mixture screw.Then I disconnected fuel weakening device,unable to get dizzy cap off its jammed on tight frightened of cracking the cap (any suggestions)would like to check points.So all advice greatly received.Engine doesn't seem to run smooth at low revs just sounds like a badly tuned V8 which of course it is,at high revs perfect!!!!.
Regards Barry
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Mark Taxis
Experienced User
Username: mark_taxis

Post Number: 40
Registered: 4-2007
Posted on Tuesday, 31 August, 2010 - 14:36:   Edit PostDelete PostView Post/Check IP

Hi Barry
Check the inlet manifold gaskets, sounds like there may be an air leak there
rgds
Mark
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Barry Brears
Experienced User
Username: turney_2009

Post Number: 49
Registered: 8-2009
Posted on Wednesday, 01 September, 2010 - 16:12:   Edit PostDelete PostView Post/Check IP

Thanks Mark have done that still have the problem a suggestion by a friend is to check ignition leads.Secondly and please excuse my ignorance, volume screw whats its function is it something to do with air intake.
Regards Barry
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Benoit Leus
Experienced User
Username: benoitleus

Post Number: 12
Registered: 6-2009
Posted on Wednesday, 01 September, 2010 - 18:56:   Edit PostDelete PostView Post/Check IP

Hi Barry,
my Shadow also didn't run smoothly at low revs and idled roughly. After a lot of searching and head scratching it seems the A1 cylinder exhaust valve is leaking. What colour do the plugs have ?

Benoit
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Barry Brears
Experienced User
Username: turney_2009

Post Number: 50
Registered: 8-2009
Posted on Wednesday, 01 September, 2010 - 19:08:   Edit PostDelete PostView Post/Check IP

Hi Benoit,The colour of the plugs well they are a black sooty colour which says to me that the car is running a liitle rich.When you say the exhaust valve is leaking do you mean the exhaust manifold?This afternoon I checked all the ignition leads and they are all producing a good spark.I did notice one of the exhaust manifold set screws was loose maybe thats the next thing to replace the gaskets,Ho Hum love these old cars.

Barry
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Benoit Leus
Experienced User
Username: benoitleus

Post Number: 13
Registered: 6-2009
Posted on Wednesday, 01 September, 2010 - 23:20:   Edit PostDelete PostView Post/Check IP

Hi Barry,
I mean the actual exhaust valve, inside the cylinder. Let the engine idle when it's hot and remove the spark plug leads from the distributor cap one at a time. Normally the engine will start running a little rough. If however nothing happens then you know you've got a problem with that cylinder, be it electrical or mechanical.
Benoit

(Message edited by BenoitLeus on 01 September 2010)
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Barry Brears
Frequent User
Username: turney_2009

Post Number: 51
Registered: 8-2009
Posted on Saturday, 04 September, 2010 - 13:14:   Edit PostDelete PostView Post/Check IP

Hi Gentlemen,Well I may have fixed the problem the car seems to be running ok after a 6 km run.The spark plugs were incorrect as was the timing as was fuel mixture,as was dirty points.I have orderd a new coil just to be on the safe side.Thanks for your input.

Barry