Bentley Eight Firing order and HT lead connections - Rolls-Royce and Bentley Forums
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 11 (permalink) Old 09-16-2014, 11:41 AM Thread Starter
New Member
 
Join Date: Sep 2014
Posts: 9
Bentley Eight Firing order and HT lead connections

Hi guys,

Does anyone have a diagram showing which plug lead goes where (i.e from the dizzy cap to the plugs). I cant find a diagram anywhere.....even a doodle on a bit of paper and upload a pic would be awesome. I've looked at the online service manual, which states firing order is A1 A3 B3 A2 B2 B1 A4 B4. It also states that the front Drivers side cyl is A1 so I assume the cylinder order is:

A1 A2 A3 A4
B1 B2 B3 B4

But there isn't anything showing what is the corresponding connection on the distributor cap.......if that makes sense?

My 1988 Bentley Eight has a lumpy idle, it goes away when revs are increased so I think its either a fuel/air mix issue, a dirty dizzy cap or vacuum leak somewhere.......I've only just bought the car.

However, I'd like to check that the plug leads are all where they should be and that the last owner/garage hasn't put them on the wrong connections messing up the firing order.

Any help greatly appreciated

Alastair.
black t top is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old 09-16-2014, 12:15 PM
Senior Member
 
guyslp's Avatar
 
Join Date: Aug 2007
Location: Staunton, VA - USA
Posts: 2,955
Alastair,

In order to answer your questions definitively it's essential to know what model year your car is. Even better, give us the SZ Chassis Number Derivation from VIN, which in your case is definitely EBJ-<last five digits of VIN>.

The A-bank on these cars is always the right side of the engine if you are seated at the driver's position (or, of course, that means left side were you standing in front of the grille). Your firing order is completely dependent on your model year:



You've got the correct order for your car, but I'm posting the above for later readers who have cars prior to the 1986 model year.

I can't find the diagram you're seeking, but I don't think the order of the HT leads differs from the SY series cars, though I need someone to confirm that. If that's the case, I can give you which lead goes to which spot on the distributor. I have to believe that diagram exists somewhere, but I'm not finding the magic keywords to turn it up in a search of the workshop manual.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


guyslp is offline  
post #3 of 11 (permalink) Old 09-16-2014, 07:03 PM
Senior Member
 
guyslp's Avatar
 
Join Date: Aug 2007
Location: Staunton, VA - USA
Posts: 2,955
A follow-up regarding locating the leads on the distributor cap . . .

Everyone I've communicated with indicates that, if you look at the distributor cap as though it were a clock and as though you're sticking your head through the windshield to view it, the A1 position is consistently at 1 o'clock. Since the rotor arm rotates counterclockwise you simply plug in the remaining leads based upon the correct firing order for your car, starting with A1 at 1 o'clock and working your way around.

Also, which makes perfect sense, it doesn't really matter if you start with A1 in another spot so long as you do the firing order sequencing correctly after wherever you placed A1, working counterclockwise.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


guyslp is offline  
 
post #4 of 11 (permalink) Old 09-17-2014, 06:40 AM Thread Starter
New Member
 
Join Date: Sep 2014
Posts: 9
Hi Brian,

Appreciate the information, I will check the chassis number for the car tonight when I get home and get back to you.

Based on what you said I've drawn up the following diagram, showing firing order and cylinder location/HT lead connections......can you just check that this is correct:

Cheers,
Alastair.
black t top is offline  
post #5 of 11 (permalink) Old 09-17-2014, 09:07 AM
Member
 
Join Date: Sep 2010
Location: Nottingham UK
Posts: 35
Alistair,

In your firing order, the second A3 should be A2. I also thought that the direction of rotation of the rotor arm was anti-clockwise so shouldn't the firing order be reversed?

Kind regards,
Chris
Chrisb is offline  
post #6 of 11 (permalink) Old 09-17-2014, 10:17 AM
Senior Member
 
guyslp's Avatar
 
Join Date: Aug 2007
Location: Staunton, VA - USA
Posts: 2,955
Alastair,

Chris is correct and here's my revision (rotated to suit me, in this case). I did not try to erase and redraw the lines from each rotor lead position to its respective cylinder. The cylinder designations are correct.


Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


guyslp is offline  
post #7 of 11 (permalink) Old 09-18-2014, 05:11 AM Thread Starter
New Member
 
Join Date: Sep 2014
Posts: 9
Hi Chris/Brian,

Brilliant, just as well I checked this or I'd have made a complete mess of it!

I've amended the diagram so I think this one is now correct??

[/i]
black t top is offline  
post #8 of 11 (permalink) Old 09-18-2014, 06:22 AM
Member
 
Join Date: Sep 2010
Location: Nottingham UK
Posts: 35
Hi Alastair,

Yes, that looks right now.

Kind regards,
Chris
Chrisb is offline  
post #9 of 11 (permalink) Old 09-19-2014, 11:07 AM Thread Starter
New Member
 
Join Date: Sep 2014
Posts: 9
Cheers Chris.......hopefully a clean and check over of the car/arm/plugs and leads will sort the lumpy idle once it's warmed up.

Then I can move onto the next problem, a water pump that doesn't drip when the car is running or is hot, but starts randomly dripping after 2 or 3 days of standing, but only when the weather is cold.......worst case it'll need a new water pump, but I'm hoping it'll be the O ring that's failed and when the car is hot the metal is expanding enough to seal it, when it gets cold, the metal contracts and it seeps.
black t top is offline  
post #10 of 11 (permalink) Old 09-19-2014, 11:52 AM
Senior Member
 
guyslp's Avatar
 
Join Date: Aug 2007
Location: Staunton, VA - USA
Posts: 2,955
Alastair,

Definitely have a look at what your HT leads are doing after dark. It's amazing what you can, and often do, sight when viewing these things when there's no other light around to mask sparking where it shouldn't be.

As far as the water pump, it's almost certainly the O-ring and it's the o-ring expansion/contraction more than the metal that makes up the difference when warm/cold. However, I'd definitely price out a replacement water pump as well as the kit. These things are a bit of a pain to overhaul and you can often get a new or rebuilt (from Flying Spares or Introcar) one for not that much more than the seal kits.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


guyslp is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Rolls-Royce and Bentley Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.

SEO by vBSEO 3.6.1