XK120 XK140 XK150 1948 - 1962

123 ignition fitted, running v rough

 
  #1  
Old 10-09-2018, 04:50 PM
Junior Member
Thread Starter
Join Date: Aug 2011
Location: cork
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
Default 123 ignition fitted, running v rough

Hi there,
I fitted a 123 electronic ignition into my xk120 saturday, drove sweetly for about 25 miles. Started it today and its running very rough and lumpy! Noticed after the run yesterday it was quite lumpy on tick over but put it down to the fact that the car hasn't been driven in properly years (old distributer would fail after 5/6 miles hence 123) any ideas/?
Regards,
Scott
 
  #2  
Old 10-18-2018, 01:38 PM
Member
Join Date: Jan 2011
Location: The Netherlands
Posts: 71
Received 11 Likes on 11 Posts
Default

Hello,

What settings on the 123 did U use, the default does not match a 3.4 of the XK120.
On my XK140 I have put it on 3, but you have to test for the best settings.
Did you adjust it on 10 degrees before DTC, where that the green light goes on.
I have a 123 on all my 3 old jags ( xk140, xk150 3.8, s-type 3.8 ), never had a problem.

regards,
Peter Jan
 
  #3  
Old 05-08-2019, 01:28 PM
Junior Member
Join Date: Jul 2018
Posts: 22
Likes: 0
Received 1 Like on 1 Post
Default

Hi Peter,
I think it has been set to 4 as recommended by the people I bought it from for the xk120.. it's running very rich also..do the settings on the 123 make that much of a difference? Took it on a 40 mile run yesterday very smooth on the road but lumpy when meeting traffic.. I might adjust the mixture before taking out the distributor again..
Regards Scott
 
  #4  
Old 05-08-2019, 06:14 PM
Senior Member
Join Date: Dec 2011
Location: Southern Califonia
Posts: 164
Received 49 Likes on 34 Posts
Default

Scott,
The idle settings on the 123 are all similar, the curves start to separate at higher RPM. So if your at the recommended 10 degrees static setting, I would check plugs for fuel or oil fouling. Over rich at idle, would be more noticeable when engine is warm, vs cold engine on start-up.
Rgds David
 
  #5  
Old 05-13-2019, 11:06 AM
Junior Member
Join Date: Jul 2018
Posts: 22
Likes: 0
Received 1 Like on 1 Post
Default

Hi thanks for the advice.. I'm going to reset it to 10degrees before TDC...can you tell me how many degrees does a tooth on the fly wheel represent? I can't find my manual!!
 
  #6  
Old 05-13-2019, 04:12 PM
Senior Member
Join Date: Dec 2011
Location: Southern Califonia
Posts: 164
Received 49 Likes on 34 Posts
Default

If you have 132 tooth flywheel, then 3.66 teeth before TDC mark would be 10 degrees position.

Also with 10 degrees as initial setting, you may have to much max advance with "curve 4". If you get pinging between 2200-3000 rpm with hard acceleration, you will want to go to the "0" curve setting.
 

Last edited by David84XJ6; 05-14-2019 at 02:16 AM.
  #7  
Old 05-14-2019, 02:24 AM
Senior Member
Join Date: Dec 2011
Location: Southern Califonia
Posts: 164
Received 49 Likes on 34 Posts
Default

Scott

See attached listing for 123 curves. I don't have XK -120 manual, but 34 degrees at 3600 RPM was very close to XKE OEM maximum advance curve. XKE was 9:1 CR, if you have 7:1 or 8:1 CR, then 3 or 4 may be ok?

Rgds David
 
Attached Files
File Type: pdf
123.pdf (56.4 KB, 6 views)

Last edited by David84XJ6; 05-14-2019 at 02:29 AM.
  #8  
Old 05-14-2019, 06:13 AM
Junior Member
Join Date: Jul 2018
Posts: 22
Likes: 0
Received 1 Like on 1 Post
Default

That's very handy. Thanks very much
Scott
 
  #9  
Old 05-21-2019, 05:23 PM
Junior Member
Join Date: Jul 2018
Posts: 22
Likes: 0
Received 1 Like on 1 Post
Default

Hi there.
Just to report..reset the timing from scratch and I'm happy to report that the car is running perfectly!! Took it in around traffic,no problems.
Brought it in an overnight trip of approx 120miles and the car behaved perfectly
My next question is this!!
It's the only xk120 I've driven and would like to know how they are supposed to handle..I took mine down the country roads of West cork in Ireland.. I found it quite giddy over the bumps... Is this to be expected? I thought it was quite 'juddery' at high speeds..
I'm used to old stuff but not this old.. I balanced the wheels, this made a slight impression but still it's not smooth..
Any opinion would be appreciated.
Best regards,
Scott
 
The following users liked this post:
David84XJ6 (05-21-2019)
  #10  
Old 05-23-2019, 06:27 PM
Senior Member
Join Date: Dec 2011
Location: Southern Califonia
Posts: 164
Received 49 Likes on 34 Posts
Default

Scott,

Oh how I wish I were touring Ireland in an XK120. Glad to hear engine is sorted.

Is the "Giddy ...Juddering" felt in the steering column or are they a seat of the pants items?? I am more familiar with (twitchy to bone-jarring)

I maintained an XKE with similar front suspension, correct tires/ tire pressures and mostly new rubber bushings, ball joints, rebuilt steering rack, new tie rod ends, tight front bearings...needed to get all "slop" out of front end. Jack up front end from frame and wiggle wheel up & down front to back to see how tight!!! I had an old school front end alignment Tech, He dialed in Castor, Camber & Toe in + or - "0".

Notes indicate in 1950, the factory changed castor angle to positive 3 degrees from positive 5 degrees for the XK120, and the Tie-Rod bearings were changed to rubber; nothing else note worthy in suspension.

See attached article Page #3 for more specifics, from some one who knows the XK120.

http://www.guybroad.co.uk/download_c...RET-SHEETS.pdf

Rgds David
 

Last edited by David84XJ6; 05-23-2019 at 09:47 PM.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Bob Gelston
XJ XJ6 / XJ8 / XJR ( X350 & X358 )
8
09-14-2015 11:08 PM
Executivekev
XJ6 & XJ12 Series I, II & III
4
12-01-2014 10:06 AM
baywatch123
XJ XJ6 / XJ8 / XJR ( X350 & X358 )
0
10-27-2012 10:24 AM
carate
S-Type / S type R Supercharged V8 ( X200 )
3
01-09-2011 04:21 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Quick Reply: 123 ignition fitted, running v rough


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: