123 Tune which Coil?

Talk about the E-Type Series 1
User avatar

Heuer
Administrator
Posts: 12880
Joined: Sat Mar 01, 2008 5:29 pm
Location: Nottinghamshire
Great Britain

#41 Re: 123 Tune which Coil?

Post by Heuer » Mon Jul 22, 2019 4:24 pm

I have that book somewhere but I will need to find it!

In the meantime have you checked the Mehajolt support thread and looked at the various maps and timing there - could give you a clue. This is what a standard engine looks like and how to read the map:

This is the 4.2 Megajolt map which broadly follows the standard Jaguar vacuum distributor:

Image
Image

More here: http://forum.etypeuk.com/viewtopic.php?f=9&t=437
David Jones
S1 OTS OSB; S1 FHC ODB

Add your E-Type to our World Map: viewtopic.php?f=1&t=1810

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
andrewh
Posts: 2361
Joined: Fri Dec 21, 2007 8:31 am
Location: kent
Great Britain

#42 Re: 123 Tune which Coil?

Post by andrewh » Mon Jul 22, 2019 4:38 pm

Thanks David. Will check that out with my glass of wine later. I have now bought the book on line off eBay. Good idea on the megajolt website. 👍
1962 3.8 Series One FHC

http://etype860897.blogspot.com/

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Turnip
Posts: 87
Joined: Sat Oct 25, 2014 9:57 am
Location: Wiltshire
Great Britain

#43 Re: 123 Tune which Coil?

Post by Turnip » Mon Jul 22, 2019 8:40 pm

andrewh wrote:
Mon Jul 22, 2019 3:52 pm
OK , well I have now timed the 123 statically to TDC and will put in the curve on the APP. I am assuming that we start at 500 rpm 10 degree advance and go from there. What I am unsure of is what the vacuum advance should be in inches of Mercury. I should have listened more in Physics :bigrin: The 123 not so helpfully is graduated in kilopascals ( ?)
I had heard that curve 7 on the standard 123 works very well, does anyone have the profile for that, at least before I go off to the rolling road. Sorry this thread has developed into a 123 Distributor thread but I am sure it will be of use to others. Anybody got the book on power tuning XK engines? That may have some useful stuff in it, but I have not been able to purchase a copy.
You're not going to be far wrong if you start with the factory's maximum values for the distributor.
Those values are (in crank terms, not distributor ones):
rpm adv
1050 3
1300 8
1600 14
2500 17
3600 21
4600 21
Your preferred static value needs to be added, as you've initialised the 123 at tdc (so 10 in your case).

They worked alright for me, on a pretty standard 4.2. We (or rather, the rolling road operator) found that you can easily go to maximum advance at 3000rpm. Could probably be earlier than that if you want to experiment.
We also observed that maximum hp started to drop off a bit if we had 32 or more (21+10) degrees of advance. But that is probably just my engine.

As for the vacuum, I don't have the figure I used to hand. But again they are a straightforward copy of the maximum Lucas values.

Simon
1965 Series 1 4.2 FHC

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

abowie
Posts: 2513
Joined: Wed Sep 07, 2011 9:15 pm
Location: Australia
Contact:
Australia

#44 Re: 123 Tune which Coil?

Post by abowie » Tue Jul 23, 2019 2:19 am

andrewh wrote:
Mon Jul 22, 2019 3:52 pm

What I am unsure of is what the vacuum advance should be in inches of Mercury.
1ATM =760mmHg.

101kPa = 760/25.4 inHg

1kPa = 0.295 inHg
Andrew.
881824, 1E21538. 889457..oops
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
andrewh
Posts: 2361
Joined: Fri Dec 21, 2007 8:31 am
Location: kent
Great Britain

#45 Re: 123 Tune which Coil?

Post by andrewh » Fri Jul 26, 2019 6:29 am

Thanks Andrew. I eventually found a converter on the web. Have yet to take the car out for a drive S it’s been so hot here. Something you must be used to down under.
1962 3.8 Series One FHC

http://etype860897.blogspot.com/

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

abowie
Posts: 2513
Joined: Wed Sep 07, 2011 9:15 pm
Location: Australia
Contact:
Australia

#46 Re: 123 Tune which Coil?

Post by abowie » Fri Jul 26, 2019 8:19 am

Heuer wrote:
Mon Jul 22, 2019 4:24 pm

Mehajolt
From Mehico?
Andrew.
881824, 1E21538. 889457..oops
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

abowie
Posts: 2513
Joined: Wed Sep 07, 2011 9:15 pm
Location: Australia
Contact:
Australia

#47 Re: 123 Tune which Coil?

Post by abowie » Fri Jul 26, 2019 8:21 am

andrewh wrote:
Fri Jul 26, 2019 6:29 am
Thanks Andrew. I eventually found a converter on the web. Have yet to take the car out for a drive S it’s been so hot here. Something you must be used to down under.
Over 40*C is shit in anyone's language. Adelaide got to 47*C once last year. It was awful.

Here it is mid winter and it's been like summer in Newcastle for the last month; 13*C and drizzling.

I'm an anaesthetist and we use mmHg and cmH20 for a lot of our pressure readings, so conversions are my bread and butter.
Andrew.
881824, 1E21538. 889457..oops
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
andrewh
Posts: 2361
Joined: Fri Dec 21, 2007 8:31 am
Location: kent
Great Britain

#48 Re: 123 Tune which Coil?

Post by andrewh » Fri Jul 26, 2019 9:11 am

Excellent, glad the weather is not too hot there. Its eased off here in Kent now , back to 20 something I guess. Just trying to fit a new distributor to the XJS and then it will be back to the E type for finally sorting. Good to know we have an anaesthetist here....you never know when I may need advise!!! thx again.
1962 3.8 Series One FHC

http://etype860897.blogspot.com/

Link:
BBcode:
HTML:
Hide post links
Show post links


Grant
Posts: 114
Joined: Sun Jan 15, 2017 12:45 pm
Location: East Preston, W sussex
Great Britain

#49 Re: 123 Tune which Coil?

Post by Grant » Fri Oct 04, 2019 4:52 pm

Hi ALL

I was just wondering did anyone ever figure out the way to fit one of the 123 to their satisfaction?
I have a Bluetooth one which I’m too scared to start the conversion:-/.
I am really a beginner and although I have changed brakes and clutch cylinders brakes etc I have never done the timing.
Is is just better to leave alone and get an expert ?
Would someone who is used to doing timing on old cars find it easy enough ?
Does anyone know if there is an idiot guide on the internet yet ?
I have seen the Dutch guy with the BMW.but it did not really leave me feeling I know how to do it .

This is all part of my strombergs to Su carb conversion, so as I know I need to change the distributor for the su’s I thought this would be the simplest option.
To change one thing at a time,
so the question is when this is set up ,is it the same settings for the Su ‘s?
Oh and is it necessary to change the coil ?and have read all this and there does not seem to be a definitive answer but I’m just happy to copy someone who has done it already successfully:-)


Thank you in advance for any pointers

Grant
Series 2 OTS LHD

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Jaglex
Posts: 81
Joined: Wed Sep 25, 2013 2:42 pm
Location: Hamburg
Germany

#50 Re: 123 Tune which Coil?

Post by Jaglex » Fri Oct 04, 2019 5:15 pm

Just following the instructions I found it pretty easy and straightforward.
Since then I'm happy with the 1-2-3 and that is since years.
You'll manage to do it.
Have fun!
Alex
Ser. 1.5 DHC LHD

Link:
BBcode:
HTML:
Hide post links
Show post links


Grant
Posts: 114
Joined: Sun Jan 15, 2017 12:45 pm
Location: East Preston, W sussex
Great Britain

#51 Re: 123 Tune which Coil?

Post by Grant » Sat Oct 05, 2019 1:59 pm

Thanks Alex ,
I’m just getting up the courage , !
Series 2 OTS LHD

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic