In reply to a message from Richard L. sent Mon 22 Mar 2010:
Interesting document, in retrospect it looks like the chapter on
blood letting in a 13th century medical book.
Jeff, did you ever post which model number distributor you have and
is it clear that you were referring to the S 1 1/2 and not the S2
as in the title of this thread ?
Is the conclusion this was a failed experiment ? Did these cars
comes back with holed pistons like the 2.8’s ? I have seen similar
oddities in other makes with early emission cars, but always with a
1 or 2 point compression drop. I would think that with todays’
fuel you would have to back out at least 6 or 8 degrees, which
means recurving or a different distributor to me.
Paul–
The original message included these comments:
Which is how I’ve always set timing.–
The original message included these comments:
For all those reasons, road testing to get the maximum
advance set to just the edge of pinging under a good
load (WOT, uphill) yields the best setting compromise.
–
Paul Wigton, steward to a '60 DKW 1000 SP, Tweety, '63 FHC!
Keenesburg, CO, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from PS sent Tue 23 Mar 2010:
Paul,
I was referring to the later S2 with the 41322A dizzy.
The Technical Bulletin clarifies a lot. As has been mentioned in
these posts it’s best to set the timing based on road tests but
it’s nice to know where you’re starting from!
Now I’ve discovered my version of the S2 set up has a very slow
advance curve I’m wondering if a change to a non standard needle
and jet would be worthwhile, to avoid the timing and hence
performance being limitded due to the very weak mixture. Similarly,
do the camshafts specific to this engine limit things?
Best regards,–
The original message included these comments:
Jeff, did you ever post which model number distributor you have and
–
Jeff R
Camberley, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Jeff R sent Tue 23 Mar 2010:
Jeff,
So at the beginning of this thread you thought your new distributor
was 8 degrees retarded, but it is really 7 degree more advanced ?
Do I have that right ? And your engine is pinging because you have
changed the max advance from 27 to 34 with a new distributor ?
The cam change was more about tappet noise than performance. You
must use the later clearances if you have the two bolt flange with
the groove or the four bolt cams.
Paul–
The original message included these comments:
Paul,
I was referring to the later S2 with the 41322A dizzy.
The Technical Bulletin clarifies a lot. As has been mentioned in
these posts it’s best to set the timing based on road tests but
it’s nice to know where you’re starting from!
Now I’ve discovered my version of the S2 set up has a very slow
In reply to a message from Jeff R sent Tue 23 Mar 2010:
Jeff,
My advice is to make the best of what you have. Use the proper
heat range spark plug (I like NGK 6’s), the highest octane fuel you
can find, and do everything you can to lower the intake air temp
and keep the coolant temp reasonable. Having the under load
mixture (AFR) tested on a rolling road or with a wide band O2
sensor will tell you if a richer needle is a good idea.
Paul–
The original message included these comments:
Paul,
I think you’ve got that just about right!
In my defence I have to say that 34 degrees at 3000 or over is the
lowest setting on the JAG 123.
Any suggestions?
In reply to a message from Jeff R sent Tue 23 Mar 2010:
Hi Jeff,
No problem - I have a flat spot on my head from trying to
establish the spec of a Lucas dizzy. It seemed every time I
measured it, I got a different answer.
There is a spec with 4 different curves on the 123GB that is
max 27 degrees at different rpm 4200, 3600, 3000 and 2400
and has 10 static. 123 may reprogram your dizzy for you if
you decide that is the way to go.
On the real plus side, your question has added substantially
to the knowledge base on the forum.
Regards
Keith–
The original message included these comments:
You’re right. Now I’ve learned my max advance on the Lucas is 27
I’ll need to get back to TDC to bring the JAG123 curves in line.
At least I’ve learned a lot along the way!
–
Keith Bertenshaw
Rockaway, NJ, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from KeithB sent Sat 20 Mar 2010:
Hi Richard,
Apologies for not getting back to you sooner but thank you for
taking the trouble to send the Technical Bulletin. As far as I’m
concerned this has been the ‘missing link’. With all the assistance
I’ve received over the past few days I feel I have a much better
understanding of the problem.
My aim has been to get the engine running smoothly and safely. The
power is more than adequate both in accelertion and the cruise.
Besides - if you go too fast you miss the public staring in awe!
regards,–
Jeff R
Camberley, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from PS sent Tue 23 Mar 2010:
Paul - you asked if the mechanical only (no vac)/41 deg diz 41207
was a failed experiment. I think so by my experience. I strobed the
curve by rpm and found it to be right to spec@rpm. But my car never
ran well till I put a mallory in. I set it at 11 BTDC and havent
touched it in 4-5 yrs. It ran so well I never bothered to strobe
the Mallory to compare the curves. Time to drive!
I still would like to know what in that Lucas dist kept the car
from performing. It had no bottom end snap. No urgency to rev.
Also I think I agree with you about NGK 6’s. I’ve been running 5’s.
Scary white. Still, no problems in years…
FWIW
Dave
Dave–
The original message included these comments:
Is the conclusion this was a failed experiment ? Did these cars
comes back with holed pistons like the 2.8’s ? I have seen similar
oddities in other makes with early emission cars, but always with a
1 or 2 point compression drop. I would think that with todays’
fuel you would have to back out at least 6 or 8 degrees, which
means recurving or a different distributor to me.
–
1969 BRG OTS
Skaneateles, NY, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from David Ahlers sent Tue 23 Mar 2010:
‘‘I set it at 11 BTDC and havent touched it in 4-5 yrs. It ran so
well I never bothered to strobe the Mallory to compare the curves.
Time to drive!’’
Yea, BUDDY! The Mallory was the single best upgrade I made to
Tweety; Set it-n-fergot it!–
Paul Wigton, steward to a '60 DKW 1000 SP, Tweety, '63 FHC!
Keenesburg, CO, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
I’m running a six tower XJ-40 coil and its just way to sweet of a deal.
Wonder how many parts are in a dizzy, wonder how many of those parts can go
south?
Mike Goodwin & KoolKat
’ 68 OTS E Type W/HT & SUs / EDIS @ 38* advance
Phoenix, AZ USA www.beataz.com----- Original Message -----
From: “L.Lynn” lgardner28@cableone.net
To: e-type@jag-lovers.org
Sent: Wednesday, March 24, 2010 5:56 PM
Subject: Re: [E-Type] 1970 S2 Avance Curve
In reply to a message from Wiggles sent Wed 24 Mar 2010:
Mallory, smallory, I love my 85 XJ6 dizzy and it’s authentic
Jaguar
Cheers,
Lynn
The original message included these comments:
Yea, BUDDY! The Mallory was the single best upgrade I made to
Tweety; Set it-n-fergot it!
–
Lynn G.
68/85 ots, 73 2+2, Boise, Id., United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from David Ahlers sent Tue 23 Mar 2010:
Dave,
White is the new tan. I like 6’s if the compression is over 175
psi, 5’s are better for worn, lower cpmpression engines that burn a
little oil.
My guess would be anyone with that distributor would be retarding
it to the point that the curve would be all wrong.
Paul–
The original message included these comments:
Paul - you asked if the mechanical only (no vac)/41 deg diz 41207
was a failed experiment. I think so by my experience. I strobed the
curve by rpm and found it to be right to spec@rpm. But my car never
ran well till I put a mallory in. I set it at 11 BTDC and havent
touched it in 4-5 yrs. It ran so well I never bothered to strobe
the Mallory to compare the curves. Time to drive!
I still would like to know what in that Lucas dist kept the car
from performing. It had no bottom end snap. No urgency to rev.
Also I think I agree with you about NGK 6’s. I’ve been running 5’s.
Scary white. Still, no problems in years…
FWIW
