Yesterday I installed the Pertronix Distributor. Also did a plug change and put in the flamethrower coil. A few observations for anyone else doing this.
No matter how I "bumped" the starter, I could not get to exactly TDC. I also could not physically rotate it by pulling on the belts. I plan to make a tool to fit into the Crank pulley for the "next time".
I got to 8 BTDC, traced the #1 plug to the distributor and marked the cap. Removed the cap and noted the rotor pointing to that tower on the cap.
Removed the original distributor by pulling straight up. Because of the drive dog (as apposed to a spiral gear engagement) the distributor shaft does not rotate upon extraction.
I lined up the new units rotor to point to the the correct tower on its cap. The drive dog was in correct alignment. Dropped in the unit. Plugged the ported Vacuum line to the unit.
I followed Davids advice on removing and installing the new coil. That went flawlessly. Thanks David.
Gapped and installed the new plugs (.035"). Hooked up a timing light, crossed fingers and turned the ignition.
She fired right up! Timing was at 12 BTDC. Set the timing by slightly rotating the distributor(does not take much) to 8 BTDC.
Connected the Vac line to the distributor. Timing advanced to 25 BTDC. Reset timing to 17 BTDC.
Reset idle to 800 RPM.
Steady as a rock! Will test drive today as it was raining yesterday.

 

YIPPPEEEE !!!
As good a way of expressing it as I know of!!!

Carl

 

She fired right up! Timing was at 12 BTDC. Set the timing by slightly rotating the distributor(does not take much) to 8 BTDC.
Connected the Vac line to the distributor. Timing advanced to 25 BTDC. Reset timing to 17 BTDC.
Reset idle to 800 RPM.

Ian
Just to clarify.... The timing reset from 25 to 17 was accomplished by adjusting the idle RMP back down to 800 RPM. The 8 degrees timing you set with plugged vacuum line was to be final timing adjustment for mechanical advance, there is no adjustment for Vac advance, other than to reset reset Idle.
You must still have Rain in your area.
Rgds
David

 

So David, Do I just set at 8 BTDC with line removed and plugged and take whatever I get when it is reconnected? The original Maintenance Handbook says

"Ignition timing ....Always refer to under-bonnet label (which I do not have) --- At 800 rev/min. Distributor vacuum unit disconnected --17 degrees B.T.D.C."

 

Yes.... this is correct for the OEM Distributor only
(800 rev/min. Distributor vacuum unit disconnected -- 08 degrees B.T.D.C. is correct for Pertronix Distributor)
Between 2800 to 3500 RPM, neither distributor will have any or much vacuum advance, and both will have the same or similar max mechanical advance. (This is where you want the advance timing numbers to match)..... {XK Motor Sport Technicians (formerly part of XKs Unlimited before they sold parts business to Moss) set my OEM distributor timing at 33 degrees at 3000 RPM and did not even check idle advance timing} 1984 EFI XJ6)

Remember this distributor was sold as a replacement for earlier Jaguars with carburetors and higher compression... which were set at 700 RPM at 14 degree advance.

The 800 RPM and 17 degrees were not optimum, but did help the 1950's engine pass the California emission tests.

Rgds
David

 

Thanks David. Will follow your directions and let you know how it goes.

 

Well,
I followed Davids advice and set the timing (Vac. disconnected/plugged) at 8 BTDC. at 800 RPM idle. Reconnected Vac. and timing advanced to 12 BTDC. Reset Idle to 800 once again.

Took her out for a spin. Could be my willful imagination but moderate off the line acceleration seemed slightly improved and mid range acceleration 2000 - 3000 RPM was definitely more "spirited". No evidence of any "pinking" under hard acceleration. Basic 800 RPM idle is much improved with very little "hunting" as was there before.

Now should I play around with the timing by advancing until I get some pinking then retard unitil it goes away, or should I just leave well enough alone?

When I installed the Pertronix Distributor I also installed their High performance 40,000 volt 1.5 ohm coil and a new set of spark-plugs. The improvements could well be a combination of the three.

Thanks for everyone's input and advice.

 

Common practice, and I often use that method.

I find some hills to climb and then use light/medium throttle. You're trying to 'lug' the engine a bit. If you adjust the timing for 'no pinking on hills' you'll probably be good to go for all other driving conditions.

Cheers
DD

 

Ok Doug, Here goes!

 

Ian
Without "willful imagination" we would not keep going back to the garage for "one more improvement" to the vintage Jaguars....slightly improved ....definitely more "spirited" .... idle is much improved .... is what it's all about ... Congratulations
Rgds
David
PS: If you find the 7 degree hill that Doug recommended and increase the advance until you ping; then back-down 2 degrees and switch back to 87 octane from the 91 used when testing...you will be good.

 

David, After the test drive, returned home. Stopped the car. 5 min. later, tried to restart it. Very difficult to start, almost as if it was fighting itself to rotate. Severe engine rocking until start-up. Kind of like a reverse backfire if that makes any sense. Once started, idles very rough. Almost as if a plug or two would drop out as the rev counter would drop to 500 rpm and immediately return to 800. Will also do this while driving off the line. After 1200 rpm, all smooth.

Rechecked the timing. 28 deg. vac, connected, 22 deg. vac. disconnected. Reset the timing to 8 deg. vac. disconnected. Much improved hard starting.

Before removing the original dist. a disconnected vac. timing check showed 4 deg. BTDC. I never had a hard start condition until the unit was changed. Will try a 4 deg. setup today.

 

"Rechecked the timing. 28 deg. vac, connected, 22 deg. vac. disconnected. Reset the timing to 8 deg. vac. disconnected. Much improved hard starting."

Ian
If you had set to 8 deg vac disconnected, then did test ride with subsequent hard starting after shut down and attempted restart. Then you checked timing with vac disconnected at 22 deg , then once again set timing to 8 deg, and the hard starting was resolved?
I can believe at 22 degrees you would have bucking and hard starting ... distributor must have slipped from 8 to 22 deg. There is the pinch bolt to to tighten distributor case and the pinch bolt bracket has a bolt in a slot, that fits into the block that needs to be tightened also.

If you have a friend to help, try 3000 RPM with vac connected, you should be at 31-32 degrees. It is a little noisy and windy at 3000 RPM under the bonnet.
The smog tests are at 800 idle and 2000 RPM, so emissions are optimized for these RPMs, not performance. The 33 deg at 3000 RPM target is performance based, with some cushion to prevent knocking with the OEM distributor.
1. Vac advance for Pertronix is 4/13/10 .... OEM distributor vac advance is 4/8/8 or 4/8/5
2. Mech advance for Pertronix is 24 degrees at crank (24+ 8 = 32 max) @3200 RPM ... OEM is 20 degrees at crank (20 + 17 = 37 max) @ 4300 RPM
3. At 3000 RPM: Pertronix is 31 degrees max and the OEM is at 33 degrees max
I saw your post on unknown engine timing with Stock Distributor.... D171618 is not stock, so there are compromises
Hope you get this sorted and can get back on the road with confidence.
Rgds
David

 

Ian
Couldn't help noticing another comment from Michael on timing and unknown engine...

I will now pretend that vacuum advance doesn’t exist. It will only confuse things.[/QUOTE]
[QUOTE]

If you want to get every one going, bring up the differences between Ported Vacuum and Manifold Vacuum as the best source for the Distributor Vac advance capsule.

This is the Jaguar mid-80's solution to this debate: XJ6 S3's have both: If you look at your throttle body you will find a Vac fitting that taps into aft side of the butterfly and is for Distributor at stationary Idle (also for the smog test). The vacuum line disappears under the intake manifold and half way to the Distributor it connects to a three way timed vacuum valve ( This is a GM valve that Jaguar used to meet the emissions testing). One input to valve is from a manifold vacuum fitting and the out put goes to the distributor where you will experience either ported vacuum or manifold vacuum.

With the throttle plate closed, you are getting intake track air pressure ... no vacuum advance of distributor... With throttle cracked, the intake track will have some vacuum and if it is above the onset 4 psi of the Vacuum advance unit you will have some vacuum advance of the distributor. The mystery valve has a timed internal leak and after a few second will port manifold vacuum to the distributor ... so with light throttle, the distributor vacuum source will be manifold pressure.

This is why capping off the Vac to the distributor is important when setting idle timing.

You could have intake track pressure ( with no advance) or (manifold pressure with advance). If the valve fails you may get manifold pressure all the time which will cause a high advance signal that should not be there. Many will advise to just remove the valve and use manifold pressure all the time. This method still requires setting timing with vac capped off and reducing the idle RPM back down to spec. after reconnecting vac line.

The vac advance does it's job at light to medium throttle, and when deceleration from high RPM with throttle closed. It has little to no effect at WOT.
When it all gets sorted and is performing acceptably we should probably do a Complete Sticky
All the Best
David

 

David, Thanks for your comments. I believe that we are both getting to establishing the cause of this timing issue. Yesterday, I confirmed the following.


I won't have a Vacuum gauge until later today, so have no "readings"
a) From cold, the car fires up instantly and idles smoothly at 1100 rpm for a few minutes then drops slowly to around 800 (as it always did).
b) Did not rev the engine.
c) Disconnected/plugged vac line and Checked timing. 12 Deg. BTDC. Reconnected Vac. - remains at 12 deg. BTDC.
d) Slackened dist. and reset to 8 Deg. BTDC. Idle at 800 rpm.
e) Took her out for a test drive. Feels normal. Returned to garage.
f) Idle very rough like the plugs are dropping out. Idle 900 - 500 up ad down randomly.
g) Shut her down. Connected timing light. Very hard to get her started. Lots of bucking. Idle erratic and very rough.
h) Checked timing. 28 Deg. BTDC. Disconnected/plugged vac. (strong vac. on fingertip). Timing now at 24 Deg. BTD
i) Shut down.
j) Items (c) through (h). repeatable.

So, from a cold start and at 800 idle, Dist. vac source is very low and has almost no effect on timing (as I assume is correct). Once the engine is reved up (as on a test drive), the Dist vac source switches to very strong and remains this way. This would explain the very hard start condition as I'm trying to start an engine at 18 Deg. BTDC.

Until your post regarding this valve thingy, my thought was that the advance was sticking in the new Pertronix unit, but now I see that's not the case.

I will re plumb to ensure only a constant Manifold Vacuum source and see what happens.

I agree on the need for a "sticky",
Best regards, Ian

 

Ian

I would not discount a sticking advance mechanism. Once the 8 degree is set with vac capped off on a warm engine, this should be the case any time you check a warm engine. if you are getting 12 degrees one time and 22 degrees the next when re-checking a warm engine, then you may have a defective Distributor advance. I would call the Pertronix tech department and describe the symptoms and see if they recommend a coarse of action.

Rgds
David

 

Hard start warm with "bucking" . Clear evidence of too much advance. The dampener might have slipped and mis reads the real timing.. Too much static advance.

Or as stated, sticking mechanical. As the Peronix is new, less likely.

Double check real TDC vs that indicated on the dampener.. Off to play wit my tos outside. weather better!!!! Yipppy!

Carli

 

Ian,
Carl may have another potential candidate for drifting timing .

I have not heard of this on Jag engine.... But certainly had the problem of a slipped inner and outer dampener on my Jeep Grand Cherokee...Shop took 20 min to confirm and order new dampener... They said any Jeep with a Dodge Truck V8 Engine is suspect after 200K miles.

A rag, some solvent and two dots of white paint on inner and outer dampener across from each other, should tell the story.

Other Forum Members may have comments on this possibility.

Attached P/Ns for vac valve

Rgds
David

 

Ian

Looks like Pertronix is recommending Ported vacuum

"D171618 Installation instructions" item #8

8. For Vacuum advance distributors: Locate the vacuum hose that was previously attached to the vacuum advance canister. This hose should originate at a ported vacuum source. Some applications have vacuum advance hoses attached to a manifold vacuum source, due to the performance advance curve, we recommend that you relocate this hose to a ported vacuum source. After setting initial timing the hose will be unplugged and attached to the vacuum advance on the distributor.

Rgds
David

 

David,
Yes, that's what they recommend. I always understood "Ported" Vacuum to be taken upstream (before) the throttle plate so that it is low at closed throttle and gets progressively higher as the throttle is opened. "Manifold" Vacuum (taken from between the throttle plate and the intake valves) should be highest at idle and progressively drop as the throttle is opened.

So, on the standard Jag setup, if static timing is set at 8 deg. BTDC with the Ported vac. source disconnected and plugged, when the line is reconnected to the distributor, the timing should advance very little. Progressively opening the throttle, should give more vacuum advance supplementing the mechanical centrifugal advance as the engine speed rises.

So the purpose of the Ported/Manifold switchover valve you described must be to provide some advance (Ported sourced) at idle (for emission reasons) and as the valve switches over, progressively less advance (Manifold sourced) as engine speed increases.

If that is correct, then that valve should be bypassed to provide Ported vacuum only for the Pertronix setup..

Am I missing something? Have not had a chance to get to the car since Friday. Vacuum gauge arriving tomorrow.
Ian

 

"If that is correct, then that valve should be bypassed to provide Ported vacuum only for the Pertronix setup... So, on the standard Jag setup, if static timing is set at 8 deg. BTDC with the Ported vac. source disconnected and plugged, when the line is reconnected to the distributor, the timing should advance very little. Progressively opening the throttle, should give more vacuum advance supplementing the mechanical centrifugal advance as the engine speed rises. "

Ian
After reviewing all info, I agree, D171618 dist should be sourced to ported vacuum on XJ6 S3. Easy starting, stable idle and vacuum advance coming in slowly as throttle body plate is opened.
Look forward to test results
Rgds
David