Black smoke Series 3 2+2

Talk about the E-Type Series 3
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jagwit
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#21 Re: Black smoke Series 3 2+2

Post by jagwit » Tue Mar 17, 2020 7:03 am

Seems like we are running out of options now....

Are the two air valves (that pull the needles up) installed correctly on the left side? The two openings should be on the engine side.
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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Djerome60
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#22 Re: Black smoke Series 3 2+2

Post by Djerome60 » Tue Mar 17, 2020 2:03 pm

Philip,

yes they are in the right direction.
I have 2 spares carb therefore i'll rebuilt them... we never know.
I'll also check again all pipes especially teh one related to emission control.
BTW, do you think the check valve or gulp valves might influence my issues?
Thanks
Regards
Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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jagwit
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#23 Re: Black smoke Series 3 2+2

Post by jagwit » Tue Mar 17, 2020 3:37 pm

Djerome60 wrote:
Tue Mar 17, 2020 2:03 pm
BTW, do you think the check valve or gulp valves might influence my issues?
Jérôme

Your problem seems related to the ENTIRE LEFT bank if I understand you correctly. That means there is a very small chance that both carbs will have the same issue and I can't help but STILL suspect the choke mechanism on the left side. It is common to both carbs and can result in all 6 cylinders on that side running rich.

I was working on a V12 E recently which had a transparent "choke link pipe" and one could actually see the fuel flowing to the second carb from the first. I also found it interesting to note bubbles flowing along.... as I did not expect that.

Coming to your question about gulp valves. Even if they are open (because of the vacuum at idle) they should then result on the left side being lean, not rich. OR, block them off completely if in doubt.

Keep in mind: Engine is either getting too much fuel or too little air (or both).

If you look into the carbs on the left vs right can you SEE a difference in the amount of fuel being drawn in?
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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MLBS3V12
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#24 Re: Black smoke Series 3 2+2

Post by MLBS3V12 » Tue Mar 24, 2020 10:03 am

Cant it be an oil issue coming from the engine depress pipe ?
Le chemin sera long!...

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#25 Re: Black smoke Series 3 2+2

Post by jagwit » Tue Mar 24, 2020 10:42 am

MLBS3V12 wrote:
Tue Mar 24, 2020 10:03 am
Cant it be an oil issue coming from the engine depress pipe ?
Are you referring to the crank case ventilation pipe? Not sure which pipe you are referring to.

If so, Highly unlikely that it would affect only one bank.

If you are referring to the vacuum pipe for brakes, yes, that could affect the left bank more that right, if there is a vacuum leak somewhere.

A Series 1 I worked on had a torn servo diaphragm. That makes a huge vacuum leak.
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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#26 Re: Black smoke Series 3 2+2

Post by MLBS3V12 » Tue Mar 24, 2020 12:33 pm

Yes Philip,
I'm referring to the crank case ventilation pipe. If I'm not wrong this pipe is connected to the left bank only.
But finally I dont know what can brought to this side additionnal oil consummed into the 6 left side cylinders and neither why :scratchheadyellow:
Le chemin sera long!...

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Djerome60
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#27 Re: Black smoke Series 3 2+2

Post by Djerome60 » Thu Mar 26, 2020 8:05 am

Dear all,

many thanks again for your support and i can say now the issue is sorted.
Philipp, you were right it was the choke mecanism which was 180° wrong. It's a pitty that it took me that long as it was so obvious but i have actually disassemble the carbs includint the choke mechanism many time but the disc seemed to be well positionned. I was totally wrong!

Anyway, even if i have not tested the car on road as you can imagine i'm sure the fuel consumption will go down and there will be no more black smoke at idle.

I wish you good time whoch your beauty (your Etype i mean) while stuck at ome as most of us are currently.

Regards
Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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jagwit
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#28 Re: Black smoke Series 3 2+2

Post by jagwit » Thu Mar 26, 2020 8:23 am

Djerome60 wrote:
Thu Mar 26, 2020 8:05 am
i can say now the issue is sorted.
Excellent!! Nice to hear that your problem is finally sorted!! :bouncyyellow:

Now
1) Do you have a vacuum advance module on the distributor (not a vacuum retard)?
2) Please remind me what ignition system you have?
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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Djerome60
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#29 Re: Black smoke Series 3 2+2

Post by Djerome60 » Thu Mar 26, 2020 8:51 am

Philipp,

1) no i have a retard vaccum unit that i have disconnected.
2) i have the original ignition system

My plan moving forward is to install an advance vaccum unit on my current distributor. Does it make sense or should i go for an OPUS ignition unit? with a vaccum advance unit?

regards
jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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jagwit
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#30 Re: Black smoke Series 3 2+2

Post by jagwit » Thu Mar 26, 2020 9:19 am

Hi Jerome

Changing to a vacuum advance unit (JLM519 from SNG) should be a high priority. Just connect it to manifold vacuum and it idle - with vacuum connected, you should have around 20º advance.

If your OPUS system is working RELIABLY (even when everything is hot) then upgrading the ignition system is not urgent, BUT.... It is highly likely to fail on you.

For reliability, I would strongly recommend you upgrade the ignition system using one of the following options:
1) Get the entire ignition system from an HE XJS (distributor - already having the vacuum advance, AB14 ignition module as well as the TWO coils). This is likely to be the cheapest option and keeps your car with standard Jaguar components;
2) LUMENITION : Lumenition has an ignition module and coil combo as well as an installation kit for the OPUS distributor. This is a very modern system (I have it in my car) with complete dwell management. More costly though.
3) Pertronix Ignitor-II (NOT ignitor-I !!) I have never installed this in a V12 but others claim to have done so with success. In the OPUS dissy, it might be more of a challenge. I have installed it in my classic 6-cyl '59 Apache and it does work very well (in that truck).
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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Djerome60
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#31 Re: Black smoke Series 3 2+2

Post by Djerome60 » Thu Mar 26, 2020 10:36 am

Thanks Philip,

i have just ordered the vaccum unit from SNG and will fit this directly on my OPUC unit which is working well so far.
Regarding vaccum source i thought it should be coming from a ported one from the rear left hand side carb (to drilled) and not from the inlet manifold?
Regards
Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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jagwit
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#32 Re: Black smoke Series 3 2+2

Post by jagwit » Thu Mar 26, 2020 2:01 pm

Djerome60 wrote:
Thu Mar 26, 2020 10:36 am
Regarding vaccum source i thought it should be coming from a ported one from the rear left hand side carb (to drilled) and not from the inlet manifold?
There is a huge debate about that. The only benefit I can see of using ported vacuum, is that it warms the engine up quicker on a cold start. Which is technically correct. Why? Because ported vacuum makes the engine idle INEFFICIENTLY ( meaning NOT efficient). It is this increased INefficiency that results in a quicker warm-up.

But....

Now, once it has warmed up, EVERY time the car idles and ALL the time it idles, it is doing so INefficiently. Meaning, the engine is consuming more fuel during idle and generating more heat during idle. With manifold vacuum is will use less fuel and hence generate less heat because it is idling MORE EFFICIENT. My own car is configured like this.

BTW: Is that port you referred to, REALLY ported vacuum? I'm not 100% sure it is.
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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#33 Re: Black smoke Series 3 2+2

Post by Djerome60 » Fri Mar 27, 2020 12:14 pm

David,

the ported vaccum i was refering to is the vaccum port that must be drilled on the rear left hand side carburator.
So if i understand correctly what you suggest:
- I fit the advance vaccum unit JLM519 on my current ditributor unit to retplace the retard unit currenty fitted
- I connect the vaccum unit to the inet manifold
- I adjust the timing to be at idle 750 RPM at 20° TBC VS 12° today

Am i right?
I always thought the suction of the inlet manifold was too high and will correct completely the advance at low/Mid revs while sourcing firm the carb will be more progressive up to the high engine revs.
I understand also that there are also a lot of discussions around this ans i'll therefore follow your advices.

Thansk Again;
regards
Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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MarekH
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#34 Re: Black smoke Series 3 2+2

Post by MarekH » Fri Mar 27, 2020 12:31 pm

Ultimately, the vacuum comes from the same place, so ported vacuum is manifold vacuum when the throttle is opened any significant amount. At very low throttle openings, ported vacuum partially throws away the vacuum signal and at closed throttle (e.g. when stopped at the traffic lights idling), it completely throws away the vacuum signal.

If connected to an advance capsule, this simply means you engine runs more retarded when the throttle is shut (or nearly shut) and so generates more heat at minimal throttle openings. You'll be needlessly generating engine heat when stationary (i.e. no airflow and minimal waterflow) just when you need your cooling system the most. As Philip points out, the engine runs less efficiently with less advance and so you are throwing money and performance down the drain.

How much are you throwing away?

Lets look at a few graphs....

The first records how open the throttle is so you can get a handle on how far open the throttle is at different revs and different engine loads (MAP=0 is zero load (e.g. overrun) and MAP=100 is heavy load (steep uphill, pedal thumped hard to the metal...))
tps for ported vac graph.png
tps for ported vac graph.png (57.73 KiB) Viewed 1139 times
This tells us that the throttle is roughly half open at full load and medium revs; it is about a third open at heavy load and low revs; it is shut at idle (blue spot); it is shut at low revs; it generally spends most time about 20% open to 35% open.

The second graph records the pressure at the ported vacuum port. 100 = atmospheric pressure, so there is no vacuum signal if the graph reads 100 and there is maximum vacuum signal if the graph reads 0. Manifold vacuum is the left hand axis, so what you are looking for is how different the numbers in the boxes are from the number on the y axis.
ported vac graph.png
ported vac graph.png (61.46 KiB) Viewed 1139 times
So at high engine loads, when the throttle is most certainly open, the ported vacuum equals manifold vacuum - all the numbers in the top row are between 92 and 100, so ported vacuum does nothing for you - it IS manifold vacuum anyway; if you draw a diagonal line from top left to bottom right, anywhere above that line ported vacuum equals manifold vacuum, so again, it does nothing for you. Below that diagonal line, the lower the revs and the lighter the load, the throttle plate is more closed on average and the ported vacuum signal returned is being thrown away and the engine is going to run more more retarded, generating more heat. For example, at 1700rpm with the engine 50% loaded, the vacuum signal is on average 100-73 = 27, whereas with manifold vacuum it would be 100-49 = 51, so you are throwing away half of your vacuum signal for advance when cruising.

Essentially having some vacuum advance is better than none which is the default etype v12 position, and everyone who fits ported vacuum waxes lyrical about how much better it is than the vacuum retard capsule that was fitted. What Philip keeps trying to remind you is that having full vacuum advance is even better. It is better in each cell by how much (100-MAP) is greater than the (100- number in the table) on the same row as the MAP figure on the left hand side.

There is no case where you get more vacuum advance with ported vacuum than you get with just straight manifold vacuum (MAP) so you are simply running more retarded than you need to, all other things being equal. Since you spend a significant amount at part throttle, you are throwing away much of your performance a significant amount of the time. When you put your foot down, ported vacuum equals manifold vacuum so being "ported" is nothing special - it's just regular normal manifold vacuum advance.

kind regards
Marek

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#35 Re: Black smoke Series 3 2+2

Post by jagwit » Fri Mar 27, 2020 2:34 pm

What Marek was kindly saying, in many words were: "You can safely connect to manifold vacuum". :bigrin:
Djerome60 wrote:
Fri Mar 27, 2020 12:14 pm
the ported vaccum i was refering to is the vaccum port that must be drilled on the rear left hand side carburator.
There is THAT word again. There is no such thing as "must". If you REALLY want ported vacuum, then yes, the carbs require that a hole be drilled. I will never take THAT chance....
Djerome60 wrote:
Fri Mar 27, 2020 12:14 pm
So if i understand correctly what you suggest:
- I fit the advance vaccum unit JLM519 on my current ditributor unit to retplace the retard unit currenty fitted
- I connect the vaccum unit to the inet manifold
- I adjust the timing to be at idle 750 RPM at 20° TBC VS 12° today
Correct - if you live near sea level. I live at 1400 meters above sea level, so I set mine to 24°to compensate a little for altitude.

Don't be surprised if you find the engine is idling higher than before having done the above. Why is it idling faster? It is running more efficient, hence more power is being produced. So you may have to tune the carbs to reduce the idle speed back to 750 - 850rpm.
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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Djerome60
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#36 Re: Black smoke Series 3 2+2

Post by Djerome60 » Fri Mar 27, 2020 2:48 pm

Marek, Philip,

Pretty impressive analysis. Forgive my naive questions, doing mecanic is just and hobby and i keep learling every day.
Many thanks i'll follow your advice and will report without any doubt my entore satisfaction once done.
have a great week end and take care.
Best regards

Jérôme
Regards
Jérôme

E type Series 3 - 2+2 1972
Peugeot 304 Cab 1971

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MarekH
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#37 Re: Black smoke Series 3 2+2

Post by MarekH » Fri Mar 27, 2020 3:16 pm

Actually, that's not what I said, but it is almost certainly true. You don't want to over advance the engine no matter where you connect your vacuum to.

At very low engine loads, it is generally safer to see higher advance than the same amount of advance at higher engine loads.

The amount of advance is the same with either vacuum connection at medium to high engine loads. Manifold vacuum gives more advance at medium to low engine load than ported vacuum does.

If it idles at a higher speed due to the extra advance, then you can adjust the throttle plates to be a bit more closed and/or drop the static timing a bit.

kind regards
Marek

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madjack4
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#38 Re: Black smoke Series 3 2+2

Post by madjack4 » Fri Mar 27, 2020 4:21 pm

Hi all ive posted many times on this subject of ported v full manifold pressure i am going to do a comparison on my s3 can i ask these people with advance unit with full manifold pressure what do u set the timing at and how do u set it with vac removed or connected i set mine at 12deg at 800rpm with strobe with my ported vac disconnected if someone can tell me what to set it with full vac as i run SU carbs and have both forms of vac i will do a 100 mile roadtest with ported vac and my setting and a 100 mile roadtest with your settings on the same route and compare performance and fuel economy and i will report back that sorts it out once and for all :swerve: i hope i get an improvement with full vac we will see when the driving ban is lifted please let me know asap the full vac settings as i will set my car up to that while im bored to death confined to home

Thanks very much in advance

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#39 Re: Black smoke Series 3 2+2

Post by jagwit » Fri Mar 27, 2020 5:04 pm

madjack4 wrote:
Fri Mar 27, 2020 4:21 pm
Hi all ive posted many times on this subject of ported v full manifold pressure i am going to do a comparison on my s3 can i ask these people with advance unit with full manifold pressure what do u set the timing at and how do u set it with vac removed or connected i set mine at 12deg at 800rpm with strobe with my ported vac disconnected if someone can tell me what to set it with full vac as i run SU carbs and have both forms of vac i will do a 100 mile roadtest with ported vac and my setting and a 100 mile roadtest with your settings on the same route and compare performance and fuel economy and i will report back that sorts it out once and for all :swerve: i hope i get an improvement with full vac we will see when the driving ban is lifted please let me know asap the full vac settings as i will set my car up to that while im bored to death confined to home

Thanks very much in advance
If you have a vacuum advance unit and use manifold vacuum, you can set the timing as follows:
1) Leave the vacuum connected and set it to 22°; OR
2) Disconnect the vacuum and set timing to 12° (reconnecting the vacuum should have the timing back at 22° because the vacuum advance unit should add about 10° with manifold vacuum**)

If you have ported vacuum connection on the carb you can set the timing as follows:
1) leave the vacuum line connected and set the timing to 12°; or
2) disconnect the vacuum line and set the timing to 12°.
(I have not made an error above. Ported vacuum should present NO VACUUM when idling. If it does, your "ported vacuum" has not been drilled correctly because the hole then came out on the manifold side of the butterfly.)

** I have recently seen an adjustable vacuum advance unit on a V12 I had been asked to tune. I was adjusted to add maximum advance which was WAAAYYY too much. Even when I adjusted it to is minimum, it was still advancing too much. So, I am suggesting you CHECK HOW MUCH ADVANCE the vacuum advance is adding!!

MJ4, please do that test as you will thoroughly enjoy the drive!! :bigrin: However, I doubt your test will prove anything (once and for all), since as Marek showed, there MIGHT be a small difference at very light throttle - BUT IS THIS MEASUREABLE?? The MAJOR difference between ported and manifold vacuum comes into play AT and during IDLE .

Therefore a more accurate test would be to have the SAME engine idle for, say, 1 hour with manifold vacuum and then with "ported" (which would be the same as simply disconnecting the vacuum line from the vacuum advance unit). In both cases the engine should be set to idle at the same idle speed. For each 1 hour test, the fuel consumed should be accurately measured as well as the "amount of heat generated" (this would be a bit more of an engineering challenge to measure). I would also recommend the flow rate of the coolant be measured as I expect the thermostats will be wider open with ported vacuum (thus higher coolant flow rate). I also expect the fans will be on for longer ( a higher duty cycle) than with manifold vacuum.
Best Regards
Philip
Jag: 72 E-type V12, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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#40 Re: Black smoke Series 3 2+2

Post by madjack4 » Fri Mar 27, 2020 8:57 pm

Hi so basic timing is the same so i will just move the vac pipe so i have full vac i guess i will have to adjust the tickover as it will speed up due to extra advance n lets see what happens to be honest i bought my advance unit off british vacuum advance co in usa i spoke to him at great length and he told me over the years he has fitted hundreds of advance units and he found the best way forward was ported vacuum my car returns 26mpg on a run and 21mpg local so i will do a test run involving both i changed to vac advance at same time as fitting SU carbs so never had a comparison vac retard to vac advance it runs standard 4 speed with a 2.88 dif i find that set up perfect can still go round a roundabout in top gear and acceleration through gears is excellent having said that i fully rebuilt the motor 12 months ago carnt wait now to do a test

Regards

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