Running Temperature etc

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jagwit
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#21 Re: Running Temperature etc

Post by jagwit » Thu Jul 26, 2018 7:15 am

colin gray wrote:
Wed Jul 25, 2018 9:46 pm
So most Thermostats are rated at 82 degrees and I have not seen any for sale at a lower temperature so far
74degC thermosat is available from SNG, C28067.

Regardless from what temp rating you get, please do measure the distance they SHOULD open on your car and then measure the distance the thermostats actually open. Latter must be at least 1mm more.

I have learnt with these classics to question almost everything I encounter, by asking WHY is it like this. So very often the answer lies with "emissions". The conclusion being, it was better for meeting the emissions regs applying at that time, but it was not better for the engine (or your pocket). The vacuum retard diaphragm on the S3 is perhaps the best example.

So the question I'm asking in this instance: "Is 74degC better for the engine than 82degC or 88degC?" I believe they all have merits....
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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colin gray
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#22 Re: Running Temperature etc

Post by colin gray » Thu Jul 26, 2018 8:16 am

jagwit wrote:
Thu Jul 26, 2018 7:15 am
colin gray wrote:
Wed Jul 25, 2018 9:46 pm
So most Thermostats are rated at 82 degrees and I have not seen any for sale at a lower temperature so far
74degC thermosat is available from SNG, C28067.

Regardless from what temp rating you get, please do measure the distance they SHOULD open on your car and then measure the distance the thermostats actually open. Latter must be at least 1mm more.

I have learnt with these classics to question almost everything I encounter, by asking WHY is it like this. So very often the answer lies with "emissions". The conclusion being, it was better for meeting the emissions regs applying at that time, but it was not better for the engine (or your pocket). The vacuum retard diaphragm on the S3 is perhaps the best example.

So the question I'm asking in this instance: "Is 74degC better for the engine than 82degC or 88degC?" I believe they all have merits....
Thanks Philip, Yes really which is best would be a better way to put it. I will measure the housing and the stats as you suggest, I have just got a couple of 82 degree ones from Manners but will see what is in my car when I take it down. If they are 82 and opening at 82 then I may well get the SNG ones at 74 to try instead of fitting the same but new as I would like a cooler engine. A good bit of all that heat certainly finds its way to the cabin. I do have the modified distributor and ignition kit fitted from SNG as the Opus did the usual of giving up but I do not know if the vacuum is the same setting as original or not.
Regards
Colin

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jagwit
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#23 Re: Running Temperature etc

Post by jagwit » Thu Jul 26, 2018 8:39 am

colin gray wrote:
Thu Jul 26, 2018 8:16 am
I do have the modified distributor and ignition kit fitted from SNG as the Opus did the usual of giving up but I do not know if the vacuum is the same setting as original or not.
Regards
Colin
In that case you would still have the unfortunate vacuum retard module (SNG sticks to originality understandably) which is costing you at least 20% in open road fuel economy and also a good deal in "unresponsiveness / lethargy" in town.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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#24 Re: Running Temperature etc

Post by jagwit » Thu Jul 26, 2018 8:53 am

jagwit wrote:
Thu Jul 26, 2018 8:39 am
In that case you would still have the unfortunate vacuum retard module (SNG sticks to originality understandably) which is costing you at least 20% in open road fuel economy and also a good deal in "unresponsiveness / lethargy" in town.
The vacuum retard module is ALSO costing you a great deal in engine efficiency - basically at all times except when full throttle (when there is no vacuum to retard the timing). A less efficient engine produces more heat... more strain on the cooling system, the radiator fans, the alternator.

My ex-Daimler Double 6 has an elaborate system to DELIBERATELY make the engine inefficient on a cold start, which produces more heat, which makes the engine warm up quicker, BUT this system switches itself off when the engine reaches operating temp and then normal vacuum advance (and engine efficiency) applies.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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Barry
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#25 Re: Running Temperature etc

Post by Barry » Fri Jul 27, 2018 10:28 am

My 6.0 litre V12 OTS has occasionally hit the L in volume traffic in temperatures of 28 plus. Fan kicks in and gradually reduces. Engine is fine and dandy as they say across the pond!
Best Barry

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#26 Re: Running Temperature etc

Post by colin gray » Fri Jul 27, 2018 2:59 pm

jagwit wrote:
Thu Jul 26, 2018 8:53 am
jagwit wrote:
Thu Jul 26, 2018 8:39 am
In that case you would still have the unfortunate vacuum retard module (SNG sticks to originality understandably) which is costing you at least 20% in open road fuel economy and also a good deal in "unresponsiveness / lethargy" in town.

Well I opened a can of worms here then! So am I better off plugging up the vacuum retard module and running no distributor vacuum retard or can I get it changed to better settings? I am hoping to re set the ignition timing and generally tune her up. As you mention it doesn't feel like the most responsive thing out there and I sure would like to find the hiding horses. I though that might be due to driving a 5.0s F type now and again which is bit of a beast! :twisted: :twisted: although the horses that were there may have just laid down an died :?:
Last edited by colin gray on Sat Jul 28, 2018 8:33 am, edited 2 times in total.

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#27 Re: Running Temperature etc

Post by mgcjag » Fri Jul 27, 2018 3:14 pm

Hi Colin....you dont have to quote the whole of the post your replying to....you can edit down to the relevent sentance....it does use up valuable server space.....thanks.... Steve
Steve
1969 S2 2+2 & Building a C type replica

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#28 Re: Running Temperature etc

Post by jagwit » Fri Jul 27, 2018 6:45 pm

colin gray wrote:
Fri Jul 27, 2018 2:59 pm
[quote=jagwit So am I better off plugging up the vacuum retard module and running no distributor vacuum retard or can I get it changed to better settings?
You are better off removing the vacuum pipe off the vacuum retard module and plugging it, either at the dissy end or at source.

You will be even better off replacing the retard module with an advance module (also available from SNG)

And now we come to another case of worms.... Where to source vacuum from for this advance module....

I maintain that the advance diaphragm can be supplied directly with manifold vacuum(my own car runs happily like this) , but others can not accept that its ok, and will insist that you HAVE to supply "ported vacuum", which requires a carb to be drilled to implement ported vacuum. If you want to understand better, I'll explain both views via pm. Neither method will break your engine, (unless the drilling of the carb is botched), so its rather academic.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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42south
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#29 Re: Running Temperature etc

Post by 42south » Fri Jul 27, 2018 9:44 pm

Hi Colin,
I do agree with Philip regarding the vacuum retard module on your distributor. Just disconnect it and plug the port on it and the manifold. Your car will run just fine without it.

For some unbiased advice on suitable vacuum advance modules take a look through this website.
www.britishvacuumunit.com
Rob the owner is very helpful and there is info on here about "ported vacuum" and also a complete listing of many jaguars and the original fitted distributor with the vacuum unit settings.
I used Rob and was very happy with his knowledge and service.
For Interest he recommended using the vacuum advance unit 54405202 which is the one listed for the 1982-89 Jaguar XJS
His other recommendation was to set the static timing to 12deg BTDC which he claims helps with cooling.
I did both of these recommendatios to my car and it runs nicely, no pinking, excellent acceleration.

You have unleashed the tiger with talk of ported or not vacuum source. There is much discussion on the board on this, try a search. For the record I have been persuaded that ported vacuum is the best answer, Jaguar thought so too.

Cheers
Mark
Mark Brown
1971 S3 Etype
Son: when I grow up, I want to be a pilot
Dad: You’ll have to choose.

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#30 Re: Running Temperature etc

Post by jagwit » Sat Jul 28, 2018 6:26 am

42south wrote:
Fri Jul 27, 2018 9:44 pm
You have unleashed the tiger with talk of ported or not vacuum source.
It seems I was mistaken. Its not a can of worms, it appears to be a tiger! :bigrin:

I don't understand why though. It seems to me that I'm the only individual on earth who holds the view that manifold vacuum is good for the engine (and the owner) - at idle. So, I must be wrong, right...?

Colin, this thread of yours is about "running temperature", not about ported vacuum or otherwise. Therefore I feel compelled to present the best solution from a cooling perspective - NOT based on :
- "this is how its always been done"; or
- "Jaguar thought it was good, so therefore, it must be" (the same "Jaguar" who also thought the vacuum retard ignition solution on the S3 was "good"...). And it WAS!! "Good" that it is.... (but for Jaguar, not for the car, not for the owner).

As such I maintain that manifold pressure sourced vacuum in conjunction with a vacuum advance diaphragm, WILL yield the lowest possible demand on the cooling system - at idle, and when driving at partial throttle. Nobody, NOBODY, will be able to PROVE me wrong in this on an engineering level.

I do not contest that ported vacuum has merits (3 to be exact), but I do contest its merit as the ONLY method of supplying vacuum to the vacuum advance diaphragm when another far less complicated, less risky, less costly, more beneficial solution is on hand. Fear not, this is the last I will say on this matter in this thread.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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#31 Re: Running Temperature etc

Post by colin gray » Sat Jul 28, 2018 7:48 am

jagwit wrote:
Sat Jul 28, 2018 6:26 am
42south wrote:
Fri Jul 27, 2018 9:44 pm
You have unleashed the tiger with talk of ported or not vacuum source.
It seems I was mistaken. Its not a can of worms, it appears to be a tiger! :bigrin:



Well as things go there is a beast known as a Tiger Worm so maybe that is where we are at right now.

I have seen the some info on the ported non ported vacuum and understand how having ported gives zero advance at tick over and non ported does give vacuum at tick over.
As you said Phillip the thread is on running temperatures and I guess we have arrived here as a result of somewhere it being said that the vacuum retard unit produces higher temperatures and is not necessarily good for the engine only for Jaguar and the emissions guys (emissions no problem here in the UK)
Well we are here now and I will keep all my porting non porting searches elsewhere and I am grateful for all the advice and knowledge given here even that that is at odds with each other as I can take my pick on which way to go.
I summary I have a wedding to have the car at and will not be interfering until after that so it will be mid August at the earliest.
I plan to flush the cooling system through thoroughly, test the current thermostats and then decide which temperature rated ones to replace them with. Refill with a new 50/50 bluecol mix and then fit a new vacuum advance unit with the vacuum take off to be decided closer to the time. Naturally I will reset the timing to 12 degrees at idle zero vacuum as the Jaguar book recommends, sync the carbs and set the needle level. I will report back on any change in running temperature and weather the etc hear (pulsing lights has been cured) I will be buying a new advance in the next day or so in readiness.
Colin
Last edited by colin gray on Sat Jul 28, 2018 8:32 am, edited 1 time in total.

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#32 Re: Running Temperature etc

Post by mgcjag » Sat Jul 28, 2018 8:11 am

Hi Colin...did you not see my post a few above.....you do not have to quote the whole of the post your replying to..please edit it down to the relevant sentance etc. Or just use the Post Reply function...it does use up valuable server space....thanks... Steve
Steve
1969 S2 2+2 & Building a C type replica

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#33 Re: Running Temperature etc

Post by colin gray » Sat Jul 28, 2018 8:30 am

Sorry Steve, I will have to hone my forum/laptop skills, I did try to just quote a certain part of a post but it put the whole thing up. I will edit it down if I don't manage to get just the part I intend to quote.
Cheers
Colin

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#34 Re: Running Temperature etc

Post by colin gray » Sat Jul 28, 2018 9:33 am

42south wrote:
Fri Jul 27, 2018 9:44 pm

For Interest he recommended using the vacuum advance unit 54405202 which is the one listed for the 1982-89
I have just ordered a new advance unit as above just wanted to ask is it a straight replacement job on the dizzy or are any mods needed to the distributor I assume it just moves the bottom plate in the dizzy the opposite way to advance rather than retard the spark?
Vacuum source TBA
Cheers
Colin

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#35 Re: Running Temperature etc

Post by jagwit » Sat Jul 28, 2018 11:37 am

colin gray wrote:
Sat Jul 28, 2018 9:33 am
I assume it just moves the bottom plate in the dizzy the opposite way to advance rather than retard the spark?
I can not comment on mounting the unit with regard to your particular dissy but I doubt very much that any mods would be required. Its a very simple job on the oem DD6/XJS/XJ12 dissy.

You are correct, it just moves the bottom plate in the opposite direction.

Please note that fitting the new unit MIGHT change the timing due to the advance unit arm possibly not having exactly the same length or being in the same position as what the retard unit had. So...

I recommend that
1) with no vacuum connected you check/set the timing before you remove the retard unit and note the idle rpm;
2) Install the advance unit (no vacuum connected), check/set the timing to be exactly the same as with retard unit. Now idle speed should be EXACTLY the same as before.

Now, just for amusement, connect a rubber pipe to the advance unit and suck on it hard as you can and tell us what happens....

Now connect the pipe to your chosen vacuum source.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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#36 Re: Running Temperature etc

Post by colin gray » Sat Jul 28, 2018 12:35 pm

I have been checking things in advance and removed the vacuum unit pipes and blocked them off. I noted they fit to the bypass valve so I am not sure if this is manifold or likely to be similar to ported vacuum. I also noted two blanked of pipes 1 at the front right manifold and one at the left rear manifold. I've no idea what they are for.

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#37 Re: Running Temperature etc

Post by jagwit » Sat Jul 28, 2018 1:27 pm

When you say "bypass valve", are you referring to the bypass valves on the carbs?

My own car does not have any pipe connections to the bypass valves but another car I recently worked on, did have such pipe connections. I have not bothered to find out what their actual purpose is (some form of barometric correction perhaps?), but I can not see that they could have anything to do with vacuum advance / retard.

The two blanked off pipes 1 at the front right manifold and one at the left rear manifold, can be used for manifold vacuum. Ported vacuum will be to a connection on the engine side mounting flange of a carb.

There are also two manifold pressure points on the cab side of the left rear manifold (RHD car) which are used for gearbox shift modulator (auto) and brake vacuum.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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#38 Re: Running Temperature etc

Post by 42south » Sat Jul 28, 2018 9:27 pm

Hi Colin,
the distributor vacuum unit never connects to the carburettor bypass valve.
If you hold to the Jaguar method it is either connected to the port on the top or the bottom of the left rear carb depending on whether you have an advance or retard vacuum module fitted.

If you want to run with Philips idea of vacuum source it connects onto an inlet manifold vacuum connection.

Those carb bypass valves can be leak sources as well. They were only fitted to meet US emission regs, I blocked mine off with a bit of solid gasket paper in place of the gasket fitted. As Philip says some of them have a vacuum connection pipe on top, some don't. The early ones had the vacuum pipe, the later ones had an internal vacuum source. They need vacuum to operate the rubber diaphragm inside them which allows the extra fuel in on snap throttle closing during deceleration, to prevent lean mixture with associated popping in the exhaust.
For some good pictures and description of these valves go to

http://www.buckeyetriumphs.org/technica ... CarbsI.htm

for your blanked off manifold pipes, my car has the same ones and they are blanked off, apart from one of the left hand rear ones which supplies vacuum to the brake booster.

Cheers
Mark
Mark Brown
1971 S3 Etype
Son: when I grow up, I want to be a pilot
Dad: You’ll have to choose.

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Barry
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#39 Re: Running Temperature etc

Post by Barry » Sun Jul 29, 2018 8:03 am

All very interesting on vacuum, but I thought this thread was about RUNNING TEMPERATURES!

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#40 Re: Running Temperature etc

Post by colin gray » Sun Jul 29, 2018 8:25 am

jagwit wrote:
Sat Jul 28, 2018 1:27 pm
When you say "bypass valve", are you referring to the bypass valves on the carbs
Hi Phillip, Yes the Carburettor bypass I tried to attach an image but the phone file was too large.

Hi Mark, Well that is where the distributor vacuum is connected and I was surprised too, I will have to check if they are creating vacuum or if the port should have vacuum applied. I also may blank them off as well as any other emission stuff not required in the UK, I can not believe after almost 9 years of ownership I am only just looking at the car this closely (just been driving and enjoying it I guess) I will check out the link you attached thank you.

Hi Barry, I know it started as running temperatures and it still kind of is, we have got here as a result of the temperature discussion and apart from starting a thread elsewhere not associated and with no continuation it kind of is what it is.
It has helped me understand quite a bit including the fact my car runs retard Vacuum unit creating extra engine temperature. I am grateful to everyone for their contributions and feel it has been worthwhile finding the knock on affect different things have had.
So to all those who have contributed so far I would like to say a big :thankyouyellow:

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