I am in the final stages of fully restoring an E type from 1963, meaning with the 3,8 litre engine.
I have in this rebuild also restored the engine 100% and have replaced the original distributor with a non programmable 123 electronic device. So my problem is, what is the correct “program” for a 3,8 litre 9:1 compression, 3 standard overhauled SU HD8 carbuettor set up?
I have also fitted reccommended spark plug cables.
Do I need to adjust the gap for the spark plugs from 0,64 mm / 0,025inch or may I leave them as per manufacturers reccommendations?
Ove, I am sure you will get better answers from others but I installed the 123 on my 67 4.2 engine and I used a benign curve, 1 if I recall. I went to their website and they provide data on the various curves. It would probably help a lot if you could publish the curves (chart actually) for your specific product to your post, then we can disect them and come up with an answer, probably more than one!
My generic answer is to try and match the curves shown in the Bentley manual as much as possible.
My personal opinion is that unless you want to get your car setup on a rolling road that is instrumented to detect knock and you are confident that the components of your typical pump gas supply are going to always be the same, and you promise to never drive up long mountain grades on a hot day in too low of a gear, I would stick with a conservative curve, as shown in the Bentley manual.
I am running curve number 2.
It’s not that difficult to change the curve number with the distributor on the car. A small mirror and flashlight is required. I recommend you put a piece of tape with the curve number on the engine frame so you can remember it.
2 seems to be the sweet spot on a stock rebuild.
IMHO after 10 installled, when you drop the distributor in…PUT THE BASE WITH THE RED AND BLACK WIRE facing 9 oclock…or towards the firewall …You will basically be set minus a couple of degrees.
Good luck
gtjoey1314
I do not have a Bentley manual, could you be so kind to send me a link?
At the moment I have it at 2, but the car will not start, it started once with a lot of smoke. But that I think comes from fuel trouble and noxzle needles being incorrectly fitted in the damper pistons. Have adjusted them twice, all alligned now, but no start.
I think the torque curves vary from 3,8 and 4,2 sofar all say the same to be number 2. All are referring to 4,2 then.
So if you have the link to the Bentley manual, that would be a great help.
Ove
fre. 23. okt. 2020 kl. 16:07 skrev Harvey Ferris via Jag-lovers Forums <noreply@jag-lovers.com>:
Was it running before?
If so, its just your timing is WAY off. Set the base said above to 9 oclock.
The adjustment is SO defined that a HAIR clock wise or counter clock throws of the timing many degrees.
I hope your using modern plug wires and the right coil to match…
update, I just reread your post , It ignites but blows heavy gas or blue…Just turn the base to 9 where the wires come out you will be within 3 degrees.
Ove, my memory has failed me in that I can’t find the curve in Bentley. That said, here is a chart from Bentley that provides the key distributer parameters for a 3.8 engine.
The key takeaway of the graph is that the ignition is fully advanced by the time you reach 3000 rpm and the amount of advance is 25 to 30 degrees above your base timing, typically around 10 degrees.
I would agree with the others that if the car is not starting, it is not the curve you are selecting on the 123, it is simply that the unit is not rotated to the right position. It is a little nerve wracking but I have started fresh rebuilds by using a remote starter button and reaching in and rotating the distributor until the engine fires. Then you can fine tune it with your dial back timing light.
Problem when it was running was too much fuel. Found out that cyl 3,4,5,6 was full of fuel, where 1,2 was good. Checked then the needles on the piston in the carb and it was incorrect, needles on 3, 4,5,6
corresponding carbs were completely out.
Now re adjusted. All aligned. No start but a little unhappy slight firing is the case.
My engine is 100% new, built by one of the best on Jaguar XK engines in Norway, but they have done two silly mistakes, they have grinded away the timing marks on the damper and fitted the driver for the distributor to six o clock for the cylinder 6. Was before 3-4 o clock or something.
I have reconstructed the timing marks on the damper, by checking piston location, position of actual cam On the exhaust and the position on the adjustment «plate» marking on the exhaust cam itself. I have a tendency to think like you that all of this is a little inaccurate.
And making 5 and 10 degree marks on the damper by calculating 5 and 5 degrees before TDC. Roughly 10 mm each 5 degree on the circumference on the damper.
I do think I have to redo this again.
Silly. Really silly mistake by my engine builder…
Last time I did this and overhaul like this, engine started on first attempt…
S2 1970 FHC RHD.
But then nobody had removed timing marks or rotor driver on distributor.
Ove
fre. 23. okt. 2020 kl. 17:50 skrev j limongelli via Jag-lovers Forums <noreply@jag-lovers.com>:
You have a COMMON rebuild mistake…Your distributor is 180 degrees out…
You have to set your number 1 plug wire to NUMBER 6 then go counter clockwise from there…
Your car will start right up. DONT TOUCH THE CARBS Untill the firing order is correct, your phasing out the timing LOADING up fuel.
Good luck!
It has started. Then with a lot of unburnt smokey fuel. It stopped after suffocating itself after 30 seconds running. And 10 degree advance TDC match 100% marking on cam for cyl 6 in front plug lead is exact where TDC should be acc to myself. I may have been too inaccurate.
But I will recheck all of this again.
I think my own timing marking on damper may be the issue and I will follow the advice now by testing a little rotating the distr bit by bit.
And will keep you guys posted.
Ove
fre. 23. okt. 2020 kl. 19:08 skrev j limongelli via Jag-lovers Forums <noreply@jag-lovers.com>:
I would invest in a dial back timing light and then all you have to be able to find is TDC. Another thing I like about the dial back timing light is that you can check total advance, with and without vacuum advance.
I do have in mind to use that, once this «great» engine decide to start.
I will first of all make certain that the manually made TDC marks on the damper is really correct against exact piston TDC location.
All my checking so far has confirmed this.
But I will do this again.
That done, recheck the diode in the bottom of the distributor.
Then do a manual adjustment of distributor until engine starts. Hopefully these remedies solve this for me.
In the beginning the engine did not even suck enough air to even get the spark plugs wet. Compression good though.
In Norway, sadly to say there are too many professionals now that do not know fully what they are doing, my carbs where 100% dismantled, cleaned, vital worn parts replaced, assembled, but nozzle needles not fitted properly, they varied up to 1 mm from carb piston, that says it all.
Engine builder, one of Norways «best» on XK engines decided to grind away TDC marking on a brand new damper, in order to balance the crankshaft with pistons. Without even bothering to reconstruct this.
Life is full of challenges…
Next year I am 60, born four days ahead of 13/3, the E type and I will celebrate together and my guests will have one little Matchbox E type as a gift and memory of 60 years of this most beautiful car ever made.
On the exact launching 60 year anniversary date in Geneva, Saturday 13/3-2021.
My car is nearly exterior wise 100% identical.
Great fun.
Today done all again, physically.
TDC marking on damper could maybe be 1-2 mm out.
Readjusted 123 distr. And it started immediately. Very rough too much fuel. Stopped by itself after 10 seconds. without choke. Far less fuel-smoke, but more than 60 psi oil pressure. Which is good.
5 degrees C outside on 10/40 startup
oil.
Have also blocked vaccum connection to brakes on inlet manifold.
Turned down mixing screws one full turn. Only slight start, also now wo choke. Then nothing.
But, we are getting there. thanks to you guys I have more knowledge where to move.
So now the mixture could be the problem or play a little with distr. again. Do that first then.
Thanks😊
lør. 24. okt. 2020 kl. 10:38 skrev Ove Andreassen <ove009@gmail.com>:
Ove, if you are not using the choke lever on the dash, then you are also losing the effect of the fast idle cam. And generally you need a higher idle speed when cold. As I think you are suggesting by “too much fuel”, I would lean out the fuel mixture screws, gradually, until you need some choke to get it running. Alternately, you could just go ahead and turn in the regular idle screws to get a faster idle, until you get things sorted out.
Also, check that with the fuel pump on but the car not running, that there is no fuel coming out of the jet bridge in the throat of the carb. If it is, it might mean one or more of your float bowl needles is not seating. In my opinion, I would think it would have to be really really rich for it not to start and idle, so I wouldn’t fixate too much on richness as a primary cause.
Also, there are various rules of thumb but with no choke applied, the top of the fixed part of the needle assembly (the needle seat) should be about 2-3 mm below the top of the jet bridge. When you engage the choke lever on the dash, all 3 of the needle seats should drop down the same amount. Actually, looking in from the throat of the carb, they should drop out of sight.
When only fuel pump running I get no fuel
from the nozzles. It is only when I fool around with the choke it is coming excessive fuel and then a lot.
So thanks to you I have some logic and good steps forwards to play on. I think I am very close now. Engine just sound extremely good now. When it really want to😉
Many funny leaks have also been cured on the way…
Regards,
Ove A
lør. 24. okt. 2020 kl. 13:53 skrev Harvey Ferris via Jag-lovers Forums <noreply@jag-lovers.com>:
