I am working on a 1969 e-type FH coupe 4.2 liter and have been trying for last 4 days to get the engine to run. I upgraded the dual carb setup to a triple weber 45 DCOE setup from classic jaguar, & OE distributor with EI conversion from petronix I even tried a distributor from 123ignition but I get the same problem. I set idle screws 1/4 turn from point of contact, air bypass screws in the closed position, mixture screws 1.5 turns out from lightly seated position; Cylinder # 1 at TDC, crank pulley at 5 degrees, rotor pointing to cylinder #1, wires arranged on the cap 1,5,3, 6, 2, 4 counter clockwise starting at cylinder 1. Crank the engine over it's extremely hard to start, choke fully engaged car starts and pops fire out of the carbs and tail pipe. I rotate the distributor advancing and retarding timing back and forth between 0 and 10 degrees makes no difference with popping. If I take the choke off it stalls out immediately, if I attempt to bring the idle up popping gets worst and the engine immediately stalls. I put a cylinder leakdown tester on with piston on TDC I am holding steady so the valves are sealed it's not a valve issue. I don't know what else to try I feel like I am overthinking this.

Help I am all out of ideas.

What about your valve timing? How did you set the valve timing (in detail).

Did the engine run before you swithched the carbs & distributer?
If so,then it seems like you don't have the dist. in corresctly yet
Don't forget----# 1 cylinder is at the "firewall"---

Good luck
Sal

Thanks for the quick responses...

The engine ran before the upgrades, I didn't do any internal work just the bolt on upgrades mentioned.

I timed the distributor to the cylinder closest to the firewall.

If the compression, cam timing and valve clearances are correct, then it sounds to me like you have an ignition problem. I run a fuel and ignition specialist shop and we have had problems with these electronic ignitions in certain Lucas distributors.

There is a very high probability that the rotor is firing between two poles rather than at a pole due to the pick up being in the incorrect position on the baseplate. (No amount of rotating the distributor will correct this!)

Take the vacuum pipe off the vacuum advance and try and keep the engine running at the lowest speed possible. (Can be damn hard.) Then with a strobe light set the timing to say 10 deg BTDC.

Switch off and then turn the engine by hand until the pointer is exactly on 10 deg BTDC. Now remove the distributor cap and determine exactly where the rotor is pointing..... It should be exactly opposite either 1 or 6 HT lead. If it is not, then I am right and vice versa!

If I am right then you may be able to correct it by screwing the vernier nut one way or the other by a large amount until the rotor position is correct. Or you must reposition the pick up on the base plate. Or throw it back at the supplier.

If you cannot keep the engine running as above, experiment by turning the vernier one way or the other while trying to keep the engine running and see what happens.

PS: How strong is the spark at the plugs? Is the coil matched to the new ignition unit?

If this all fails then go back to points and condenser and see what happens. If it still won't go, its the carbs to then check out.

I have never had a problem with 123 ignition though.

If you suspect it's the carbs, then do a jet audit on each one, and at the same time checking that nothing is blocked, float levels correct etc. What fuel pressure are you running? Weber 45s are extremely sensitive and should not exceed 3 psi with discharge blocked and not less than 2 psi pumping into a tin at the engine bay through a 1.75 mm orifice.

Good luck!

Well... my thoughts are a bit different. If you tried to get it run on three different distributors and in won't, my bet is on fuel delivery. Hard starting, popping and stalling sounds like a very lean mixture to me. Did you try to enrichen the mixture?

I followed Robin Phipson's advice I was able to get it to 8 degrees but then it died and did not restart. I hooked my timing light to the coil to distributor wire while cranking I had 700 to 800 rpm but when i hooked the inductive pickup from the timing light to each cylinder i saw no pulse. I tested and had no spart from the distributor to spark plug. Now I'm really confused. I checked the + side of the coil to ground while cranking the engine over the DVOM reads battery voltage, on the - side of the coil to ground reads 5 to 7 volts while cranking. Not sure what the spec is.

I was running a sports coil I just bought from SNG Barratt and switched it with a spare sports coil from a previous jag and still the same result..



Edited 1 time(s). Last edit at 12/11/2011 04:38PM by mastertechs.

You may be fighting 2 battles at the same time--
I would suggest to go back to the original points & cond.
dist.---with new points and cond.--set the gap on the bench-
original coil----If you can then get it to run---set the carbs
as best you can------then go to your electronic dist.


Good luck
Sal

Will do.. Thanks guys.

I'll go back to the original ignition and give you an update once it's installed.

Hope/don't hope it is something daft like a rotor tracking down to earth or faulty HT leads...!

Update; I installed a New lucas coil, new mechanical EI petronix distributor 10 degrees of timing and it fired right up on the first crank. The car idles alot smoother I am confident that I solved the ignition problem but I need help setting up the triple carbs the idle is low when off the choke and it falls flat on its face with some popping out the carbs and exhaust when you rev it.


I've been doing alot of reading on the weber 45 dcoe carbs. Some people say set the speed screws at .5 from initial contact,air bypass screws closed, set the mixture screws at 1.5 and go .5 of a turn until best results are had. The guys from classicjaguar suggested starting at 3. I tried both but still getting the same result I noticed cylinders 1 5 and 6 headers glowing red I shut it off before I hurt the engine. I am guessing I am too lean.??

I pulled the jets out they are 45 how do i tell if my jets are too small what is the best tool to help me tune the carbs. I bought a gunson color tune but it isn't much help.

Even a step by step procedure would helpful too.

Have you done a FULL jet audit on the carbs, starting with choke tube (venturi) size?

How are the carbs fitted/sealed to the inlet manifold? Some of those anti vibration kits leak like hell. Squirt some carb cleaner or gasoline around these seals with engine idling and see if there is any change in idle speed/note.

Are the carbs new or second hand?

45 sounds far too small for the idle jets. I recall 55 which is a 49.3% increase in gasoline flow.

I have all the jet specs at work which I can send to you tomorrow.

Is the brake booster/servo not leaking air and leaning things off? Blank it off temporarily if you are not sure.

Here are the correct jettings for the E-type from the Weber manual:

CARBURETTORS: 45DCOE9

CHOKES TUBES: 38 mm

VENTURIS: 3.5

MAIN JETS: 165

EMULSION TUBE: F2

AIR CORRECTION:190

IDLE JETS: 65F8

PUMP JETS: 40

BOWL JET: 50

NEEDLE + SEAT: 2 mm

FUEL PRESSURE AT CARBS: 3.5 psi MAX. AT IDLE. 2 psi MIN. AT FULL LOAD.


NOTES:

1) The carbs must be DCOE9. If not 9 the progression drillings may be in the wrong place.

2) The above specs are for high performance use.

3) 36 mm chokes are much better for an unmodified engine, normal road use.

4) If 36 mm chokes are used, a slightly smaller main and air jet may be used. Around 155 and 180.

5) For unmodified engine and normal road use, 1.5 mm needles + seats work better. This gives much better float level control over rough/undulating surfaces. If this causes starvation, increase to 1.75mm.

6) It seems your carbs are completely incorrectly jetted, especially on idle and progression. Far too lean.

7) Remember on no load the idle jets, via the progression holes, control the fuel flow right up to about 3000 to 3500 RPM. The main jets only come in around these revs.

8) Your 45 idle jets flow exactly half that of the specified 65 jets. That is terrible!

9) When getting 65 idle jets, ensure they are the correct F number, which must be F8. The F number determines the size of the idle air bleed in the jet, so you must not deviate from F8.

10) If it was me, I would drill your jets wherever possible, (using jet drills of course), to what I have specified above to save money and just get the beast running. After that you can fine tune with new jets.

11) Do not let people tell you the emulsion tubes are not important! Use F2.

12) Remember to not only synchronise idle air flows, but also at about 2500 RPM. The former on the 3 throttle stop screws; the latter on your linkages. Use an air flow synchroniser. Any unbalance will cause terrible idle and low revs roughness and popping.

13) I have done these conversions for customers over the years, but reluctantly. Unless you are going racing, the conversion is a complete waste of time performance wise and kills you on fuel. It is hard to beat triple HD8 SUs on a standard E-type when set up properly.

14) The original E-type fuel pump, or SU pumps from Mk2s, S-types, 420s and Series 1 XJs all have perfect pressure/flow characteristics for the Webers.

Here is a video of the car barely idling hissing from carbs popping out the tail pipe I go in on the throttle at the end of the video and it falls on its face popping and hissing until it stalls.

I took the spark plugs out to see what they look like and they a black fouled.

Have you done anything about correcting the jettings? Video sounds like the idle jets especially are horribly lean and that the carbs are out of synch. (I just commissioned a D-type replica with the jettings I give above your video and it runs perfectly.)

I have a 4.2 with headers no mods to the engine petronix ei mechanical distributor I have a 45dcoe152 with

Main jet 145
Emulsion tube f16
Idle jet 55f8
Pump jet 45

Mr Robinson the numbers that I gave you are a list of the jets I was able to identify. They are a little different from what you gave me. Does this confirm that the jetting is the problem? What's a good place to get the proper jetting.

Every single one of your jettings are wrong and all on the lean side except for the pump jets. Also you don't say what your choke tubes and air jets are. Please just follow my recommendations further up, starting with the choke tubes and jetting from there. I would go for 36mm chokes. The car has to run with those jettings as they are the official Weber jettings for the 4.2 and 3.8 Jag engines. Then you can fine tune from there.

Also adhere to my notes.

There must be Weber franchise in the USA. Google and see.

All Weber jettings start with the choice of choke tube size. For a road car, the smaller the better.

I am definitely going to follow your recommendations;

the choke tubes are 36, needle valve 2.00, starter air jet 85/f9

What do you recommend for the starter air jet?

Leave those as they are for now. The air jet on the opposite end of the emulsion tube as the main jet is most important.

Hi, my name is michael mcraney and I have had weber carbs on my 1970 E-type Jaguar sience 1974, bought new from Roy Rogers car parts in Little Rock, Arkansaw. I read the different problems and solutions and here is what is needed.
A. the jetting from Robin Phipson is a perfect starting point. ( 45 DCOE-9 weber carbs) use 38mm chokes with 3.5 auxiliary venturi.
B.you need to set the floot hight and drop. (5.0mm fuel shut off height, 13.5mm full droop setting) for each carberator. I use a digiyal caliper with the gaskit left in place on the carburetor under the floats. these are brass floats
C.the fuel needs to be 3-4 psi.
D. you need air flow synchronizer and learn to use. with engine running set each carb to the lowest even running speed with throtal linkage disconected, you will need a ditital rpm gage and the engine will run smothly from 500rpm.
E. timing set 10 degrees advance.
F.the idle adjustment starting point is 1 turn out from stop, use rpm gage to get proper maxmum idle speed from each carb with engine idling. connect throtal linkage after all tuning is complete, this will not efect the carb settings.
G. My 4.2 engine cranks by just pumping the aceerator peddle a few times and cranking the engine, no chokes are connected, idle speed 700rpms, probly gets 17 to 18 miles per gallon usa.
H. the engine runs much better with the air horns, mabe 500rpm quicker.
I. tried much smaller chokes, less performance, may be better with auto trans.
J. install rev-limiter, you will need all the help to keep power under control.
K. when the weber carbartor ballance is correct the low speed performance leaves lettle to be desired, with unbleavable aceleration throughout the rpm range compaired to when bought new.



Edited 1 time(s). Last edit at 02/18/2012 09:17AM by mmcraney.

Totally agree with Michael, except I still find that 36mm chokes are better for road use on an unmodified engine!

Thanks for your help guys I installed the new jets. The car starts and idles without the choke it's a completely different car.

"If 36 mm chokes are used, a slightly smaller main and air jet may be used. Around 155 and 180. "

I am running the 155's and 180 main and air jet

4.5 turns out on the mixture screws idle is around 800rpm but it idles a little rough and every now and then i get a poof from carbs 5&6. What should I do to get the car really dialed in?

I have added another video with synchronizer idle rpm and revving







Edited 1 time(s). Last edit at 03/06/2012 07:35PM by mastertechs.

Hi Rom,
I had bought 35mm chokes when I made many changes to my 1970 4.2L E-Type and used 1.4 main jets and 1.80 air corrector jets, Idle jets were F8 0.60 I beleave. Always check spark plugs. This set up was fine to about 5,000 RPM, with very good low speed response. As far as the backfiring back through the carburetors you still need to fine tune the balance between the three carburetors. This means set floats useing digital caliper with gasket in place, balance air with flowmeter and set Idle jets with a tachometer to the highest RPM for each cylinder. All this should and can be done as little 500 RPM and idle RPM around 700 RPM. This will be done before the linkage is conected. You will have to set your distribertor for static advance 10 dagrees and total advance around 38 degrees by 3200 RPM. Get rid of the points get electronic distributor, the most important thing you will need. I use platnum spark plug.
Other things that are nice: gas flowed cylinder head, long tubler headers and 280 degree cams.
MY (Excuse) for getting the Weber carburetors ($650.00) total cost new back then was the high temperature the engine ran and there were no other set up avalible. I had a exhaust tapet come lose around 6000 miles and the factory replacment head had a (C) stamp on the exhaust side by the #2 spark plug. There is a small (G) stamp on the rear behind the engine # by cylinder #1.
I had the radiator taken apart and cleaned and I never had any high temperature problems again,might have been caused by sand in the engine castings.

I certainly don't wish to rain on anyone's parade but the complexity of the Weber reportedly does not always allow for proper idling. I tend to heed such reports as I have had a dismal time sorting a proper after market Weber side draft to couple to a car born with SU or ZS.

I also would suggest, with all due respect, the Pertronix dizzy is still the same "stuff" made in Asia and of like quality as just about all new dizzys. An alternative would be to have the original Lucas unit properly recalibrated for the Jag. My dizzy man is the best in the USA and is likewise knowledgeable about Marelli and Lucas.

---

Regards,
Robert Kirk
kirkbrit@yahoo.com
563 323 1017
Moss distributor UK importer
Beat or match any retail/delivered quote

Robert,
I bought my E-Type roadster new May 2-1970 and have put less than 39,000 miles since. This car and other hobbies were bought for fun. I have made many planed performance improvments over time and would have put many more miies on it but for marriage, two childern and now two grand childern. I always planed to spend more time on my early hobies after retirment, had these forurms to reference back in the early 1970's I could have saved money, time and enjoyed this hobie even more.(can you even imigine setting weber carboretos without the information in this forum, I did! TIME AND MONEY) I never wonted a taxie cab and always felt the car could be brought up to better performance using the D-Type Jaguar engine modififcations and now newer modification's in balancing and lightning internal parts. This is not the cheepest toy to play with and you need to plan each step to stay within budget or have deep pockets. I probly bought over $500.00 plus in books over the last 42 years for referince information on this particular hobby and I am not finished, lots of fun if I can keep my helth and live longer.

Certainly no argument the internet has brought the "club support" to a new level and its good. The Weber is actually ideally suited for any car with solo intake to one chamber....not so a car with a siamese port feeding two...that I have learned is why they do not work that well on MGBs nor most 4 cyl LBCs...MGA TC probably not withstanding.

While the Lucs dizzy is prone to wear, imho, it still is light years ahead of most substitutes IF properly recurved....that was my only message.

---

Regards,
Robert Kirk
kirkbrit@yahoo.com
563 323 1017
Moss distributor UK importer
Beat or match any retail/delivered quote

Robert, I have always enjoyed cars and tinkering on my dads cars. The profesional car technicians had to come to our home numerous times to correct this miner thing or another after I checked things out. My dad never raised his voice or put me down because of these things. Before he passed away, while using my new truck to go shopping there was some damage to the rear tail gate when he got home, I had it reparied immediately. When I told him about the repairs ($305.00) and I intended to repair the truck anytime somthing happened he told me (I NEVER SAID ANYTHING WHEN YOU SCRATCHED MY CAR!) This was a great lesson for me and I enjoy smilling when I think about these things. English cars and Ferrari's were dream cars as I grew up an helped develop our thinking and problem solving to a higher level.

This may sound a little strange but I had a similar problem with my 4.2 with three HU8s and it was rebuilt but never run and the rings were probably not well seated. In my rush to get her fired up I didn't connect the vacuum hose to the mastercylinder. Without suck you won't get fuel. My engine would fire up and die. I don't know where the vacuum line is on a weber setup but you might want to see if you have a large vacuum leak at one end or the other on this line. good luck.