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Thread: S-type 3,4 1966 engine problem

  1. #1
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    S-type 3,4 1966 engine problem

    Hello

    Im new on this site.

    And have problem with my s-type 3.4 -66.
    It starts and go for a 10-15 minutes. Then your hear it stop.
    f it starts up immediately after it has stopped. It goes so unevenly. But if you wait 5-10 minutes then it goes well again.
    And stop after 10-15 minutes again.
    I have replaced the ignition coil, distributor cover, switch, cond,voltage control unit
    and cables to spark plugs. Left side petrol tank and fuel pump is new.

    I restored the carburators. The idle speed is sometimes a little too high. 1200-1300 rpm.And can not lower nothing happens.

    Dont know what more to do. And what is wrong with the car

    Thank you
    Mikael Grewe new member

  2. #2
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    Hello Mikael,

    It's difficult to diagnose, particularly from afar. I would suggest that a full set up and check be done. If you don't have a workshop manual, I would suggest getting one as it gives so much information.

    Checks such as compression on all cylinders, which should all be within about 10 to 15 psi of each other for reasonable running. It would be nice to do a check of the valve clearances also but that is a fair bit of work and probably not relevant to your problem, unless of course the compression figures are bad. If it is still on points set them to a 15 thou gap (Sorry for the imperial figures but I don't know the metric equivelant). Check the advance mechanism on the distributor is free. Check the ignition timing. Check the float levels are correct in the carburettors. Check that both carburettor airflows are reasonably balanced.
    If you take the air intake pipe off the carburettors to see if it is flooding when it's running, this will also give black smoke from the exhaust pipes. Can you get it to run long enough for the starter carburettor to switch off or simply disconnect a wire to the solenoid and see how it runs when it warms up?

    I'm suspecting over fuelling at start but in the case of a problem that is not easily solved I like to know the state of all things that affect the smooth running

    Alec
    MK 2 3.8 (Long term restoration), 2.5 P.I. Triumph saloon, 564 Hymer motorhome.

  3. #3
    Senior Member cass3958's Avatar
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    It is very difficult to diagnose a problem from a description and a lot of these types of problems are not one thing but a couple or more that can only be located by trial and error checks.
    If the car starts and runs but only for a short time I would ignore almost everything Alec has suggested as most of them are terminal problems that would affect the car on start up or stop it from starting altogether.
    Engines need compression, fuel, timing and a spark to run. You obviously have compression so ignore this. The timing seems fine or the car would not start in the first place. So this leaves spark and fuel and we have to consider the fact the car runs and then stops when hot but seems to start again but roughly after cooling slightly. On the spark side we could be looking at plugs. Plugs can break down when hot so I would change all the plugs to start with. As Alex asked do you still have contact points in the distributor if so remove the points and either clean them or replace them. If you have an electronic module type ignition coil check the module is not breaking down. Normally they either work or not. Lastly on the spark side check the rotor in the distributor. These have been known to crack or the rivet comes loose in the top and heat would magnify a problem like this.
    On the fuel side you have refurbished the carburettors and changed one fuel tank. Is this the tank that you are drawing fuel from or is it from the old tank? I would check for debris in the fuel lines and in the float bowls. When the engine stops check the fuel level in the glass fuel bowl to see you are getting fuel feed to the engine. The XK engine is pretty reliable but also very strong and could run on three cylinders so if one carb is starved of fuel the engine might stop and then restart on three, sound awful and then when the carb is fed with fuel again jump back to six.
    Theses are all guesses as nothing can beat standing in front of the engine to hear what it is doing.
    Is your S Type on the International S TYpe register at http://www.jagstyperegister.com/ if not please come along and join us. We have a forum there which is dedicated to the 1960s S Type at http://www.jagstyperegister.com/forum_new/ where there are a lot more knowledgeable people than me who own S Type Jaguars that will be able to help you. Look forward to hearing from you again to see if you can solve your problem.
    Rob.C.
    1968 Jaguar S Type 3.4 Auto Old English white
    2016 Jaguar XF Sportbrake
    1966 Ford Anglia 1760 X flow
    1993 Yamaha FJ1200
    2012 Old English Sheep Dog White and Grey

  4. #4
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    Hello Mikael,

    have you made any progress, some feedback from you may help us assist you with your problem.

    You said that you overhauled the carburettors, did you have a manual to ssist with the provisional settings? Are you aware of the need to centre the jets?

    Alec
    MK 2 3.8 (Long term restoration), 2.5 P.I. Triumph saloon, 564 Hymer motorhome.

  5. #5
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    Definitely sounds like a fuel/vacuum problem.
    Way to detailed to explain how the rebuild and set up the carbs.

    Could be one or a couple of problems including water/dirt in the fuel along with carb setting and air/vacuum leaks.
    The only thing I would suggest you try is, with the engine hot and running, spray some carb cleaner around the carb mounting area and along the inlet manifold.
    If the revs increase, you have an air leak. If the revs stay the same, you have eliminated an air leak problem.
    Jaguar Keys & Remotes
    Castle Locks
    196 London Rd
    Hadleigh
    Essex
    SS7 2PD

    07792 552423
    01702 555557
    castle.locks@btinternet.com

  6. #6
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    Also seen vapour lock in fuel lines where air-con is fitted to some old jags
    Jaguar Keys & Remotes
    Castle Locks
    196 London Rd
    Hadleigh
    Essex
    SS7 2PD

    07792 552423
    01702 555557
    castle.locks@btinternet.com

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