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SIV diagnostic advice ??

Discussion in '"Stock" Alpine' started by SIVAllan, Mar 24, 2009.

  1. Bill Blue

    Bill Blue Platinum Level Sponsor

    You could try grounding the wires manually. Say use a screwdriver, with you supplying the ground. If you think "That tickles", you have a problem. If the screwdriver lands at least 15 feet from the car, spark is okay.

    Seriously, all I can recommend is to wait until the engine starts to act up before checking the spark. I think you know what a good spark looks like.

  2. SIVAllan

    SIVAllan Donation Time


    Thanks again!

    Tomorrow the car comes off jack stands and will be test driven.

    IF it breaks down again, the spark will be tested manually.

    I don't mind a good jolt if it proves a good spark and rules out a variable.

    I would also like to ground the ancient factory distributor as a failsafe.

    I'm unsure how to do that.

    Possibly run a wire to the chassis from the fasten-down bolt for the distributor?

    I have no reason to suspect the distributor's electrics other than the fact that the car is not working.

    Regarding spark, I also have a new distributor from Holland but a parts house guy said it needs a 6 volt coil which he sold me. Not sure about which coil, 12 or 6 volt.

    Bottom line is parts are in inventory here to test the distributor and coil if I can get them installed correctly, also some new plugs are available.

    These are spare/backup parts for emergency use but this is an emergency.

    Thanks again, :)

  3. Bill Blue

    Bill Blue Platinum Level Sponsor

    Allan, grounding the distributor is an excellent idea. I'd wait until it starts to run rough, then touch a grounded wire to the dizzy body. If touching the dizzy makes a difference, the hold down bolt should make a decent permanent ground. Any nonrusty bolt or screw on the engine or body should provide a ground.

    Don't know what the guy would be talking about, when he says the dizzy needs a 6 v. coil. Sounds like a rip off. There are basically two kinds of coils, with or without internal resister. All 12 v. point systems require a resister. Matters not a hoot whether the resister is in the coil or is setting alongside the coil, such as the stock Alpine setup. You do not want to use an external resister if the coil has an internal resister. That would lead to very weak spark. If you have a coil marked "12 v.", it should work with any dizzy, but do not use the external resister.

  4. puff4

    puff4 Diamond Level Sponsor

    Many years ago I used a white 'aircraft' tank liner product - I may have got it from Eastwood - and it worked really well - still on there today, and it's got to be 25 years now.
  5. nickraymond

    nickraymond Donation Time

    I haven't checked through all the pages so apologies if these have been said before:

    Dodgy fuel pump?
    Fuel vapourising?
  6. Jim E

    Jim E Donation Time

    Just to be certain how about a compression test, points gap check and a timing check. Just to know it is all good. Would also put a Uny-syn {SP?} on the carbs to see if they are both sucking the same.

    To me the tank liner in the cross over going away is a little troublesome. Thinking if it disolved may gum up the carbs.

    Still if I am following this it sort of looks like it is heat related or is it load related.

    Had a straight six that would do this and it drove me nuts, turned out it was the fuel pump arm and the cam lobe worn, noticed this when I took the old fuel pump off to put on the motor I had installed.... Then once on my SV with the 4 cylinder I had a goofy problem that I tried all sorts of stuff to fix over and over dang thing just would not run right. Turned out I was the goof and had crossed a couple plug wires. The rotor with the moving metal tab was a good one too. Or the time we had no spark and swapped dizzys but had to use one wire from the old dizzy... guess what was bad... then the time I forgot the chassis ground strap. Reversed coil polarity is always good for a laugh but not as good as trying to sync carbs with a sunk exhaust valve. Then the time a guy at an events fresh built motor was running hot and his mechanic had tried everything water pump, recore radiator and such he ask me to look at it and it took aboput 3 seconds to notice the fan was on backwards. But that is usually how it goes once you figure it out it was right there in front of you all along and typically something simple. So I find when I get to the point I do not know my head from my elbow it helps to stop and start over at the basics and always change one thing at a time.
  7. Andrew

    Andrew SAOCA Web/Graphics Service Donation Time

    Would it be worth while installing an AC styled 12V / Electric fuel pump?
    If the mechanical pump or cam is worn this would be the best fix.....would it not?

  8. RootesRacer

    RootesRacer Donation Time

    Any 12v pump will work, I'd stay away from the AC style pumps unless they are points/contact free.

    Now if you are sucking air in, these pumps will have the same problem.

    If you graft the pump far enough back, you may uncover where your leak is becuase it will push fuel out it instead of sucking air in as it is now.
  9. SIVAllan

    SIVAllan Donation Time


    Just to bring everyone up to date ... :)

    Yesterday worked on the car until late. Once the fuel line clamps were tightend REAL TIGHT, and the same for each "join" for the fuel tanks and crossover tubes, "the" problem changed somewhat.

    The car ran sorta good on a test drive thru the hills in the neighborhood.

    But it still stumbled only not as bad as before.

    It seemed to have gone from gas starvation to too much gas.

    The spark plugs fouled black and were replaced with new one on the roadside.

    Gaps were checked before installation.

    After a few blocks, they fouled again and were removed, wiped off, reamed a little using feeler gauge as a reamer, and reinstalled, only to foul again.

    The WIP zeniths only have one adjustment doable on the roadside -- the air/fuel mixture scew at the top of the carb.

    So that screw was turned all the way out, and then the car tested, then half a turn inward, test, half a turn, test, etc but no luck.

    So it was tested from the other direction - screw was turned all the way in, then out half a turn etc etc also no luck.

    The plugs kept fouling.

    After AAA brought the car home, I began to static time the car to 6 degrees BTDC as indicated in my books.

    That's where it is now - with the following plan for today's work.

    1--drop in NEW distributor - model 45D - from Arnould in Holland to be more sure the spark is good;
    2--complete static timing;
    3--install an inline fuel pressure regulator set to 3 pounds - the max the Zenith WIPs should have to deal with
    4--install fuel pressure inline gauge (returned the other one)

    6--if problem persists - remove top from carbs to see if any debris is in there OR-- put other carbs back on the sunbeam...

    Does this make sense as a plan of attack?

    If not please let me know :) as I'll check email every so often.

    Thanks in advance again!!!!

  10. RootesRacer

    RootesRacer Donation Time

    You didnt mention if you installed an electric pump, if you did, then 3 psi is too high for the zeniths.

    If you are still running the mechanical pump, you wont hit 3 psi, so no worries.

    Go no higher than 2 psi on these carbs else the needle and seat cam be overcome and the fuel level is too high possible overflowing the carbs.
  11. Bill Blue

    Bill Blue Platinum Level Sponsor

    Allan, a couple of things you can check.
    First, is anything holding the float needle valve(s) open?
    Second, have you checked float height?

    I've never messed with the Zeniths, so don't know specifically what I'm talking about. But incorrect float height can lead to either rich or lean running with any carb. It may be your floats are set too high because the shop was trying to compensate for inadequate fuel delivery and are now flooding the carbs.

  12. SIVAllan

    SIVAllan Donation Time


    I put on another AC factory mechanical pump. It's NOS, from inventory of 'backup' parts.

    The fuel pressure regulator will be set to 2 psi.

    This should eliminate from consideration "too much fuel pressure."

    IF THE darn fuel pressure inline gauge begins to work, it can eliminate "too little fuel pressure."

    Bill - If the other items in the plan of attack do not produce success, then the tops will be removed from the carbs to determine if any crud can be seen.

    Alternately I could switch back to the other set of carbs.

  13. Bill Blue

    Bill Blue Platinum Level Sponsor

    Be sure to check the float settings when you have the tops are removed.

  14. SIVAllan

    SIVAllan Donation Time

    Bill - the assumption is that the carb internal check will still be needed :) :) ??

    I would bet on it if you think so !!

    My Zenith factory tech note is not as clear as I'd like but it does indicate that:

    "Petrol level
    Whilst this can be varied within certain limits, the usual setting is 16mm (5/8 in) down from the edge of the floatchamber, measured by a depth gauge resting on this face with the gasket removed.

    When checking the level ensure that the float bracket is right down in the slot by placing a piece of metal to hold it there, as the bouyancy of the float will tend to lift the bracket after the cover is removed.

    Make sure the carburetter is level by using a suitable spirit level across the top face of the floatchamber, with the cover removed. "

    So that's 16 mm down from the face upon which the gasket rests excluding the gasket thickness -- with the float held down to it's lowest level by it's bracket -- if I am reading this correctly...

  15. Bill Blue

    Bill Blue Platinum Level Sponsor

    I see why you have not been keen on checking this vital adjustment.

  16. SIVAllan

    SIVAllan Donation Time

    I took the top off a parts WIP zenith and the float can easily be checked to see if it is sunk or stuck - but how to adjust the float level (if needbe) is not apparent.

    But now I'm thinking the fuel issue is not the central issue. The carbs get fuel. I don't see a fuel starvation as before the air leaks were fixed.

    I don't think spark is present.

    The ancient stock distributor was replaced with a new one, a model 45D which looks almost identical to the factory issue model, except it has no vernier.

    A fat rain drop went inside the distibutor so I hope that's not terminal ??

    I laid a spark plug with wire attached, on the valve cover, spun the engine, but saw no spark.

    Shouldn't that produce a good blue spark?

  17. Bill Blue

    Bill Blue Platinum Level Sponsor

    Not if there was no gap, i.e., the metal of the plug terminal was touching the valve cover. That is almost impossible with most modern spark plug wiring. But if there was a gap of less than say, a half inch, you should have seen a blue spark. A good test device is to take an old, but not totally trashed plug, remove the outer electrode (or bend it out straight). Simply place the wire over the plug terminal, lay the plug onto the valve cover and spin the engine.

    Typically, the float does not directly touch the needle valve. Instead, there is a small finger of brass soldered onto the float, the finger touches the valve. The finger can be bent to provide the correct setting. But once again, don't know about the Zeniths.

    A single drop of rain is not terminal for a good dizzy. Condensation can be much more than that.

  18. Nickodell

    Nickodell Donation Time

    Or, as someone said 5 days ago, You need to check the entire fuel system, from the tank to the carb. jets. It appears that the engine gets enough fuel to function until some dirt gets sucked into a restriction like a jet. I'd replace the float chamber needle valves, and check that the fuel level is correct. Also, clean or replace the carb. jets.:)
  19. SIVAllan

    SIVAllan Donation Time

    Bill - An old plug was used as described to no avail. I also tried a new plug, holding on with rubber handled pliers, and moved it about the valve cover in close proximity (1 inch down to 0 ) but no spark.

    I have no clue unless the rain messed up the distributor. That can be checked by swapping back to the old one.

    Nick, Bill, everyone reading this thread - I have been loathe to open a carb. I've never done it before today, but will in the next day or so if needbe.

    The WIP zeniths have a float in one chamber, and the float bracket extends through a wall of the chamber into a tiny 2nd chamber.

    I see the bracket that goes down as the float goes up, and which connects to a valve at the bottom of this tiny secondary chamber.

    To inspect that jet, one would need to remove the float as only a small segment of the overall jet-top can be seen beneath the bracket.

    To change that jet, for sure the float would have to come out.

    To bend the float bracket (adjust the float level) it sure looks like the float would need to come out - to me anyway.

    There must be a way to remove the float but at this time the term "magic" comes to mind :) .

    NIck - I should have followed the 'entire fuel system' advice sooner. Mea Culpa.

    I think the line between the carbs back to the tanks is now reliable and clear.

    I can't vouch for the tanks - even though split open by a radiator shop boiled out and red coated. I think some or all of the red coating came off and went through the fuel system, along with whatever may have been stuck to the loose coating.

    I can't "prove" that without opening the tanks - as in removal and back to the shop.

    But now there seems to be plenty of fuel but NO SPARK.

    Somehow I must re-find the truant spark.

    I suspect that rain terminated the distributor.

    If not that, then I'm not real sure. Coil perhaps??

  20. Bill Blue

    Bill Blue Platinum Level Sponsor

    Allan, the most a drop of rain can do in the dizzy is temporarily mess up something. Say, land on the points, so as they break, current flow continues. Can you dry it out with a heat gun or hair dryer? Maybe carefully with a propane torch?

    No point in messing with the carbys until you get spark.

    Otherwise, it appears you are back where you were a year or so ago. Congrats on going full circle. Chasing your own tail can be so much fun!

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