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Thread: Crossflow not idling without a ton of advance

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    Tyre Kicker Dominic's Avatar

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    Crossflow not idling without a ton of advance

    Hi Guys,

    Having a strange issue that's come up recently, where my crossflow needs a lot more than 20 degrees advance to even idle. Any less than that and it just dies. I can't get an exact reading as I don't have an adjustable timing light, and the pulley mark is so far away from the markings on the chain cover. It will drive like this, but feels sluggish.

    Even with the advanced timing, combustion still doesn't sound right, and sounds like it might be continuing into the headers.

    Any ideas what would cause this? Other than very weak spark, I'm out of idea's.

    A bit of backround
    I have had the same engine set up for 7 years or so, but recently had a few issues with the car stumbling and dying, and then not restarting for half an hour. After cleaning up the idle mixture and still having the issue, it was pretty clear that it was an ignition problem, as the engine would start but now miss badly (on all cylinders), backfire and be extremely sluggish.
    I have cleaned up the earths and connections associated with the electronic ignition and brought a new coil for it. Re-timing the engine after all this, is where I noticed that it needed more timing than usual to run (historically has run happiest on 10 degrees static). It still feels sluggish, and I'm not willing to drive it very far, as I doubt I will make it home again.

    Engine specs
    1660 xflow
    BCF2 cam on vernier pulley - timed the cam in myself and it has run nice for the last 6.5 years, so unless its suddenly moved....
    Petronics electronic igniton and correct associated flamethrower coil.
    32/32 carb (too small I know, has run fine for years)

    Any thoughts on the above would be much appreciated. Unfortunately I doubt I still have the points set up I took out of it many years ago. Trying to avoid throwing a new electronic ignition at for the sake of ruling it out as they are $$$.

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    Re: Crossflow not idling without a ton of advance

    most likely a problem with the advance mechanism in the dizzy, if you i'd try another distributor

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    Mechanic

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    Re: Crossflow not idling without a ton of advance

    Quote Originally Posted by Graham View Post
    most likely a problem with the advance mechanism in the dizzy, if you i'd try another distributor
    Agreed, check your advance mechanism, the weights could be stuck, or sloppy springs are allowing the timing to bounce around.

    Ive seen similar behaviour from a engine that wouldn't advance due to stuck weights, so it need tons of pre advance to run at all, and when it did run it ran like a bag of shite at every engine speed except 7000+ rpm.

    Ive seen another with sloppy advance springs and the pivot points on the weighs were worn. It ran, but misfired, farted, and knocked and was generally horrible to drive.

    Ive also seen an engine that the ignition retarded as you increased the revs (dont ask...), that engine unsurprisingly need tons of advance to run also, and ran like a bag of shite.

    Old Fiats, a great education!
    Last edited by muckerbarry; 31-01-2019 at 09:00.

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    Tyre Kicker Dominic's Avatar

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    Re: Crossflow not idling without a ton of advance

    Cheers for the tips,

    I had a look at the mechanical advance, and everything seemed as it should, with minimal play, weights moving freely and returning to the no advance position with no issue.

    After testing and trying a ton of other things one by one, unplugging the tach (factory) from the coil seemed to fix it - though having plugged it back it, it now still runs fine.

    Im not convinced that im not going to have a problem in the future, though looking for a faulty part on a running engine seems like a pointless exercise.

    Thanks again for the advice, im sure I will be adding to this thread in the future

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