Page 2 of 2 FirstFirst 12
Results 11 to 18 of 18
  1. #11
    Join Date
    Jan 2010
    Location
    Martham, Norfolk
    Age
    64
    Posts
    216
    My immediate thought was early Dax, but so many replicas are clones of clones so it's difficult to know. But it's interesting that the AA's advertising agents have decided that the image of a Cobra driving holiday will pull the punters in. Just shows what a cool car it is.

    Oh boy, that's a difficult one dave.n. You've already tried the obvious. Don't pull the heads: A compression check will tell you if the valves and rings are ok. Is the engine starting easily? Is your fuel fresh?
    Henry
    'I tell you, we are here on earth to fart around, and don't let anybody tell you different.' Kurt Vonnegut
    DAX DeDion Chevy 350ci

  2. #12
    Join Date
    Aug 2011
    Location
    Birmingham
    Posts
    343
    Not a RAM - it has visible / external boots hinges. RAM has internal hinges.

  3. #13
    Join Date
    Dec 2003
    Location
    se-london, england.
    Posts
    3,437
    Quote Originally Posted by Cob View Post
    My immediate thought was early Dax, but so many replicas are clones of clones so it's difficult to know. But it's interesting that the AA's advertising agents have decided that the image of a Cobra driving holiday will pull the punters in. Just shows what a cool car it is.

    Oh boy, that's a difficult one dave.n. You've already tried the obvious. Don't pull the heads: A compression check will tell you if the valves and rings are ok. Is the engine starting easily? Is your fuel fresh?
    Henry
    Hi Henry, thank you for your advice. I do have a bit of barsterd problem. I can't actually get a compression kit on the damn thing. To remove two of the spark plugs it's steering linkage out and exhaust manifold off (a real nasty and long job on my car). full tank of fresh juice. always starts PS You and Dave B are probably right on early Dax.
    Dave AKA billy no mates . SRV8

  4. #14
    Join Date
    Jan 2010
    Location
    Martham, Norfolk
    Age
    64
    Posts
    216
    Quote Originally Posted by dave.n View Post
    Hi Henry, thank you for your advice. I do have a bit of barsterd problem. I can't actually get a compression kit on the damn thing. To remove two of the spark plugs it's steering linkage out and exhaust manifold off (a real nasty and long job on my car). full tank of fresh juice. always starts PS You and Dave B are probably right on early Dax.
    Ah. Pulling plugs isn't so easy then. But I think you've covered the rest of the bases. Just a thought: Did this missing and backfiring problem start all of a sudden, or did it start as a tiny misfire and loss of power and then gradually get worse?

    If you have some burned valves it will be very low on compression on those cylinders and you'd get backfiring because unburned fuel will get past those cylinders to be ignited in the headers. Worn piston rings will also drop compression, but the crank pressure will go up (chuffing at the breather) and there will be a lot of white exhaust smoke (oil burning) and high oil consumption. Unless someone can think of another fueling or electrical thing to check out I don't think you have much choice but to pull the headers off and steering joints off in order to test the compression. As you say, it's a right bastard!

    There is another thing that causes backfires: Air being drawn into the headers via poor joints at the head or cracks in welds, etc. But it's mostly pop and bang on the overrun and won't significantly affect power or smooth running - just sound rough and horrible.
    Hoping we can help you get to the bottom of this.
    Henry
    'I tell you, we are here on earth to fart around, and don't let anybody tell you different.' Kurt Vonnegut
    DAX DeDion Chevy 350ci

  5. #15
    Join Date
    Dec 2003
    Location
    se-london, england.
    Posts
    3,437
    Thanks Henry. Just renewed fuel filter (clutching at straws) (made no difference). floor it and it takes off but still seams like it's missing, backfires. driving it normally it surges and misses and a backfiring. always had a little chuffing at the breather. always had a bit of white exhaust. Doesn't use any oil. Headers and exhausts are a year old but have recently had to reseat the headers. Compression test it is then. a lot easier to spring the heads though.
    Dave AKA billy no mates . SRV8

  6. #16
    Join Date
    Jan 2010
    Location
    Martham, Norfolk
    Age
    64
    Posts
    216
    Ok Dave, Before you strip the motor: You say 'floor it and it takes off'. That sounds promising. But 'surges and misses and backfiring' doesn't sound to me like valves or rings. I'm pretty sure that the symptoms to expect with burned valves or worn/broken rings would not include much in the way of surging (you can tell I've had my fair share of knackered cars). That still sounds electrical to me. And intermittent ignition would produce misfiring and surging and backfiring, whereas intermittent fueling would produce misfiring and surging without the backfiring. Have you checked that the ignition system is getting a reliable 12v supply?
    'I tell you, we are here on earth to fart around, and don't let anybody tell you different.' Kurt Vonnegut
    DAX DeDion Chevy 350ci

  7. #17
    Join Date
    Dec 2003
    Location
    se-london, england.
    Posts
    3,437
    Quote Originally Posted by Cob View Post
    Ok Dave, Before you strip the motor: You say 'floor it and it takes off'. That sounds promising. But 'surges and misses and backfiring' doesn't sound to me like valves or rings. I'm pretty sure that the symptoms to expect with burned valves or worn/broken rings would not include much in the way of surging (you can tell I've had my fair share of knackered cars). That still sounds electrical to me. And intermittent ignition would produce misfiring and surging and backfiring, whereas intermittent fueling would produce misfiring and surging without the backfiring. Have you checked that the ignition system is getting a reliable 12v supply?
    Aha????? Henry are you suggesting the battery could be knackered ????. This could be a pointer. I am not running any electronic ignition (haven't done for 12years) so there isn't any source of spark boost. I'll run a tester over it at weekend as I'm working now until then. not long had the alternator rebuilt (3-4 weeks) as it wasn't charging.
    Dave AKA billy no mates . SRV8

  8. #18
    Join Date
    Jan 2010
    Location
    Martham, Norfolk
    Age
    64
    Posts
    216
    Quote Originally Posted by dave.n View Post
    Aha????? Henry are you suggesting the battery could be knackered ????. This could be a pointer. I am not running any electronic ignition (haven't done for 12years) so there isn't any source of spark boost. I'll run a tester over it at weekend as I'm working now until then. not long had the alternator rebuilt (3-4 weeks) as it wasn't charging.
    I'd suggest starting with the easy stuff before rushing out to buy more kit. The battery is not necessarily at fault, although you do need to check that it's in good order. Use a hydrometer to test the specific gravity of the battery's cells, and if one or two are lower than the rest it indicates they are sulphated. There does come a time when the battery is beyond recovery, but IMHO most batteries are scrapped far too soon. 'Smart' battery chargers can recover sulphated cells to quite a degree. A healthy battery should hold 12.75V or more. 12.5V is adequate, and if it can't achieve 12.5V after a good charge the battery is getting tired. However, as far as I understand, it will still run your ignition system, and voltage probably has to be a bit lower before the ignition falters. However, 'voltage drop' across connectors it the most likely cause of problems, and there are several connections to check: Battery terminals. Battery earth (ground), and then check the rest of the ignition circuit which includes the ignition switch on the steering column and any relay and/or fuse. Faulty connectors being the most likely suspects. There can also be breaks in the wires, or insulation chafed through allowing shorting out. One way to make certain about the low tension (12v) side of things, is to 'hot wire' the battery direct to the coil (via an in-line fuse for safety). That way you know you are feeding the ignition 12+volts and you bypass any suspect wires and connectors. But don't leave the battery charging the coil for long if the engine is not running as it will heat up the coil.

    I think it's worth reading this: Ignition System – Auto Repair Help it might make you consider re-fitting your car with electronic ignition. But it should be possible to make the car run with old fashioned points ignition so long as everything is in good order.
    Henry
    'I tell you, we are here on earth to fart around, and don't let anybody tell you different.' Kurt Vonnegut
    DAX DeDion Chevy 350ci

Page 2 of 2 FirstFirst 12

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •