61Ferret Posted June 23, 2015 Share Posted June 23, 2015 Since owning the Ferret, I've done a number of mechanical/system repairs such as carb/fuel system rebuild and recently have done some ignition work such as new ignition wires, new plugs, condenser, points and distributor cap. Overall I have noticed an improvement but continue to experience backfiring and sputtering when quickly decelerating. If I decelerate gradually, there is no or perhaps only one small backfire. When standing still at idle speed, the engine runs smooth but do notice that when driving at a lower constant/steady speed of about 20 to 30 mph, the engine does not not sound/run smooth If I marginally accelerate it runs better. I have not adjusted the ignition timing since owning the vehicle and I'm now starting to think this is the cause but wanted to check with those who have more experience as ignition issues/adjustments is not my strength. Thanks in advance for your help and suggestions. Cheers, Terry. Quote Link to comment Share on other sites More sharing options...
Sean N Posted June 23, 2015 Share Posted June 23, 2015 Terry, I'm no expert on Ferret and someone like Richard F will probably advise, but in my experience B series engines have a tendency to backfire due to (excess) fuelling on the over-run. Checking the timing is certainly worthwhile, but my first thought was I wonder if the mixture is a touch rich? Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted June 23, 2015 Share Posted June 23, 2015 (edited) Hi Terry, Looks like Sean has set me up on this! Actually, I think it is quite a simple issue to explain. Where the exhaust leaves the manifold, there is an elbow with two tubes which engage with another elbow on the hull side. They are intentionally free because there is slight movement in the engine mountings. When new, the swaged ends of tubes are snug in the elbows, but after a long time the elbows wear inside and the steel tube tends to flake a bit on the swages making them loose. On the overrun, is where you get the backfire and this is a sure symptom of an air leak in the exhaust system. What can be done? Well you could find the modern equivalent of asbestos tape and bind around the tubes, or renew them. I have had success in the past by building up the swage by brazing and filing back until the just slide in the elbow with no slack. regards, Richard Edited June 23, 2015 by Richard Farrant spelling Quote Link to comment Share on other sites More sharing options...
61Ferret Posted June 23, 2015 Author Share Posted June 23, 2015 Sean/Richard. Thanks to both of you for taking the time to respond and offer some suggestions on how to address this issue. Shall certainly try the adjusting the fuel mixture and the two short pipes between the exhaust elbows are in fact loose, something that I was aware of because of the extra noise. When I first acquired the Ferret, there were some remains of a previous attempt to fill the joints and reduce the exhaust leak but there was not much there at the time and now nothing remains of that attempt. Fixing the two short pipes was on my list of things to repair but now that I know it may be causing the backfiring, I'll move it up a few spots on my list. Again, Thanks....greatly appreciated. Cheers, Terry. Quote Link to comment Share on other sites More sharing options...
tankdiver Posted September 20, 2015 Share Posted September 20, 2015 Hi backfiring on over run is Weaking of the mixture or exhaust leak the latter is most likely .I found new expansion tubes helped [ I have some of these] but from the exhaust the manifold I completely manufactured a new system with a small modern flexable joint The vehicle is totally transformed IT IS SO QUITE and is faster I now have done all my ferrets its also cheaper on fuel. NOTE A FLEXIBLE JOINT MUST BE FITTED due to engine torque will snap the manifold when I did an ac cobra years ago I took it for a run as it had a noisy exhaust I backed off the throttle when passing a lady with small dog The resulting bang sent the dog into vertical take off and a glare that froze steel from the woman Quote Link to comment Share on other sites More sharing options...
Skipv6797 Posted September 21, 2015 Share Posted September 21, 2015 Tankdriver, Could you take some photos of the modification you did and list the parts you used. regards, Skip Quote Link to comment Share on other sites More sharing options...
tankdiver Posted September 25, 2015 Share Posted September 25, 2015 THis is the format that I made for the last ferret using the material I had eg cut a co2 gas cylinder and welded two flange plates to the square box pipes and then welded them to the onto the cut down cylinder . By making a 90 degree pipe with a exhaust flange and coupling it to the stainless flexible joint and it works a treat. The old co2 welding cylinder alows the gas to expand allowing a quieter and quick exit of the gases to the exhaust. it just needs painting hope this helps Tankdriver, Could you take some photos of the modification you did and list the parts you used. regards, Skip Quote Link to comment Share on other sites More sharing options...
tankdiver Posted October 16, 2015 Share Posted October 16, 2015 Has the pictures helped to make a new system?:cool2::cool2::cool2: Quote Link to comment Share on other sites More sharing options...
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