yorkshire_spam Posted July 30, 2021 Share Posted July 30, 2021 I'm a bit stumped and although the fault seems to have gone I'm nervous about it returning as I haven't found a root-cause. A month or so ago I got the Spitfire back on the road and started running in the new engine. But over time I found the ignition was too far advanced giving me pinging even under moderate load. I re-timed everything on the assumption that either I'd done the timing wrong in the first place OR that things were just "bedding in". After a week or so of running I checked it again and this time it's way to far retarded, so I re-timed again. Then the other night it was so far out that the mis-fire stopped me in my tracks, "twiddling" with the dizzy position got it running well enough to get me home. I've gone back to my old dizzy now just to be on the safe side. I pulled the water pump and took the timing cover off to check that the vernier gear on the cam hadn't moved - still where it should be and no signs of movement (all the bolts re-tightened and thread lock applied) I've inspected the recon dizzy I removed and I can't find anything wrong with it, because of the engine spec there's no vac advance and the base-plate is firmly locked in place. The bob-weights seem to move freely as expected. The recon company have (very kindly!) agreed to re-inspect the dizzy if I send it back to them - so at some point I'll do that. Dizzy cap is locking firmly in place with no slop/movement when clamped down. I'm out of ideas if the cam timing isn't moving and everything in the dizzy seems to be behaving I can't see how my timing is all over the place. Oh and I've see the same "jumps" and "moves" in the timing on both points AND electronic points replacements. Quote Link to comment Share on other sites More sharing options...
Dannyb Posted July 30, 2021 Share Posted July 30, 2021 I had a that sort of thing on my Spit 1500. I could see the timing moving all over the place on tick over with the timing light. I think mine was due to the faulty ballast wire which was only putting out 4 volts. I bypassed it with a 12v supply and a new 12v coil. Since then it has been on a rolling road tune-up. Danny 1 Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted July 30, 2021 Author Share Posted July 30, 2021 Thanks Danny, I'll do some voltage checks. The timing seems stable at tick over (if I get it set up for a clean not lumpy tick over) but just seems to move over time. Quote Link to comment Share on other sites More sharing options...
sparky_spit Posted July 30, 2021 Share Posted July 30, 2021 Are you sure that the front pulley is not slipping round on its rubber damper, so that you are actually setting the timing incorrectly? Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted July 30, 2021 Author Share Posted July 30, 2021 20 minutes ago, sparky_spit said: Are you sure that the front pulley is not slipping round on its rubber damper, so that you are actually setting the timing incorrectly? No rubber damper on the 1500 - the pulley is keyed directly to the crank. But keep the ideas coming, cos I'm completely stuck! Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted July 30, 2021 Share Posted July 30, 2021 I had something very similar on my PI and that was definitely the mechanical advance in the distributor sticking. To make it harder to find, it only did it when hot. It was actually the upper shaft (with the points cam on it) going tight on the lower shaft rather than the actual weights sticking. Nick Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted July 30, 2021 Author Share Posted July 30, 2021 4 minutes ago, Nick Jones said: I had something very similar on my PI and that was definitely the mechanical advance in the distributor sticking. To make it harder to find, it only did it when hot. It was actually the upper shaft (with the points cam on it) going tight on the lower shaft rather than the actual weights sticking. Nick Very interesting, thanks Nick, I guess if I don't see the issue on the Border Raiders then there is a fair probability it was the recon dizzy. Quote Link to comment Share on other sites More sharing options...
RobPearce Posted August 9, 2021 Share Posted August 9, 2021 On 30/07/2021 at 15:31, Nick Jones said: I had something very similar on my PI and that was definitely the mechanical advance in the distributor sticking. I had (possibly still have!) the same on my 1500-engined Mk3, albeit with a Delco disi. Quote Link to comment Share on other sites More sharing options...
Guppy916 Posted August 9, 2021 Share Posted August 9, 2021 I had Lee at H&H referb my delco dizzy, he popped a little brown box inside so no more points, it's blinking fantastic now have a look https://h-h-ignitionsolutions.co.uk Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted August 9, 2021 Author Share Posted August 9, 2021 My dizzy was rebuilt by H&H they've kindly offered to take it back and test it for me - when I get chance I'll post it back to them. Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted August 10, 2021 Share Posted August 10, 2021 HI Sam, how did it perform on the Border Raiders event? Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted August 10, 2021 Author Share Posted August 10, 2021 21 minutes ago, Tim Bancroft said: HI Sam, how did it perform on the Border Raiders event? No ignition issues during the run Tim, which leads me to think the recon dizzy is the issue. What do you think @Clive was our Spitfire going OK on the Border Raiders? Quote Link to comment Share on other sites More sharing options...
Clive Posted August 10, 2021 Share Posted August 10, 2021 20 minutes ago, yorkshire_spam said: No ignition issues during the run Tim, which leads me to think the recon dizzy is the issue. What do you think @Clive was our Spitfire going OK on the Border Raiders? It seemed to be scooting along very nicely indeed. Plus you were excellent at "pothole spotting"! 1 Quote Link to comment Share on other sites More sharing options...
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