Nilfisken Posted May 4, 2012 Share Posted May 4, 2012 Hi,just a quick check here. Tomorrow I plan to replace my old distributor with a brand new one, same type (45 D4) and just like before electronic ignition. Reason for change is that the old one has quite some play in it and one of the screws attaching the electronic unit to the baseplate has its thread stripped by a previous owner. I found a new one cheap on ebay and decided to give it a go since my rev counter can occasionally show weird readings under hard acceleration (electronic rev counter) and the timing can sometimes flicker quite badly so maybe a more solid dizzy would be a good idea.Anyway, on to the question :)Is there anything to watch out for while doing this swap? As far as I can understand the drive dog can only fit in one position so it should be more or less technically impossible to get it wrong? I guess that if I check the position of the distributor cap relative to the engine, lift the distributor out and fit the new one without rotating the engine and position it so that the cap roughly sits like the old one the timing should be close enough so that I can start the car and set it properly.Any good hints on the way that Mr. Haynes and his friends forget to tell me about?Cheers! Link to comment Share on other sites More sharing options...
junkuser Posted May 4, 2012 Share Posted May 4, 2012 "if I check the position of the distributor cap" It is the position of the rotor that should be the same to engage the drive correctly, the position of the cap is best approximately the same and then adjust to get the correct timing. Link to comment Share on other sites More sharing options...
Nilfisken Posted May 4, 2012 Author Share Posted May 4, 2012 But if the engine is not turned over I guess it is impossible to get the rotor wrong since the slot in the drive dog appears offset so it will only go in one way? Link to comment Share on other sites More sharing options...
junkuser Posted May 5, 2012 Share Posted May 5, 2012 Sorry if I misunderstood your post.As you say it should not be possible to get the drive in the wrong way around but it is amazing what some people can achieve. Link to comment Share on other sites More sharing options...
Nilfisken Posted May 5, 2012 Author Share Posted May 5, 2012 Then we hope for the best! Reading in the manuals how it supposed to be done it sound so easy it is too good to be true. Last time I changed a distributor was in a Chevrolet 350 cui and in those it is possible to get the distributor back in almost any firing position. The Triumph system seems so simple you wonder if there is a hitch somewhere :) I report back tomorrow and let you know how it went! Link to comment Share on other sites More sharing options...
junkuser Posted May 5, 2012 Share Posted May 5, 2012 Just plonk the distributor in with the rotor in a similar position to the one you took out and turn the rotor a little in each direction till the distributor drops fully down.Fairly foolproof. Link to comment Share on other sites More sharing options...
nang Posted May 5, 2012 Share Posted May 5, 2012 Suggest you make sure the model numbers are the same or the advance curve may be wrong for your engine.Tony. Link to comment Share on other sites More sharing options...
Nilfisken Posted May 5, 2012 Author Share Posted May 5, 2012 Good point but unfortunately the new distributor is an aftermarket sold as 'Spitfire distributor' and cant find any numbers at all on it :( I will install it and then listen carefully for pinging issues, the current distributor can occasionally given pinging in third gear on acceleration even if the timing is set at the suggested 10 BTDC. I don't even know if the one used now is the correct one.Cheers Link to comment Share on other sites More sharing options...
Nilfisken Posted May 5, 2012 Author Share Posted May 5, 2012 OK, distributor changed, no more pinging issues but feels like a tiny bit of torque is gone in the lower rev regions. Nothing serious at all more that you have to downshift a bit more in town. I was planning to move the advance unit over between the two to make them as identical as possible but the top part of the shaft is screwed down on the replacement but fixed by some odd plastic bushing in the old one. If we could only get some decent weather I plan to take the car for a decent spin to find out if fuel economy is similar, if so I will keep the new one for now since I can rev the car properly under acceleration with no pinging at all. Link to comment Share on other sites More sharing options...
Nilfisken Posted May 5, 2012 Author Share Posted May 5, 2012 Btw, the old unit had the part number 41449 that should mean it is original and also had a manufacture code saying 50 week of 1977 which make sense for a 1978 Spit :) Link to comment Share on other sites More sharing options...
junkuser Posted May 5, 2012 Share Posted May 5, 2012 Have you tried advancing the timing till the pinking returns to where it occurred with the old one to compare the low down torque?If the fly weights are of the same design you may try swapping the springs.Not sure if you could swap the whole flyweight mechanism. Link to comment Share on other sites More sharing options...
Nilfisken Posted May 5, 2012 Author Share Posted May 5, 2012 Good point, I wil try that after I had a first long drive with the new one to see the economy aspect. Wont be able to swap the whole mechanical advance unit since the new one had a screw in top part of the main shaft (the part that has the advance cam), while the old one has a weird plastic bush at the top. Might work if the plastic is removed but I'm worried about damaging it since I still want to have it as a backup while trying out the new one. Changing springs should be easy though!Cheers! Link to comment Share on other sites More sharing options...
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