earckens Posted April 23 Report Posted April 23 My TR4 has the classic ignition points. What is the suggested mileage maintenance interval, and what is the recommend gap distance? I guess it must be measured at top-dead-center if I am not mistaken.... please correct if wrong? Quote
BlueTR3A-5EKT Posted April 23 Report Posted April 23 Standard Lucas TR4.distributor. points gap 0.014-0.016”. (I used to aim for 0.015”). This is adjusted and set at their maximum opening Engine TDC has nothing to do with dictating this It is the position at which the distributor points cam opens the points to their maximum. Service interval 3000 miles. Clean, inspection, reset gap or renew. Quote
BlueTR3A-5EKT Posted April 23 Report Posted April 23 Erik Here is a photo of the Lucas service page from a Standard 8/10 manual. Same distributor type as TR4 so relevant to your car. They say lubricate at 3000 and clean/inspect/reset at 6000. Quote
iain Posted May 6 Report Posted May 6 On 4/23/2026 at 4:34 PM, BlueTR3A-5EKT said: Standard Lucas TR4.distributor. points gap 0.014-0.016”. (I used to aim for 0.015”). This is adjusted and set at their maximum opening Engine TDC has nothing to do with dictating this It is the position at which the distributor points cam opens the points to their maximum. Service interval 3000 miles. Clean, inspection, reset gap or renew. Agree with Peter. If you’re using quality components, they last for 10000 miles plus. I had my distributor rebuilt some years ago by Martin, Distributor Doctor, and always use his spares. Iain Quote
earckens Posted May 23 Author Report Posted May 23 Just now I checked the gaps on my distributor (there are two sets of points, opposite of each other). I can get a 0,0013 spacer between the points at their widest. But I have a tight fit. When loosening the adjustment screw I can squeeze open the points, then I fit the 0.0013 spacer and let the spring tighten the points again. Then I tighten the adjustment screw and remove the spacer. Is that the correct procedure? ...because I can insert the spaver after that, but still a tight fit. My next spacer is a 0.020". Or I can combine a 0.013" + a 0.00315" spacer (to get 0.016")? Quote
stuart Posted May 23 Report Posted May 23 9 minutes ago, earckens said: Or I can combine a 0.013" + a 0.00315" spacer (to get 0.016")? Thats the gap you should be aiming for. Stuart. Quote
trchris Posted May 23 Report Posted May 23 Well I’m confused about two sets of points ? However you only need to loosen the retaining screw slightly so the points cannot move until using a screw driver, adjust to desired gap and do up the screw checking gap afterwards Chris Quote
earckens Posted May 23 Author Report Posted May 23 (edited) 25 minutes ago, trchris said: Well I’m confused about two sets of points ? However you only need to loosen the retaining screw slightly so the points cannot move until using a screw driver, adjust to desired gap and do up the screw checking gap afterwards Chris The distributor has two sets of points, opposite the rotator. I have forgotten what its purpose is, I may find out by tracing the wiring. But I now did set the points at 0.016" (two spacers, 0.013" and 0.00315" conbined). They were too close (I guess, like 0.012"), but I have driven the car like that for several years; I guess it will now run even better :). Edited May 23 by earckens spelling Quote
earckens Posted May 23 Author Report Posted May 23 28 minutes ago, stuart said: Thats the gap you should be aiming for. Stuart. Thanks Stuart, that is what I did now. Quote
RobH Posted May 23 Report Posted May 23 (edited) The gap you quoted is for a Lucas distributor and suits the shape of the cam used by Lucas. Is your dizzy a Mallory? If so the cam is a different shape and I have seen a figure of .022 - .024 inches quoted for those and the setting process is rather more complicated: https://www.jalopyjournal.com/forum/threads/ignition-tech-proper-method-to-set-gap-on-a-dual-point-distributor.459917/ https://www.mgexp.com/forum/mgb-and-gt-forum.1/mallory-dual-point-dwell-and-gap.1577952/ Edited May 23 by RobH Quote
earckens Posted May 23 Author Report Posted May 23 @RobH well I am not sure, tomorrow I post a picture of my distributor. But in any case the setting for this dual point distributor is more complicated than I imagined. Thank you RobH. I am sorry to all of you here for not having been unambiguous in my OP. Quote
earckens Posted May 23 Author Report Posted May 23 Why wait for tomorrow? It is a Mallory distributor. Stupid question: does the distributor turn clockwise or anticlockwise. Quote
RogerH Posted May 23 Report Posted May 23 Hi Erik why oh why have you got a mallory dizzy??? Roger Quote
RobH Posted May 23 Report Posted May 23 (edited) The direction is set by the drive gear so it is anti-clockwise the same as the Lucas ones. Mallory have a reputation for very good quality and the dual-points should give very long service between adjustments. You can see from that photo that the cam is rather different shape from the Lucas one - more of a circle with flats on it. Edited May 23 by RobH Quote
earckens Posted May 23 Author Report Posted May 23 9 minutes ago, RobH said: The direction is set by the drive gear so it is anti-clockwise the same as the Lucas ones. Mallory have a reputation for very good quality and the dual-points should give very long service between adjustments. You can see from that photo that the cam is rather different shape from the Lucas one - more of a circle with flats on it. Thank you @RobH 💗 I still have the machined shank to push out the bushings from the front wheel suspension assembly you sent me some five or six years ago for which I am forever grateful 👍. Quote
earckens Posted May 23 Author Report Posted May 23 14 minutes ago, RogerH said: Hi Erik why oh why have you got a mallory dizzy??? Roger ...because it came fitted to the car when I bought it 😉 Quote
trchris Posted May 23 Report Posted May 23 Ok l understand now the last time l adjusted dual points l used a dwell meter, unfortunately that was back in the 70s on a v8 rover unless you have a dwell meter it’s going to be trial and error until you get it about right Chris Quote
earckens Posted May 24 Author Report Posted May 24 @trchris I do have a dwell meter, so I will get it to work here. But if I understand correctly from the two links shared by RobH here above, measuring dwell is subordinated to setting the points correctly? Meaning, the Mallory distributor has a built-in dwell that cannot be adjusted by much? Quote
trchris Posted May 24 Report Posted May 24 Hi Erik by setting the points gap you are adjusting the dwell , it’s the time the points are closed so if you know what the dwell angle for that distributor is that’s the method I’d use and it was always recommended to check after fitting new points ( back in the day) Chris Quote
earckens Posted May 24 Author Report Posted May 24 6 minutes ago, trchris said: Hi Erik by setting the points gap you are adjusting the dwell , it’s the time the points are closed so if you know what the dwell angle for that distributor is that’s the method I’d use and it was always recommended to check after fitting new points ( back in the day) Chris Thank you for that update trchris! Will be done, it has been many years, but good to dive back into this part of my car :). Quote
Ralph Whitaker Posted May 25 Report Posted May 25 What is the point (no pun intended) of a dizzy with 2 sets. Only time I have seen a set up like this was on old twin cylinder motorcycles. Ralph Quote
RobH Posted May 25 Report Posted May 25 25 minutes ago, Ralph Whitaker said: What is the point (no pun intended) of a dizzy with 2 sets. https://mgaguru.com/mgtech/ignition/ig200.htm Quote
trchris Posted May 25 Report Posted May 25 Rover v8 had them before the later electronic system Chris Quote
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