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MG TD TF 1500 - Destroyed distributor
|A couple of days ago I was running along fine in the 1953 TD when it gave a cough and died. No bangs, no rattles: a slight hesitation and then just the sound of the wind in my hair. It had probably done a couple of hundred miles in the last month so it wasn't straight out of its winter rest, and was running very well up to that point.|
To cut a long story short, although it appeared the fuel pump had packed in (and it appears it may still have done so), the distributor had suffered a catastrophic failure. The engine turned over fine but the rotor arm wasn't moving and the inside of the dizzy was completely oaked in oil.
I've dismantled it and found that one of the the timing control weights had become detached and completely mangled and I'll have to get a new distributor. Problem is, I can't seem to get the old distributor housing out. I've withdrawn a tapered(?) bolt - it's a bolt, not the cotter pin shown in the manual (it's short and looks pretty grotty and more stretched than tapered) and this has loosened the dizzy body so it rotates and there a very slight up-and-down movement but the body won't withdraw from the block.
I've scoured the archives for help and looked at the workshop manual but it got me a bit stumped. My engine is no. 24701 which should have the "modified distributor fixing". OK. But I can't work out what "loosening inwards" means (workshop manual again). Any ideas?
The other issues are:
1. Any thoughts on what caused the original problem? It looks like an original dizzy so it might have just had its day.
2. What replacement should I get, which might be available this side of the pond? Are there any substitute models for later MGs that would suit? I don't particularly want to go electronic but, equally, should I be paying the 250 the regular suppliers seem to be charging for a straight TD replacement distributor.
3. Finally, I'm a bit worried that the failure of the rotor arm to rotate when I turned the engine over and the reluctance of the dizzy body to come clear of the block means there might be some stripping of drive gears or distorted bits blocking its removal (or am I worrying too much?)
I'm not very expert at these matters - I'm on a steep learning curve and very happy to earn, so all thoughts would be much appreciated
|Disintegrated weight shown, below. There are half a dozen small bits and the large portion is also badly scored.|
BTW: I hadn't needed to touch the distributor previously so the handiwork with the screwdriver isn't mine. (My late father was always going on about the bloody amateurs who ruined fine engineering - usually by the over-enthusiastic use of a "Birmingham Screwdriver").
|This might be a silly question, but did you actually withdraw the pinch bolt? If not, I seem to remember that there is a groove machined around the body that is partially engaged by the bolt, and might be trapping it in place, but allowing it to rotate. I don't think that there would be anything beyond that to hold it in place. I can understand your concern, since the dist. is driven by the camshaft...my prayers are with you!! Even if you stripped teeth from the drive, I shouldn't think that this would prevent the body and shaft from withdrawing. Let us know what you find. |
|Yes, you do have problems! I have no first-hand experience, but if the shaft does not turn when the engine does you have a sheared drive gear, a sheared pin, a broken distributor shaft or cam shaft (seems unlikely) or a stripped cam gear.|
You can rule out the broken or stripped cam if the rockers move when you turn the engine. Otherwise, the dizzie looks toasted. You may well have to pull the sump and see what is going on, and/or to remove filings and fragments.
If you have the earlier fixing just remove the retaining bolt that screws into the distributor flange. If you have the later fixing, just loosen the retaining nut and the dizzie should pull satraight up. Then remember to remove the clamp! Just grab ahold of the body and pull and twist; there's no other trick to it. You may have to lever off the distributor from the bottom if it is particularly distorted. Much will then be revealed.
I'm confident that there are many distributors floating around second-hand; I believe Moss sells a converted modern one, but why? Over on this side of the pond we have Jeff Schlemmer of Advanced Distributors, who could easily fix you up with a completely rebuilt one with new bushings, re-attached tube, new condensor, point and rotor. I just bought a very nice one for less than a hundred dollars on eBay, but buying one that way is a pig in a poke.
Please let us know what you find.
|As I think about it, I am wrong - you can't rule oput a stripped cam gear by looking at the rockers, which would continue to function normally. And a broken cam might just have enough of a rough break to continue to operate the valves.|
If you have loostened the clamp nut try tapping it a bit to make sure it is free in the groove to allow the distributor tube to pass by, before you pull on the distributor..
|You have to tap the pinch bolt back in. Then pull the distributer. The pinch bolt will pull out then. It has a notch in the side that tightens up to the body of the dist. when you tighten the nut.You may have to try and rotate the pinch bolt a little to clear the groove on the neck of the dist.|
|Thanks for the help yesterday. I turned the engine over with the rockerbox cover off and all the tappets are doing what they should. I then managed to jiggle the distributor free and the drive gear looks undamaged (see pic, below).|
I can't work out why the rotor arm had stopped turning - the distributor shaft is intact - but I'm hoping a clean break on the camshaft wouldn't allow all the tappets to function as they are now(?). The distributor drive on the camshaft is also turning when I blip the starter. Still, a proper look with the sump off is probably now in order.
Question remains about the best replacement distrib. Has anyone got details of makes and model numbers etc? Are there later, more readily available types that I might get more easily (and for a bit less money).
|Tom, by the looks of the dizzy gear I'd say the shaft droped down below the cam gear. That would also explain why you had difficulty removing the dizzy. You had to get the teeth back in line before it would slide up and out. I don't think your going to find anything unusual in the sump. Just my thoughts.|
From your last picture I can see that the distributor drive gear fixing pin has sheared and the gear has dropped out of mesh with the camshaft. you are lucky that the it did not drop into the sump.
What is the part number stamped on the distributor?
Brown & Gammons sell a replacmnet distrubutor with an advance curve adapted to modern petrol but it is expensive also it uses plug in HT leads instead of the screw type.
|Unless the actual dist housing is cracked, I don't know why you couldn't rebuild this distributor? Certainly ought to be more economical and you will then know exactly what you have. You'll need a set of weights and springs, a new shaft? new bushings, a new shear pin for the drive gear...maybe all there is to it.|
|Nice call, LaVerne and John.|
I agree the distributor is rebuildable. I would contact visit the web site and contact Advanced Distributors. http://www.advanceddistributors.com/
They are moving their next week, so you may not get an imediate reply, but even with the shipping back and forth, you will get a good value, and a distributor that functions better than new with a proper advance curve. Just tell them what you are running for a cam and CR, and what fuels you use so they can properly set up the curve.
|Thank you for your reassurance, gentlemen. I couldn't understand why there hadn't been any great grinding or crunching of metal but your thoughts fit with all that. The number on the dizzy is: DKY4A 40058A and then below that A131 (arrow) 945.|
I'd like to stay original spec if I can. The distrib. body is OK so I will e-mail Advanced Distributors and I'll let you know how I get on.
Once again, thank you all for your help, it is very much appreciated.
I thought that somthing was strange about your distributor, it is not for a 53 TD but for a TC the 945 inscription means september 1945. On late TD distributors the cam is a high lift type you have a symmetrical cam.
It could be rebuilt but the problem would be to find a good shaft/plate assembly, all other parts are available. I have a shelf full of weights, toggles, cams springs, bodies no shafts.
|Tom, I don't really see a need to drop the sump. What I would want to see is the condition of the teeth on the cam gear. With a strong light and turning the engine over by hand I'd give it a good inspection and make sure that it hasn't worn with a peculiar pattern or lost the edge of some of the teeth. The dizzy drive gear looks like it's been riding low for some time based on the wear marks on the shaft. Jeff's moving this week but he does excellent work for very reasonable prices. Rebuilt my MGB dizzy and someday I'll send him the one in my TF for a recurve.|
For what its worth, I was having a high speed miss with my TF-1500 and was sure that it was dizzy related. There was a couple of other clues to lead me in that direction. Anyway, I pulled the dizzy and sent it off to Jeff at Advanced Distributors and a couple of days later I got a phone call from Jeff and the first thing that he said was "We gotta talk". Not what I wanted to hear. Anyway, he said that my dizzy had been rebuilt before and that there just wasn't enough left for him to do anything with. The longer that we talked he asked me how I used the car, meaning what kind of driving I was doing, and he said he had an idea. I told him to go for it and what he did was rebuild a 45D he had and adapted my drive gear to it and he sent it back to me. I installed it and that car has never run that good during my custodianship. I've since sent off two more distributers to Jeff. Hope this helps.
Cheers - Dennis
|It's so great to get helpful opinions.|
Yes, you have a TC distributor. To return your car to original, keep your eyes open for one with an appropriate date of mfg. a few months before your car was made. If you let us know the ID number of your car or the date of mfg we will keep our eyes open for you (I may have one).
I also agree with LaVerne that there seems little reason to drop the sump, since there seems no immediate damage to have caused any swarf in the sump. Another dizzie will get you back on the road with no problem.
Jeff can very probably rebuild the body you have, and you might do better to sell that to a TC owner who wants one with the earlier date.
Let me know the date of mfg of your car or the serial number, and I'll see if I have one.
|Laverne: Thanks for the message. I've had a look at the teeth on the cam gear, using a flexible 3-LED light I got a little while back - it's very good at getting into the awkward spots like this - and they seem to be OK. |
John: That's interesting to know - a 1945 TC dizzy? The rebuild the PO did on it in 1978 (it did 1,000 miles in the next 31 years before I got it last year, but it was run [and MOT'd] every year) might account for that, but I suppose it might be earlier. Anyway, assuming it CAN be rebuilt, are there any problems going with it again - or do I get the right model for the car, or get one of Peter Edney's £300 43D replacements?
Decisions, decisions .........
|Tom: I was writing my last reply as yours was being posted. I'd be happy to buy replacement original, if anyone has one. The engine number is: TD2/24701 and it was built in January 1953.|
For 1953 engine you should have the cotter bolt and the distributor is the D2A4. The spacing from the distributor base to the center of the drive gear is different on the D2A4 and the DKY4A. See Bob Grunau's excellent description here:
I've also included photos to show the difference. Here is the D2A4.
|Here is the DKY4A.|
Despite being on the "wrong side of the pond", you might want to consider Advanced Distributors in Minnisota - see:-
£300 is a lot for a rebuild, and Advanced can do a rebuild for a lot less, and will add solid state and modern curves as well.
Just be sure you put a manifest in with your shipment to the US and make a copy for yourself, and get the PO to stamp your copy when you send it off to avoid paying any duty or excise on your distributor, when its returned.
|Gordon A Clark|
Jeff replaced my shaft when he rebuilt it a year ago February, so I surmise he has some on hand.
|I've written Tom Bennett about a spare distributor I have on hand.|
|Once again, thank you all for your helpful comments and particularly to those who researched what the problem might have been, took the trouble to post photos and put me on the right lines. |
I've replied to Tom to say I'd be very happy to take him up on his very kind offer.
All the best,
|I've another small question for the members of the BBS. Sadly, Tom Lange's distributor is beyond repair - and my thanks to Tom for all his efforts in this - but Jeff hasn't currently got a direct replacement. I've now written to him to see what he might still be able to do, although I've got to have one eye on the budget for this as the freight and [particularly] the Customs charges you now have to pay to import these things into the UK makes the costs mount up very quickly. |
Jeff previously suggested that the "Distributor Doctor" over here in the UK might be able to help but he hasn't got a D2A4 of the right type either. Every internet search I've done over the past few weeks has also drawn a blank, other than to throw up the new dizzys (Brown & Gammmons. Peter Edney etc.)
There are however, plently of new Lucas distributors out there - 45D4s, for example, at very reasonable prices (< £60, all in). If I don't go original spec, which one of these might be the best bet, if only to get me back on the road so I can source a D2A4 later on?
|Tom, are there any 25Ds from the early MGBs over there that you could pick up? I would rather have one of those for a temporary setup than a late model 45. Out of the box, the curve might be a little better suited for our older engines. Just a thought. PJ|
|Substitutes can come from A "Mini" or a Honda. I have obtained a Honda that will work but has a vacuum advance on the side. Don't know about the Mini dist.|
There is an article, www.woseley.com.au/flyingw/fast/timing.html
This article gives a bit more info on substitute dist. which you could use till you locate a "proper" dist.
This thread was discussed between 21/04/2010 and 01/06/2010
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