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TR2/3/3A Remove and replace distributor in TR3

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M

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Can anyone give me, or direct me to, instructions on how to remove and replace the distributor on a TR3. I want to send mine off to Jeff for a rebuild, but I will have to remove it myself.... and replace it when it has been rebuilt.

Your help, as usual, is much appreciated.
 
Not much to it as I recall -- just undoing 2 nuts (1/2"?) that hold the plate that also forms the clamp. Then just lift it out.

Of course you'll have removed the distributor cap w/wires & vacuum line beforehand.

Since (I assume) the car isn't going anywhere until the unit comes back -- you might find it simpler later if you move the engine to TDC for #1 ignition (rotor more or less pointing at #1 spark plug). Having it there may make for less thinking when reassembling.

Stuff a rag or something in the hole left behind so nothing gets dropped in there.

Once you have it out take a look at the drive dog (the bottom of the unit that engages the shaft still in the engine) and notice that it is slightly asymetrical... i.e. the cross pin is not centered. This allows the thing to be reinserted only one way.

You may want to find out how much Jeff wants -- i.e. do you remove the clamp, rotor, points etc. Even if you go with Pertronix you will still want a set of points for a spare.

Chapter 4 section 6 of the Haynes... page 98, in my edition.
 
Hi, George,

Many thanks... I can count on you for good advice.

Your are right: the car won't be going anywhere until the unit comes back.

And thanks for the lead to Haynes.
 
Take a few pictures both with and without the cap. It will help with the orientation of the distributor when you go to put it back in.
 
As Geo said not much to it. You can remove by just loosening the horizontal jam nut and lifting straight up. Mark the position or take a picture before removing to refresh your memory when installing back. When you put it back in, rotate the shaft until it drops into place on the keyway, The keyway is offset to match the distr shaft key. Will only fit one way.

Marv
 
Don,

Yep, I have several manuals, but I find that it is best to ask the BCF crowd before attempting these projects because the by-the-numbers approach of the manuals is good, but experience speaking is much better.

Marv,

I'm curious about all the emphasis on "marking the position" and "taking a photo" to make sure the dizzy is put back properly. Seems to me that if I leave the distributor clamp untouched, as Haynes recommends, that the dizzy will go on just as it came off without disturbing the timing. But, I assume that no matter what I do with the dizzy, I would have to recheck and probably reset the timing when I install the rebuilt distributor.

BTW. When I opened my old distributor, I found that the springs were so rusted that they were rock solid, without any flexing at all. At first I thought I would just replace them with MOSS replacements, but when the new springs arrived they were (a) not the same size as the existing ones, (b) end hooks were in the wrong configuration (on the same plane rather than 90 degrees to eachother). I called around and discovered that the springs I need are "the Holy Grail" of distributor parts -- no longer available. Jeff says he makes his own, but doesn't sell them to customers. I have ended up twistng the ends of the MOSS springs slightly to get the 90 degree position, which changes the tension some but this can be compensated for when resetting the timing. Has anyone else dealt with this problem?
 
Even if you leave the clamp on the distributor, the clamp itself is slotted slightly where it attaches to the engine - so you will definitely need to retime the engine when you put it back on. Like Marvin suggested, it can be easier to just loosen the horizontal bolt and pull it out that way since you are going to have to retime anyway.
 
LexTR3, I always recommend taking a few photos before taking things apart. I don't know how old you are but I'm going on Medicare next month. A picture shortens the length of my ---hummm how was that before I took it apart--- time considerably. Ernie
 
tdskip,

Yes, I use the Advance Timing Light to tune my car. It's easy... but I have been getting inconsistent readings because the springs in my distributor have had no effect. I hope that when new springs are installed, it will work better.... and later I plan to have the entire distributor rebuilt.

Ernie,

Ha, ha... you are a youngster! I have been on Medicare for some years. I agree that taking photos of work in progress is a good idea. I photograph everything I do on my car. But I was just wondering why marking and photographing is so important for replacing the distributor. (I don't doubt it... I'm just trying to understand what's going on).
 
While it is not imperitive that you do this, it will help you to reinstall your distributor back into a position that will get the motor started and then timed with your light. More important if the clamp is left on the motor or removed during rebuild.
 
Got it... Looks like even if I leave the clamp on, reinstalling the distributor is going to require some fine tuning of the timing. That doesn't surprize me, and it doesn't appear to be a problem.

Any thoughts on the "Holy Grail" springs? I'm very surprized that neither the Roadster Factory or Moss no longer carry these springs, and that the ones Moss carries are not correct for the TR3 distributor.
 
If you want to replace springs without a full rebuild you might get some success ordering from the UK. For example, Martin Jay, aka The Distributor Doctor, might be a good place to start: Advance springs

Other than the call to the UK the postage would be really low.
 
Just how hard is it to find an "Auto Electric" shop these days? Used to be there was one in at least every large town; there was even one in Rensselaer, IN (where I went to high school, population about 5000). They would have a cabinet full of springs, and a distributor tester to see if the chosen springs gave the desired curve.

There's an old distributor machine in my shed, but it is probably going to stay there until I manage to retire.
 
Randall,

The problem with finding springs at a local auto shop is that all the new springs have hooked ends that are in the same plane.

-- /////// --

This is right for a plate with two posts.

But my distributor has a post on the plate and a tab on the weight with a slot (as shown in the Moss catalog pictures). That requires a spring with hooked ends that are 90 degrees to eachother (one sideways and one up).

(
-- ////// --

If one hook is not 90 degrees to the other, the entire spring has to be twisted around for the hooks to hold the slot (in one plane) and the post (in the other plane), and the tension thus created flips the hook up and off the post.

It's this older spring with hooks at 90 degrees to eachother that people apparently are calling the "Holy Grail" of distributor parts.

As I said earlier, I bent the hooks of the springs that Moss sent me, but I don't know how they will work.
 
Timing gun on a Triumph? Quit using one 25 years ago. They work well on American stuff and will get you in the ballpark on a LBC but set it by ear. You will be able to tell the "sweet" spot. May take a few tries but found it to work out better.

Marv
 
We already had that argument, Marv. I'm on your side, but Ed insists on using a light.

Bending the springs is exactly the sort of thing a shop would do, but of course both the length and spring constant are critical to getting the right advance curve. That's why the machine is needed, to measure the resulting curve and see if the springs are right. You can do pretty much the same test on the car, but you need either a timing wheel or a light that will compute advance to do an accurate check.
 
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