I really don't want to take this out again. So as I mentioned last time I thought I may be able to sort it while still in the dash.

Reaching around the back again I was able to loosen the two knurled nuts so the gauge came forward about 5mm.
It was a bit of a struggle but the bezel and the glass came off and I undid what I did to the needle the other day. ie. unhooked it from the stop and let the needle go back around.
It wouldn't go back to zero unless I flicked it or pushed it back. Generally it would sit at about 30kph.
Using the two tea spoon trick that someone mentioned, I popped off the needle and moved it around so it was pretty well at zero when it sort of centralised.
Took it for a drive and stopped and started and fiddled about and I think I ended up with it as it was before - sort of accurate but very sluggish and won't go back below about 30kph.
I think I know what the issue is and it's my fault . We have to go back a few years to when I took it apart before. At that time I cleaned off all the old dried grease and rather than not have any lubricant I used what i had and put a little petroleum jelly on the moving parts.
This I think was a big mistake as this is too thick and offers too much resistance to the movement of the needle.
To fix this properly I have to strip it down again, clean that off and use something a lot lighter to lubricate.
But that is for later, when I forget what a bear it is to take out and put back in.
So a bit of fiddling got the glass and the bezel back on and I tightened the nuts back up.

One other thing I want to do is change the knurled nuts for the speedo. They work ok for the tacho but a different design for the speedo would make it easier, especially because of the earth leads which are attached here as well.

Something like this:

Went to Docs and gym this morning and when I came home I was sitting in the car and started thinking about and looking at the two gauges in front of me.

Next thing I know I'm sitting there with the tacho in my hands and thinking 'well that was easy'.

Popped off the bezel and the glass - again easy! Then pondered on how the innards came out. Took it inside and used a kitchen knife to pry out the surround with the rubber in it and could see that only 2 screws where holding the guts in there.

Screwdriver made short work of that and I'm studying the innards. Don't think I'd had this apart before.


Well the trim pot is very obvious, it's that black thing at the top:


It looked like it would be easy to hook the innards back up in the car and attempt to adjust with the other gauge as a control. When I first hooked it back up it wouldn't work! Then it dawned on me that it needed an earth. So I found a short lead with an eye on it and attached it to one of the screws that I'd removed to take the innards out. That's the green wire here:


The engine analyser was attached to the motor and sat just in front of the windscreen:


Then with a screwdriver while juggling the throttle to get steady revs via the analyser, I was able to adjust the trimpot to match the tachos reading to the analysers:


Pretty easy actually and I checked it at a few different readings 1000, 2000 and briefly at 4000.

Put the tacho back together carefully and thought about the speedo.

Decided to take it out and have a go at that. Long story short - couldn't remember how it came apart because of the trip meter stalk.
Well, I posed the question on the forum but because of the time difference of most of the members, got no answer. So had a brain snap and wound the needle around and hooked it over the stop again. Bone head move as it turns out because now there way too much tension on the needle and it won't move at all on a test run.
I also had the devil of a time getting it back in - tacho went in reasonably easily. Still a bugger but the speedo is a real turd!

Anyway this evening after a failed test run on speedo (tacho appears to work well) I checked the forum post and did some extensive searches and it appears that the needle and the face of the gauge has to come off. I don't remember having to do that - but I must've.
Anyway that's the plan. I may be able to do it without removing the gauge completely. If I undo what I did today with the needle I may be able to take the needle off, run it with a temporary needle made from a small piece of masking tape and take note of where it is pointing at , say 70kph using the GPS and then come home and work out where the needle needs to go accordingly.

We'll see tomorrow. Stay tuned.

I've put up with a dogey speedo since I put it back on the road but now that the OD is functioning well the cars ability at speed is now an issue.
As well as that it's become obvious that the Tacho is grossly overstating the rpms of the motor. I'd always struggled to get it to idle at a suitable speed by the tacho and now it seems that the tacho was giving me the wrong readings.

I have an engine analyser that does dwell, amps, volts and rpms that I've had for ages - I made mention of it when I checked the action of the OD solenoid.
I'd always thought that is was giving me bad readings and for some reason I had trusted the cars Tacho over it.

When I mentioned in a post on the forum the different rpms with and without OD in 4th. Several members questioned the readings and I went back and hooked up the meter and if I assume the meter is reasonably accurate then the tacho is way out.

At 2k on the meter the tacho reads over 3k and at 4k on the meter the tacho is redlining. No way it's revving that fast!

So the tacho has to come out and I've got a few links to data on how to rehab and adjust it.
While I'm there I'll do the speedo as well. When I pulled the speedo apart before I don't think I put enough preload on the needle and it's slow to return to zero - in fact it doesn't go back lower than about 30 kph.
It's pretty accurate after that on the way up but is very slow to return on the way back. I think I can fix that.
I don't really need it to be that accurate, I just need it to give a good sweep from zero up and back again.
The numbers are an overlay that I did and that can be adjusted to suit what I end up with.

That is the next plan. I'm just not looking forward to delving up into the scarey recesses of the 'dark side of the dash'.

Having finished off the clutch re-visit, I've been enjoying the exploration of the OD. After the initial shake-down mentioned in the previous entry I was keen to give it a good decent run.
So after checking on eBay and finding nothing, I gave Heritage motors a ring to enquire about a OD speedo cable.
After some discussion on the phone it was established that they had one there and they would send it up to me.
"Hang on, I might take a ride down and get it." Ok, they will leave it on the counter waiting for me. If I change my mind give them a ring and we'll send it out.

Ok. Sounds like a plan. A good freeway run. Never taken the MGB that far into the city before.
So I set off. Top of the hill, just before the expressway, I stopped to fill up and I was a little worried 'cause it wasn't running real good - nothing major - just didn't feel right. So I filled it with unleaded without ethanol. Normally I just run on E10.
Pulled over to check the tyres as well and popped the bonnet just to look at everything. Absentmindedly I reached in to check the plug leads.

Hang on! This plug's loose! WTF they're ALL loose.
Then it dawned on me. I'd taken the plugs out to turn the motor over for some reason that escapes me now and I remember just putting them back just to fill up the hole and thinking I'll tighten them later.
Well, I never did. What a bone-head! That could have been nasty.

Anyway I had a old plug spanner with me so I was able to pull them out, check them and tighten them back in. What a dingbat!

Any way after that it ran a lot better and I went down to Smithfield and back without a hitch.

Next day I put the cable it and all is well. The speedo is still not reading correctly but it is the same as it was before.

I'll have another go at sorting that out another day. It doesn't go all the way to zero. I believe that when I pulled it down a few years ago I didn't put enough tension on the spring inside.
I think it would be a simple matter to pull it down again and change that.

Started this morning and checked that the bolts would go in beside the U joints. Yes! Easy-ish!

So to drill the holes to couple it together.
I was anticipating this to be more difficult than it was so I've gone a bit overboard with the photos. So because I took them you have to look at them!

I thought that I was in for a long fiddly process of measuring and drilling the holes 'cause I wanted to sure they were accurate. Well hit on a short cut using an old valve stem that happened to be the exact size - 5/16". So holding it in a cordless power drill and resting against my bench grinder, I was able to accurately grind it to a point to act as a centre punch as shown in the series of pics below.

Close up of ground tip.

How it was set up to use.

The resulting punch mark. Probably more accurate than I could measure, mark out and then punch.

Then a 1/8" pilot hole. Allowed the the centre punch mark to do the precise alignment of the drill, holding it loosely so it can move to the exact place then holding it tightly. Only works with small drills.

Then using the drill bit to position, I clamped it in position for the next two drills - 19/64" and then 5/16" without moving the setup.

And the 5/16".


Using a short bolt to locate, the opposite one is marked and drilled the same way.

Using 2 bolts to positively locate, the other two positions are marked.

And the second one.


The two remaining punch marks are shown here.


After drilling I used a hand drill to slightly countersink the holes front and back.


And here's the finished piece from both sides.



Well I was ready to go! Well, no! In practice the holes were just a little snug so I ended up taking them out to 21/64" and they went together quite easily under the car.

The only other thing I had to do was deal with a missing screw retaining the speedo input. I couldn't find the screw. I don't remember taking it out so I'm thinking it wasn't there in the first place. I just wanted something to make sure the spindle wasn't going to fall out. So I found a bolt that fit 5/16" UNC apparently and ground a little spigot on the end and put it in with a bit of locktite. When I get my new speedo cable I'll sort it out properly.

Well that's it - so it's time for a test drive.

Again long story short - YES YES YES! Smooth clutch AND functioning OD.



Works great on the way up. Haven't mastered it on the way down. Remember I haven't got the vacuum switch. So in the meantime I'm clutching on the way down.

It's another good MGB day. Can't wait 'till I can give it a good test drive.

Did this on Friday - haven't had a chance to write it up 'till now.

Annoyed at myself for not taking more photos, especially of the block I started with.
Made more frustrating because the times I thought of taking pics I didn't have my camera with me, I'd completely forgotten about my new phone which has a decent camera in it and this was in my pocket the whole time! In fact the 3 pics I have I took with it. They're not great but certainly acceptable.

Well, continuing on, I needed a slug of steel about 86 x 30 and when I went to the steel merchants in the morning - I had to wait for them to open at 7.30am - the closest they thought they had was 90mm dia. Perfect! However, in reality they couldn't find that size in the yard so I went with 100mm dia x40mm. Just a 'bit' more turning. Cost me $15. Sort of a min charge, he reckons he actually gave me a 47% discount. Yeah right!

Still, not too bad.

Went to school to check that I was able to use the lathe and then went to the gym then home to do some 'housework'.
Went back in and spent a couple of hours and came up with this.
This is the side that the shaft attaches to:
I set this up in a 4 jaw independent chuck with the jaws reversed. The recess is a lot deeper than required but I did that so I'd have plenty to grip on the outside of the 3 jaw chuck jaws. (the reverse jaws of the 3 jaw had been lost many years ago.)


This is the side which goes to the box. I would have liked to have bored the centre right out but I didn't have time and I couldn't find a boring bar. Same with the large groove around the centre. It's a bit heavy.


This shot shows the spare flange on the adapter. The ring around the outside about 5mm up is simply a machining mark where i'd changed the angle of the tool. It's only visible and you can't feel it.


After this I took it to my bolts supplier to see about the studs before I drilled for those. Well, long story short, no studs available without special order or me modifying bolts. So I got 4 long bolts and I'll check if I can get them in the drive shaft flange before I simply drill the adapter 5/16".
I suppose that's the easiest and quickest anyway.

Stay tuned for that.