Marmalade the IIa

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Originally Posted by 1950landy

Some times if you give the horn a couple of thumps on a block of wood the jar will make it work. I ended up fitting a relay for the horn feed because it wouldn't work if I let it sit for a while , seams to work all the time now.

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I’ll give that a go.
If that’s the case I’ll need to keep a rubber mallet at all times to give it a whack!

It seems fitting a relay is the way to go.

The horn ring collar that sits behind the steering wheel has a brass contact that runs on the side of the steering column. That seems to break off easily

by tapping the steering wheel you force the collar down and the small rivets that hood the connector come into contact with the steering column. That works for a while

They wear really quickly, hence once you start bashing you have to keep going!

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Originally Posted by Cadas

The horn ring collar that sits behind the steering wheel has a brass contact that runs on the side of the steering column. That seems to break off easily

by tapping the steering wheel you force the collar down and the small rivets that hood the connector come into contact with the steering column. That works for a while

They wear really quickly, hence once you start bashing you have to keep going!

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I suspect it’s the horn itself that is dodgy, as when I hook a little light instead of the horn it lights up when the horn push button is depressed.

Haven’t had a good look at the horn itself, so not sure if they can be taken apart and what not.

Cheers
Luca

From memory, they can be taken apart, but most are rivetted together, so a little enterprise may be needed. One possibility is that the horn is filled with dust or mud, and you may be able to clean it out with a combination of a wire coathanger and compressed air.

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Originally Posted by Ypsilophora

I suspect it’s the horn itself that is dodgy, as when I hook a little light instead of the horn it lights up when the horn push button is depressed.

Haven’t had a good look at the horn itself, so not sure if they can be taken apart and what not.

Cheers
Luca

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You could try pulling it apart as well, could be as simple as dirty contacts or mud wasp debris…the original 2a horn has a nice note so it’s worth persevering with. My 2a one was similarly faulty, so I thought “what have I got to lose, I can’t break it when it’s already broke”. This video was helpful in dismantling it etc How to repair your MGB horn - YouTube

Cheers, Matt

John, Matt,
Thanks heaps for getting back to me. Tomorrow’s job is the horn!

Stripped and rebuilt the ignition switch, still doesn’t seem to work, which is odd as the contacts were fine once cleaned, although possibly a little worn - might see if I can make a new copper contact with a local engineer/Landy nut who would probably be happy to help.
Doesn’t give full connectivity on glow plug terminal, and when running a 9v battery through it, I only get 7.6v instead of 8.2 through the other terminals (battery wasn’t fully charged).

Rebuilt the foot switch.
As you suggested Matt, just super grotty connections.
Only issue is the tabs crumbled off due to age/galvanic corrosion. So now the face pops out occasionally. DOH!

Earthing issue fixed - thanks heaps John!

Now the earthing issue is fixed, and the ignition wiring mostly works (minus glow plugs), the engine fires!

But, doesn’t idle well, either dies straight away or coughs along for a bit. I’ll try to add a video. Might help with diagnosis.

I suspect either poorly primed fuel lines or poor timing. Other issue is it sort of sounds like there is air puffing somewhere (can’t really here it when running, but when I had my earthing issue earlier you could hear it due to slower tic over - ie less other noises). Sounds like it’s coming from the right hand side of the engine bay, around the fuel pump/air filter, but the sound could be getting ‘lost’


Edit: can’t work out how to upload a video, will try again tomorrow

Okay, turns out the tappets had loosed themselves off, this was (I'm assuming) causing the 'chuffing' noise, the engine is also running much much quieter now.
it still seems to lack power, under load it sounds more like other 2.25d do at idle, and at idle it sounds terrible; very very rough - like its only just above a stall.

could be timing?

Could be timing, but I would also confirm that compression is even (turn over with crank handle if you don't have a compression gauge), and check for leaks in the intake system - vacuum advance piping, PCV valve if fitted, manifold to head join (put some oil on the join), under carbie. Also check ignition wiring and in the distributor consider the points and also the possibility of the capacitor being faulty.

And then there are carburetor settings!

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Originally Posted by JDNSW

I would also confirm that compression is even (turn over with crank handle if you don't have a compression gauge), and check for leaks in the intake system - vacuum advance piping, PCV valve if fitted, manifold to head join (put some oil on the join), under carbie. Also check ignition wiring and in the distributor consider the points and also the possibility of the capacitor being faulty.

And then there are carburetor settings!

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Compression may be a little low on one of the cylinders, it's a diesel, so bloody hard to crank by hand - but on one rotation it seems slightly easier.
I've replaced stem seals, bearings and rings. Cylinders weren't oversized at all, and pistons had no sign of wear that I could see. Could be one of the valves not seating right? not sure what else would cause low compression.

Thankfully I don't have to worry about any carbie problems!

Cheers
Luca