Running on just the three cylinders then...

I seem to recall someone having this with 34 icts and it was the float valve, may have been Dandaz?

 

I had this problem on my type 1 but it was No3 not firing. It was down to fuelling. sorted by fitting a balance pipe between the two ICT's . I spent ages adjusting the valve clearances again and again. Even tried compression tests and a leak down test. The balance pipe cured the problem.

 

Thanks earlybaylatebay - there is a balance pipe between the two carbs but I haven't checked it to see if there is a blockage in it; something else for the list of things to check!

 

Thanks to Borninabug and his kind loan of a compression tester, the errant cylinder actually has the highest reading. It's registering 142 whereas the other three range from between 133-138 or just in the green area on the compression tester. They seem reasonably healthy figures or do they mean the valve clearances are way out?
All spark plugs are black and wet, so there's a lot of fuel going in and the balance pipe I've just noticed now I've had a thorough shufty, is kinked/compressed just by the lhs carb. It looks like someone has used some manky, old fuel pipe so I'll renew that in the morning and see if that makes any difference. There is also a T piece with a branch heading forward, presumably to the servo. The engine is a replacement and is a 2.0l GE version so suspect it should have hydraulic tappets.
Thanks for the help and advice so far - much appreciated.

 

the compression readings are nice and healthy

 

My 2.0 was running on three, one of the four wires to the balast resistor on the fire wall was damaged right where it goes into the resistor. Soldered back, all good. Worth a look ?

 

I ran my old '79 tintop on 3 cylinders for months

 

Thanks I'll check the balast resistor as well - seems the check list continues to grow!!

 

You won't have the ballast resistors as you're running carbs and not EFI

 

Thanks Paul,

one less thing to check then! There is something on the hanging on the firewall - I'll post a picture tomorrow. Glad to know the compressions are ok. My only restoration was a car which I'd known for 30 odd years and knew it inside out so this is uncharted territory as it's been through many, many hands, so I expect many surprises, not all pleasant.

 

Here's a picture of something mounted on the firewall with several wires emerging from it. I have no idea what it is or what it does so grateful for any advice. I've replaced the balancer pipe with new tubing and whilst it hasn't cured the misfire it some how doesn't seem quite as noticeable although still popping through the exhaust on the over run when revved.
The second image looks like a relay - hot start?

 

First is the regulator. Second is the relay for the fan.
But Im on tapatalk so it could be a tiny shoebox....

 

Thanks Matt and very keen eyesight if you're viewing it on an iphone.
Didn't realise the regulator wasn't built into the aalternator so learn something new everyday!

 

Yes what Matt said

 

Taken a while but the specialist has finally sorted it!
Step forward those who said tappets as that was the cause - you were right; they're hydraulic and since adjustment it's running much better and on all four cylinders.
Thanks for all the help - it's much appreciated!