Club 80-90 Forums

hi all, I have rebuilt my top end with new valves and guides and fitted new piston rings. I have also fitted a new powerspark dizzy and a new coil. My problem is its only firing on two cylinders. pots 1 & 2 are not firing at all and the heat exchanger is cold. I have fitted new plugs and leads ect but no joy. I have changed my carbs from my twin webers to the solex carbs to eliminate and its still only firing on two. All the leads ore on the correct way from the dizzy to plugs 1432. can someone please tell me the correct way of setting up the tappets as I might have got the timing wrong. I have tdc on number 1 then adjust the tappets then turn the fly wheel anticlockwise half a turn to bdc then adjust number 2 rockers then do the same for number 3 and 4. is this correct. anyone got an idiots guide to setting this up please? sorry this is the first time I have ever done this and its getting to me now as the van has been sitting there for 3 months.

cyls 1&2 are next to each other so it would seem to be something that affects both which would suggest a fuel/carb/inlet manifold prob. I would check compressions first and if ok them try getting someone to turn eng over for a second or two with plugs attatched to leads and observe if plugs fire. That way if compressions are ok you know valves can't be prob and neither can H.T. side of things.
Is it backfiring through cyl 1&2 carb ?
Your valve adjustment method is ok but comp. check would rule out valves if it's ok.

Hello,

bri-on-1 wrote:hi all, I have rebuilt my top end with new valves and guides and fitted new piston rings. I have also fitted a new powerspark dizzy and a new coil. My problem is its only firing on two cylinders. pots 1 & 2 are not firing at all and the heat exchanger is cold. I have fitted new plugs and leads ect but no joy. I have changed my carbs from my twin webers to the solex carbs to eliminate and its still only firing on two. All the leads ore on the correct way from the dizzy to plugs 1432. can someone please tell me the correct way of setting up the tappets as I might have got the timing wrong. I have tdc on number 1 then adjust the tappets then turn the fly wheel anticlockwise half a turn to bdc then adjust number 2 rockers then do the same for number 3 and 4. is this correct. anyone got an idiots guide to setting this up please? sorry this is the first time I have ever done this and its getting to me now as the van has been sitting there for 3 months.

That is the way to do the valve timing...

How much have you 'pre loaded' the tappets (assuming hydraulic)..

A compression test will give us more info.

Does the RH carb 'spit' when you open the throttle..

Have you got the throttle butterfly correctly set..

Are the idle mixture screws set at 2 1/2 turns ( to start with)..

Have you watched the Solex carb tuning video

https://www.youtube.com/watch?v=najLc9GlLJ0" onclick="window.open(this.href);return false;

You'll get there..

Cordialement,

I have found the problem, one of the threads has pulled out of the head on the manifold. I have ordered a new 8mm to 9mm thread and a new 9mm tap set for it. Compression is good all round, 1 1/2 turns in preload on the tappets, no spitting on the rh carb and idle mixture is set to 2 1/2 turns out. So it looks like its drawing in to much air to fire on pots 1&2.

bri-on-1 wrote:I have found the problem, one of the threads has pulled out of the head on the manifold. I have ordered a new 8mm to 9mm thread and a new 9mm tap set for it. Compression is good all round, 1 1/2 turns in preload on the tappets, no spitting on the rh carb and idle mixture is set to 2 1/2 turns out. So it looks like its drawing in to much air to fire on pots 1&2.

Nice to have a problem found posting describing in detail what was found and method of repair,Thanks.