really random tickover on Aircooled CT
Posted: 16 Oct 2008, 14:21
Right where do I start!... I am gutted as I have paid for Brighton breeze and me van aint running!
I have a 1776 CT with weber 34 twin carbs (yes yes I know CT's are sh1te before you all jump down my neck - I don't have the money to splash out on a 2.0L lump!)
It's been built with new barrels/pistons, was never run and then stood for a few years then I bought it.
When I came to check/set up the engine I found a really odd idling issue in that cylinders 1 and 3 (the two nearest the front of the van) are not really doing much at tickover.
The effect of this is that I cant get the engine to time up properly as it dies when I get to around 5* BTDC, the book states timing should be 4-6* ATDC
Things I have done to prove what and where the issue is.....
Using new fuel
checked carb jets and even rebuilt the carbs
gone back to standard solex single carb (checked that for jet sizes too)
changed coil over for several others
changed plugs
changed plug leads
Tried with/without idle stabiliser unit
switched over to traditional points dizzy from the electronic one which has no vacuum on it ruling out bad vacuum
swapped out condenser
even went to the stage of rotating the dizzy through 90* and then re-leading it to try and move the problem to cylinders 2 and 4 with no joy
I have an old Gunsons see though spark plug kit thing which allows you to see the colour of the igniting fuel inside the cylinder/s and it looks good in all cylinders so unless it's running really lean (on twin webers?.. not likely!)
Valve clearances have been checked and reset
Compression test shows in the green on the scale (cant remember the actual reading!)
Given what we have done to date I can confidently say the issue ain't electrical or carb as they have both been totally replaced in the fault finding exercise
Were at a loss as to why it ticks over so poorly on these two cylinders yet it will rev up and appears to run on all four cylinders - removing plug leads on 1&3 does nothing to tick over regardless of what we do.
The only last thing I can thing of is that the engine has shorter con-rods on those cylinders?
I am currently standing next to the van with a lit match near an open petrol cap!!
- can anyone enlighten me as to where the issue could be/where to look next and stop me from dropping the match into the tank! 
I have a 1776 CT with weber 34 twin carbs (yes yes I know CT's are sh1te before you all jump down my neck - I don't have the money to splash out on a 2.0L lump!)
It's been built with new barrels/pistons, was never run and then stood for a few years then I bought it.
When I came to check/set up the engine I found a really odd idling issue in that cylinders 1 and 3 (the two nearest the front of the van) are not really doing much at tickover.
The effect of this is that I cant get the engine to time up properly as it dies when I get to around 5* BTDC, the book states timing should be 4-6* ATDC

Things I have done to prove what and where the issue is.....
Using new fuel
checked carb jets and even rebuilt the carbs
gone back to standard solex single carb (checked that for jet sizes too)
changed coil over for several others
changed plugs
changed plug leads
Tried with/without idle stabiliser unit
switched over to traditional points dizzy from the electronic one which has no vacuum on it ruling out bad vacuum
swapped out condenser
even went to the stage of rotating the dizzy through 90* and then re-leading it to try and move the problem to cylinders 2 and 4 with no joy
I have an old Gunsons see though spark plug kit thing which allows you to see the colour of the igniting fuel inside the cylinder/s and it looks good in all cylinders so unless it's running really lean (on twin webers?.. not likely!)
Valve clearances have been checked and reset
Compression test shows in the green on the scale (cant remember the actual reading!)
Given what we have done to date I can confidently say the issue ain't electrical or carb as they have both been totally replaced in the fault finding exercise
Were at a loss as to why it ticks over so poorly on these two cylinders yet it will rev up and appears to run on all four cylinders - removing plug leads on 1&3 does nothing to tick over regardless of what we do.
The only last thing I can thing of is that the engine has shorter con-rods on those cylinders?
I am currently standing next to the van with a lit match near an open petrol cap!!

