[YouTube]k-nyzgAL3dQ[/YouTube]
Engine:
1275
Stage 3 Head
1 3/4 carb
Race Needle
K&N
Straight Through Exhaust
Magnecor HT Leads
Split fire plugs
Megaspark Optromic Coil
Issue:
While reving/driving the car there is lots of vibration that feels/sounds like it is misfiring/juddering, this is below 2500/3000rpm.
Checked:
There is a healthy spark on all cylinders
The mixture is at a good point
Engine mounts are secure
Earth strap attached
Timing is set
Fuel pressure is set at 3bar
Fuel filter and air filter are clean
All vacuums as should be - no leaks
Firing order 1-3-4-2 (anti)
Things that dont seem right
The spark plugs are either always solid black or wet (however can not lean out - just backfires)
The only needle it likes running with is BDD (turbo)?
I am weary of how the timing is set at the chain as it looks at TDC that the dizzy is pointing at cylinder 2 rather then 1 (anti)?
Things i have tried
Different dizzy
Standard leads
Unipart and NGK plugs
Different carb
Selection of needles
Difernet airfilter
Headgasket
129g40 head
Standard and sports coil
All mixture range on all needles
Next thing to try
Going to be putting a weber on to eliminate any carb/mixture fueling issues/questions.
Pondering thoughts
Camshaft - lumpy cam?
Crack in the block internally?
Timing 180 out on the chain? - really hoping that the engine coming out is the last thing!
If anyone has had this issue and tried these things or has an idea of something i may of missed or haven’t tried then i would be extremely grateful of your input.
