HELP VB missing

[Frank Grimes]

My 6cyl vb has a engine miss that I just cant get rid of.Engine misses when driving steady state with throttle just cracked.Ive clean carbie twice with air/carbie cleaner,changed plugs and tried tuning it out with mixture screw and timing...no difference.
Have noticed plugs are white and mixture screw has no effect after two turns out.Single Stromberg....any suggestions?

 

[rambunctious]

Could be any number of things.
Is it missing under load or stationary or both ?

Screw mixture screw in until it stops GENTLY.
Screw mixture screw out 2.5 turns.
Get a trigger spray bottle and fill with fuel.
Start engine and spray fuel around carbie to check for leaks.
Be careful not to set the thing on fire.
If the engine increases in revs while doing this, then you have an air/vacuum leak which needs to be fixed.

Assuming it has an electronic dissy, is it in good condition ?
Are plug leads in good condition ?
Is dissy cap good ?
Is coil good ?
What fuel pump ? is it good ?
Have you done a compression test, were all cylinders close in compression ?
Are any plugs oiled up ?

 

[Frank Grimes]

As I said ,plugs are super clean and missing is only at very light cruise otherwise all good.Fuel pressure is high @ 8psi but no signs of flooding.

 

[Lacksballs]

Have a good look for a vacuum leaks, carb base, brake booster, modulator line (if auto), vacuum advance unit, all vacuum lines (dash, dizzy, pollution canister, etc) as if you have a leak & you maybe masking it by adjusting the mixtures. Another thing to check is float level.

 

[whats up]

My 6cyl vb has a engine miss that I just cant get rid of.Engine misses when driving steady state with throttle just cracked.Ive clean carbie twice with air/carbie cleaner,changed plugs and tried tuning it out with mixture screw and timing...no difference.
Have noticed plugs are white and mixture screw has no effect after two turns out.Single Stromberg....any suggestions?

When the VK had a miss once it turned out to be a HT lead
Have U tested each one?

 

[ellisjuan]

My 6cyl vb has a engine miss that I just cant get rid of.Engine misses when driving steady state with throttle just cracked.Ive clean carbie twice with air/carbie cleaner,changed plugs and tried tuning it out with mixture screw and timing...no difference.
Have noticed plugs are white and mixture screw has no effect after two turns out.Single Stromberg....any suggestions?

Some things you can check:
- Ignition points & rotor
- Ignition timing
- Distributor advance springs
- Spark plug gaps
- Ignition coil
- Carby gaskets
- Vacuum hoses - look for cracks
- HT leads

From the symptoms, I'd say its more an ignition problem than fuel.

 

[Frank Grimes]

I checked for vac leaks,all seems good.I'm starting to think ignition too cos the miss seems to be at a certain rpm point not throttle position.Btw,whats pcv valve supposed to be doin at idle? rattling or sucked closed.

 

[ellisjuan]

The PCV will rattle at idle... it probably doesn't have anything to do with your problem.

 

[DerekP]

My money is on HT lead(s) / coil.

 

[fxxxrr]

i had a brand new plug cause a miss once, chased it for near on 12 mths totally missed it as i thought na cant be the plugs they re new