What do you all think Cyl 4 is way worse than 6 . All other plugs look brandie new . Valves are a little loser than I would expect ( 30-30 Cam) ..034 Lash on the exhaust Started out at .024-.027

What do you all think Cyl 4 is way worse than 6 . All other plugs look brandie new . Valves are a little loser than I would expect ( 30-30 Cam) ..034 Lash on the exhaust Started out at .024-.027.


Assuming wires,cap,rotor ,etc are in order , i would start by checking compression

Is your cylinder compression less ( might be since they are foulled) on 4 and 6. If so add some oil to cylinder and re-check compression. If considerably less, you need to check why cylinders are low on compression

If compression is even all around, you might want to check your idle mixture screws and make sure your carb is in proper working condition.

Keep gap at .30,

I personnaly use a infrared thermometer, i point each cylinder exhaust and compare temps from side to side. Front should be colder, middle should be very hot(since they are close together) and rear should be hotter then the front.

Uh Oh!....I'm thinking blown head gasket if plugs look wet!

Generally a blown head gasket gives very clean plugs....like when pull a head with blown gasket the cylinder is clean of deposits....The same principle of the old school de coke by dribbling water down the carb.

Try changing or swaping the leads and plugs with a good cylinder...
Fire up the engine at night and watch for any arching....or if brave run your hand around the dizzy cap and down HT leads...have someone stand by to tell up which lead makes your hair stand on end .... not recommended.

Spark plug wire 4 and 6 corroded at the dizzi cap

Spark plug wire 4 and 6 corroded at the dizzi cap

Dont lift the hood when it rains lol....
I have got caught out on that every 6 or 7 yrs....forget that happens even with good boots...and discover when swaping plugs and leads to check.