Question: Maximum heat resistant spark plugs & spluttering

[julian67]

Hi

1) Would anyone know the maximum spark plug heat resistance for a '71 1.3S Fulvia coupe?

2) Could I put NGK BCPR8E or, 9 spark plugs without damaging the engine?

My mechanic fitted NGK BCPR6E but engine splutters from 3-4 (plenty of power), Plugs are fouling (black even after a very short run) Compression is 130 psi on all 4 cylinders.

Contact points are new and the gap is set correctly. New condenser. I also changed the Marelli distributor cap and last week, replaced a worn inlet manifold gasket, so no air. New fuel pump

Yesterday, I removed the fouled plugs and fitted NGK BP6ES . I had spark at the contact points but no spark at the new leads.

I replaced the old NGK BCPR6E plugs and the engine fired up but still splutters.

3) Would replacing all 4 NGK BCPR6E plugs or, 8/9 resistance, cure this splutttering?

Based upon the above, could anyone advise as to:

The maximum plug resistance?
Spluttering (bouncing from 3-4 on a warm engine)

Would incorrect mixture cause spluttering?

Many thanks

[julian67]

Problem solved!

Faulty plugs!