5 replies to this topic

[tomswain17]

hi
my mini seams to lack power i have checked and adjusted the timing but still no different. ive been told that fitting hotter plugs will help with the power. the plugs in at the minute are NGK bp6es. could anyone reconmend a hotter one that will make a difference

[Ethel]

The plugs should be matched to the engines running temperature. If the engine is too cold the plugs won't burn off carbon deposits and will eventually foul. Too hot and the plugs will overheat and cause pre-ignition, pinking, detonation...

The higher the number the higher the operating temperature range of the plug. look at your plugs after a good run to decide if there is an issue.

[Zacherius]

Have you just checked the gap on the sparks and the other ignition bits ?? Or tried something like redex to clean the system out first before thinking of different plugs.

[dklawson]

As Ethel said, the heat range of the plugs is usually matched to the engine. Going on from that, running a "hotter" plug will likely only result in pinging and knocking, not more power.
See:
http://www.users.big...goff/splug1.htm
for an overview of spark plugs. Flip through subsequent pages from that opening page to learn how to read NGK, Champion, and Denso spark plug numbers.

Also as above, go through all the tune up steps before thinking you need different spark plugs.

[tomswain17]

hi thanks for you help everone. my engine dosent quite get up to the 'n' mark so will NGK bp7es plugs be better than the '6es' ones?

[lrostoke]

I'd be very suprised if the problems are down to the plugs.
In our little group we have 3 998's all running either BP6.. or BPR6.. plugs

These are what Haynes recommend

Spark plugs:*
Type:
All models up to 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion RN9YCC or RN9YC
998 cc engine models, 1987 to 1989 . . . . . . . . . . . . . . . . . . . . . . . Champion N12YCC or N12YC
998 cc engine models (1989-on) . . . . . . . . . . . . . . . . . . . . . . . . . . Champion RN12YCC or RN12YC
1275 cc engine models (1990-on) . . . . . . . . . . . . . . . . . . . . . . . . . Champion RN9YCC or RN9YC

N9YC are equivalent to NGK BP6..

N12YC are equivalent to NGK BP5..