Spark plug part number for Winfield head.

[bdave_mcc]

Anyone have a part number for good plugs to use in an aluminum Winfield head?

Thanks in advance!

[hardtimes]

Originally Posted by bdave_mcc

Anyone have a part number for good plugs to use in an aluminum Winfield head?

Thanks in advance!

Hey dave,
Well what CR is the alum head that you intend using ?
The higher the CR, the colder plug is used.

[bdave_mcc]

Originally Posted by hardtimes

Hey dave,
Well what CR is the alum head that you intend using ?
The higher the CR, the colder plug is used.

It's a 7:1

[just plain bill]

I use NGK bp 6 or 7

[colin1928]

What bill said same here

[bdave_mcc]

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Whats the difference in the 6 and 7. Also I see several different ones, it appears to just be difference lengths. Is the shorter one the one to go with?

[colin1928]

BP6ES or BP6HS
6 is hot than 7 road test for which 1 works best
B - 14mm thread dia
P - Insulator
6 - heat range
E - 3/4" thread reach H -1/2" reach measure the threads in your head
S - standard electrode

[Jim Brierley]

Most aluminum Winfields had 14mm thread and need a 1/2" reach plug. Before installing the head put a plug in, you want to utilize all the threads in the head but do not want the plug to extend into the chamber. I use Champion H-8 or H-10's. A 3/4" plug will likely extend into the chamber, build up carbon and ruin the threads when the plug is removed.

[johnneilson]

Originally Posted by Jim Brierley

Most aluminum Winfields had 14mm thread and need a 1/2" reach plug. Before installing the head put a plug in, you want to utilize all the threads in the head but do not want the plug to extend into the chamber. I use Champion H-8 or H-10's. A 3/4" plug will likely extend into the chamber, build up carbon and ruin the threads when the plug is removed.

Or will get hit by valves and make more of a mess.

If you have the luxury of having the head off the motor, you can use the longer plugs with copper "indexing" washers and optimize the installed height.

I had one where I had to weld up the existing holes, re-drill and tap on an angle and use 10mm plugs to clear. Problems solved on a not so normal motor.

J

[Tom Wesenberg]

Be sure to use anti-seize on the plug threads.