Essex spark plug types

[oldgeebee]

I've just noticed that my engine is fitted with NGK BP7HS plugs. I believe the recommended plug is NGK BP7ES (or the slightly hotter 6ES). The difference is that the H has 12.7mm reach whereas the E has a 19mm reach. I've fitted one 19mm reach plug and turned the engine over a few time with a spanner on the crank and there doesn't appear to be any interference. Is there any logic in fitting a shorter reach plug?

TIA

GB

[plasticpig72]

In my 3000M the plugs are NGK BP6ES they seem o.k.
Alan

[347Andy]

IIRC BP6ES is the standard fit in the Essex

[oldgeebee]

Agreed - all the references I have found say that the BP6ES is the correct plug. I'm just curious as to why someone would fit the shorter reach BP6HS/BP7HS in my engine.

GB

[plasticpig72]

If they can fit the wrongs plugs you need to check other things carefully on your car
Alan

[bluezeeland]

Graham, the 6E ratings are indeed correct for both heat and reach......don't go IX, essex' don't like em, for some reason...

[oldgeebee]

Hi Frank, I've got a set of the long reach plugs ready to go in but I'm just being ultra cautious about using them. I can't see why anyone would have used short reach without a reason . . . would hate to dent my pistons!

GB

[bluezeeland]

oldgeebee said:

Hi Frank, I've got a set of the long reach plugs ready to go in but I'm just being ultra cautious about using them. I can't see why anyone would have used short reach without a reason . . . would hate to dent my pistons!

GB

Hi Graham, believe the reach of the E' are 19 mm, which did not pose any problems in the engine of my car, on standard pistons, unless they are changed on yours ?

[oakdale]

If they've been in for a while, you may find that the lower part of the thread in the head is coked up with carbon.

If this is the case, you'll need to get a plug thread chaser to clean them up.

[bluezeeland]

oakdale said:

If they've been in for a while, you may find that the lower part of the thread in the head is coked up with carbon.

If this is the case, you'll need to get a plug thread chaser to clean them up.

Now, thats is good thinking, and very true !