Lodge HLN

[paul.wirdnam]

Can someone tell me if the long reach (3/4 inch) 14mm Lodge HLN has the same heat range as the 18mm Lodge H1? If not, what is the equivalent long reach 14mm Lodge plug?

And while I'm at it, I also found a few other new-old-stock 14mm Lodge plugs in my garage, so can anyone tell me anything about them:

2HLN and 3HLN --- higher the number, the hotter the plug??
H14
HN

Thanks!

[pete.collings]

My NGK catalogue shows a HLN equivalent of B6ES, with 2HLN = B7ES and 3HLN = B8ES, thus higher the number the cooler/harder the plug. I believe the HLN would have been the standard plug for an alloy head NH/VH/VB/KH/SQ4, although a 2HLN could be used for harder use. A 2HLN was the recommended plug for an arrow/leader. This info is on the back of a Pitmans Book of the Ariel. It gives a 18mm H1 for use on single cylinder models, but no indication of heat range comparison.

[paul.wirdnam]

I believe the HLN would have been the standard plug for an alloy head NH/VH/VB/KH/SQ4, although a 2HLN could be used for harder use.

Thanks Pete...so which one of these HLN types would be best in an iron head?

[pete.collings]

I think all iron head motors use a short reach (1/2") plug, so the HLN series would be inappropriate, as I believe they are all long reach (3/4").
The NGK equivalent of a HN is B6HS, the Pitman Lodge advert recommends a Lodge CN for an iron VH and early iron SQ4, but a HN (or H14) for a iron NH and a Huntmaster. The NGK reference book (1980) does not give any listing for a Lodge H14.
I use to use a NGK B6HS in my Huntmaster, and have used a cooler B8HS without any real problem when I picked up a batch cheap at an autojumble.

[paul.wirdnam]

I think all iron head motors use a short reach (1/2") plug, so the HLN series would be inappropriate, as I believe they are all long reach (3/4").

I should have explained more...sorry .

I want to use a long reach 14mm plug because I'm using a 18mm-to-14mm adaptor in my OHV Black Ariel --- and a long reach 14mm plug + adaptor results in the same electrode position as a normal reach 18mm plug.

Correct 18mm plug is H1...so I'm trying to work out what the equivalent HLN would be....

[nevhunter]

If you are using an adapter to get down to a smaller size use a slightly colder plug than the equivalent, as the adapter does not provide as good a heat path, as a head without one. Nev

[pete.collings]

I would use as cool a plug as will allow the motor to run satisfactorily, so a 3HLN or 2HLN.
For your info, there is additional info on plugs, including an extensive plug comparison chart in Excel format, under the generic section of the document repository.

[pete.collings]

Some further info, having visited our branch chairman today and mentioned the above topic.
He showed me a 18/14mm plug adaptor, but mentioned that there might be problems with clearance of the hexagon points of the adaptor when fitting to the cylinder head, and also suggested using a cooler plug as the adaptor would reduce the rate of heat transfer from the plug to the cylinder head. I had a look at a H14 plug, which had a triple earth electrode, although the HLN and 2HLN had a more normal single electrode.
Apparently, some Ford motors use 18mm plugs, but they have a tapered seat. A bit of careful work in the lathe will square the seat, and a normal 18mm sealing washer can be fitted.

[Wali.Badger.Taylor]

Why not just run the correct !8mm plug?

[nevhunter]

I do that sometimes. In Australia they can cost a fairbit. I use Champoin D-14 and D 16, the 16 being colder. Some other sizes are very bulky and in the case of some SV engines, sometimes run out of clearance under the tank.
Adapters do run the plugs hotter and sometimes come out with the plug. You have 2 sealing points instead of 1. The only advantage is easier sourcing of plugs for replacement and getting right choice of heat range. Often you need to run a longer length of thread plug in the adapter too, to keep the plug where it was originally in the combustion chamber'
The F head Harleys run an extended length 21mm plug. I have never been able to get "new" ones unless they are old stock and they are rare items indeed.
It is possible to manufacture the plug and use the insulator out of a modern plug. (Just machine the body at the top and the insulator comes out undamaged). Many of the earlier plugs could be dismantled and the insulator cleaned. You just make a copy of the earlier design. Fiddly but not rocket science. Nev