Looking for a model t t thread priming cup spark plug for explosion whistle. I don't care about the brand just want one that will spark.
Champion H-14 are the most available but still expensive.Would it be doable to drill and tap a reg plug? Bud.
That's always a possibility, but I would prefer an original plug.
I see them come up of T-bay every once in a while.
Were there any at Bakersfield?
Here's one if you have deep pockets:
Most regular plugs can't simply be drilled as the sealing ring for the electrode is level with the top edge of the threads. In other words, one can't drill into the flat where the wrench goes as the hole would be above the porcelain sealing ring, isolated from the combustion chamber. One of the only plugs I can think of that is built in such a way as to be an exception to this rule is the old green splitdorf plugs as they seal above the wrench flats.
Maybe you are already aware of this. Explosion whistles originally came with an adapter to accept the spark plug. However, more whistles have survived than adapters.
Reproduction adapters are available from MAC's:
I think i have 6,4 in the engine and 2 in the tool box.At 100.00 it should be perfect nos.Bud.
The issue with the adapters is that they raise the spark plug up and away from the cylinder reducing the ability to properly combust the fuel mixture. These new adapters lift the plug over an inch above the cylinder and have a restrictive smaller hole at the bottom of the adapter.
Here is one I have. Compare the photo to the description I gave above.
Here is another one.
Not a "T" plug !
We have had the explosion whistle on the 12 for 50 years and the plug is an inch or so out of the cylinder. Broke the crank after 101 years of service now the engine is apart, you can not tell which cylinder the whistle was in they are all same. There is no damage. I have looked at using a primer plug but that would put the hole so far down in the you can't get a fitting on it.The whistle was put on in 63 or 64.
Like Colin, with the whistle connected to an adapter or without the whistle one can not tell any difference in the performance of the motor, except when the whistle is actually being used.
I put it down to the fact the compression ratio is so low the adaptor hardly changes things.