Spark Plug adapters

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ModelTWoods
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* REQUIRED* Type and Year of Model Ts owned: 1927 Model T coupe, 1926 4 door sedan
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Spark Plug adapters

Post by ModelTWoods » Mon Mar 16, 2020 11:46 pm

The spark plug adapters from 1/2" pipe thread to 14mm are available, but what it you have a head tapped for 14mm and want to use standard T 1/2" pipe thread plugs? I guess you're screwed. I'd like to add an explosion whistle, but I don't know of any adapters for 14mm plugs.


SurfCityGene
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Re: Spark Plug adapters

Post by SurfCityGene » Tue Mar 17, 2020 2:37 am

You could just drill and tap to the pipe threads. A 1/2 - 14 tap would require a 23/32 drill.
1912 Torpedo Roadster


tmodeldriver
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Re: Spark Plug adapters

Post by tmodeldriver » Tue Mar 17, 2020 9:20 am

Or get a different head.


Topic author
ModelTWoods
Posts: 1049
Joined: Tue Jan 08, 2019 10:53 am
First Name: Terry
Last Name: Woods
* REQUIRED* Type and Year of Model Ts owned: 1927 Model T coupe, 1926 4 door sedan
Location: Cibolo (San Antonio), TX
MTFCI Number: 20180

Re: Spark Plug adapters

Post by ModelTWoods » Tue Mar 17, 2020 10:57 am

If I knew there was enough metal around the 14 mm plug holes without causing problems, I'd drill and tap.

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Mark Gregush
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Re: Spark Plug adapters

Post by Mark Gregush » Tue Mar 17, 2020 12:18 pm

A friend has a Z head with the 14mm plugs. He would like me to drill and tap for 1/2 plugs, but how much metal (aluminum) has been my concern as well. Chances are there is, but really don't want to mess it up.
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
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Kevin Pharis
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Re: Spark Plug adapters

Post by Kevin Pharis » Tue Mar 17, 2020 12:25 pm

I would expect that if the head was originally sold with either spark plug option, there would be more than enough material to support the larger plug variety. I highly doubt there would be a separate pattern just to accommodate the relatively minor dimensional change between the 14mm and the 1/2” NPT plugs

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