Which Spark Plug to Use in Early Low Head
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Distagon2
Topic author
Which Spark Plug to Use in Early Low Head
I have a 1912 with original engine. My question is what type of spark plug do you folks with the early Model T "low" heads run? My understanding is that the early heads had a moderately higher compression ratio. In the photo below there is a repro Champion X on the left, and an earlier Champion X original on the right. When I assess the early low head combustion chamber, I conclude that a repro Champion X would run too hot as it protrudes too far into the combustion chamber. What plugs do you run in the earlier, low cylinder heads (assume an all-stock engine setup).
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RajoRacer
- Posts: 5172
- Joined: Sun Jan 06, 2019 12:18 pm
- First Name: Steve
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Re: Which Spark Plug to Use in Early Low Head
I run straight side Champion X plugs but they're not reproduced & useable originals are few & far between !
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NealW
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Re: Which Spark Plug to Use in Early Low Head
I run the repo Champion X plugs in our 1911 touring (and 1911 engine) and it runs fine.
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speedytinc
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Re: Which Spark Plug to Use in Early Low Head
The compression differences in the early heads are minimal. 4-1 vs 3.9-1.
I currently run the new brass tops in a milled head with hi dome pistons. 95# compression. (6-1)
Previous was stock head & compression. Both ways ran fine.
I currently run the new brass tops in a milled head with hi dome pistons. 95# compression. (6-1)
Previous was stock head & compression. Both ways ran fine.