# Panther Pup Heads



## jpaul (Jan 27, 2009)

I finally came up with a cylinder head arrangement for my Panther Pup. But I am concerned on several issues. First, this engine as originally designed tends to over heat so I may not have enough fin area.







Second, I planed to use long reach spark plugs but even the longer plugs are .050" short of the inner surface of the head.











Any suggestions?


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## Kermit (Jan 27, 2009)

Aren't you losing a bunch of radiating surface area by having the cylinders touching?

Could you get more cooling if each cylinder had 1/4 or 1/3 of a cylinder size air gap between?

If you can't separate them that much how about using a water jacket that goes between the cylinders?


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## GailInNM (Jan 27, 2009)

Paul,
Take a look at your plugs. I just looked at one of my Stitt plugs, and it looks like the section above the thread could be extended an additional up to about 0.080 by turning that part down to the minor diameter of the thread. I don't think that would compromise the plug any. Might be different on your plugs however. 

Also, most of the supplied plug washers are much thicker than necessary. You might be able to gain another 0.010 reach with a thinner washer.

Gail in NM,USA


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## chuck foster (Jan 27, 2009)

excellent looking work :bow: :bow:

why not try making your own plugs?
i have made lots of plugs, there not hard to make and they work very well.


chuck


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## gbritnell (Jan 27, 2009)

If you can't find plugs the length you need why not make your own. I made the ones in my 4 cylinder OHV engine because I couldn't find what I needed. It's really quite an easy job. The insulators are made from virgin teflon. It machines well and holds up quite well in the combustion chamber.
gbritnell


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## ksouers (Jan 27, 2009)

Paul,
Yes, very nice work.

As for overheating, how about an auxiliary drive to power a fan?



Kevin


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## jpaul (Jan 29, 2009)

Kermit, I can't get a gap between the cylinders as large as 1/4 cylinder width, but I can increase the existing gap. Currently the gap is about .050". I am sure I can increase this to .10" without encroaching into region adjacent to the head bolts. I agree that there is a lot to be gained by getting more air space between cylinders.

Gail, gbritnell and Chuck, Thanks for your excellent suggestions on solving my spark plug problem. I like the "make your own" and I am sure you know why! But most likely I will take a path similar to what Gail offered.

I can not deepen the spark plug 1/2 counter bore. It would break into the ports by roughly .020" on each side. But I can deepen the counter bore with a 3/8" EM another .050-.070"

Thank you all. It is such a relief to have help, a key stroke away.


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## PhillyVa (Jan 29, 2009)

Now there's a line that should be added to the HMEM logo...



> It is such a relief to have help, a key stroke away.



I like that!

Regards

Philly


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