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Engine basics => Engine set up tips => Topic started by: old fart on February 12, 2006, 11:55:55 AM
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hi randy: what is diferance between foxs head and your hi zoot head. compression ratio , chamber shape,plug location,ect. why is yours better?and why so proformance wise? ??? ???
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Hello OF
My Smith hemi head has ran better in my opinion than any other I have ever ran.
The features of it are:
A- 1 piece as opposed to a 2 piece head, this makes for better heat transfer and stops the possibility of having the button turn and contacting the piston. I have seen this many times.
B- The FOX runs hot when your trying to get power out of it, The SHH has deeper cooling fins and also has extra fins cut around the outside edge of the head, this allows for more power and a faster dispation of the heat.
C- All of the SHH have a heat dam cut around the Glo plug to insult the heat in the plug , we need to run hot plugs to run a 4-2 cycle. The heat dam keeps the plug cleaner in the transitions and helps greatly in making the "burp" less pronounced , or in many cases stopping it.
D- The inside chamber is a hemi design that has just a small increase in compression over the stock one. It runs as smooth as possible while increasing 4 cycle power.
E- The Glo Plug is offset toward the exhaust side to help keep the plug a little hotter and cleaner. element end is canted back toward the center, Sort of like the way the old FOX 36 X was.
There are many hundreds if not now over a 1000 of FOXes running this head
All of the ones I have sold use this head , and 1oos of the Larry Foster Fox 35s were sent with this head also.
I would suggest also asking anyone , who has one, how they like it.
Maybe others who have ran these will chime in here also
Regards
Randy
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RANDY ; THE HEAT DAM YOU SPEAK OF, IS THIS SOMETHING LIKE THE SMALL RING AROUND THE GLOWPLUG ON THE OLD "ranger "head of early fox production,which wasof a low compression ratio ,both i and afriend of mine have run these heads with good results,we are able to get a nice 2x4 brake and no problem with the infamous fox burp,granted,most of ourships are full fuce with upright or inverted engines but ialso have afew profil ships, never had this "burp"every one talks about ??? ??? ???
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Hi OF
I am not sure I have seen a "ranger head" so I can't answer your question.
Randy
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Ron - The heat dam is Randy's way to keep the plug hot. Its a round groove cut from the top of the head down to about half of the thread depth of the plug, prevents the heat from being conducted away from the plug to the fins and dissipated. An intentional hot spot, right at the plug.
Rand - A ranger head is the first 6 bolt head, almost flat across the chamber, with a slight lip, maybe .040 deep, at the exhaust and intake sides of the head. Runs like a hemi. The ranger name comes from the jobshop foundry which cast them. It has a little tiny Ranger logo cast in raised script inside the head. Worth using if you find one, but unfortunately not distinguishable externally from the fox wedge.
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I just got a Smith Hemi Head and don't see what the heat dam is described as. What should I be looking for? Also, what glow plug works well with this head? Any other tips?
Thanks,
Ken
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I use a Thunderbolt hot plug. No problems. I get mine from Randy.
Bill <><
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I just got a Smith Hemi Head and don't see what the heat dam is described as. What should I be looking for? Also, what glow plug works well with this head? Any other tips?
Thanks,
Ken
Hi Ken
You can use the
T Bolt RC long
Fox RC long
Fox Miricle plug
Glo Devil #300
Sig RC long
Enya #3
there are quite a few plugs that work with the FOX 35, you don't need a special plug to work with the head, just the same ones that work with any FOX will work with the Hemi head. most will work better because teh offset design helps keep the plug hotter, resulting in a cleaner run
Regards
Randy