H30 Head: Old VS. New ??

#1
Always heard the old H30 head flowed better, had better compression?
But finally putting these two guys side by side, seems the old has more CC area that would lower compression?
The fins are taller, I believe that would help with cooling but, but.....
Just a question on my bucket list! Thanks! DSCN7542[1].JPG DSCN7543[1].JPG
 

markus

Well-Known Member
#3
your backwards on that, The curved fin is what Tecumseh actually called a "low compression" head....its part number 33209. They were used on 25/30/35 in both horizontal and vertical engines, they were made at the same times as the standard head you have pictured with it which is part number 30579/30579a (yours is a post 1976 version though to clear the plug wire). Not something you would find on an engine Tecumseh made for a mini bike.

The only time you see a curved fin one in a mini bike application is the Aspera made ones on the HT's as far as I know (what Broncco was using). They were made in Italy though, those head have what looks to be the same combustion chamber as the standard 30579 heads did.
 
#4
Thanks Markus for dispelling another myth. Just what I heard over the years, but obviously had very little faith in the claim, seeing so much more in the combustion area. Get to scratch another, "I can't find the answer" off my bucket with holes in it list!
 
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