<VV> 1965-1967 110HP with a/c low compression engine

[James Davis]

I think Tony is right here.  There is no tumble or swirl in the small 
valve, bowl shape chambers due to the design of the intake ports and 
the shape combustion chamber.  At least with the 94/110 heads, the 
squish area in the head was an attempt to induce tumble into the 
mixture.  I think one reason the big bore engines are so octane 
tolerant is the un-shrouding of the valves on the 140 heads induces 
some swirl to the intake mixture and the greater squish area induces 
more tumble promoting a faster burn.
Jim Davis


At 11:46 AM 10/24/2006, Tony Underwood wrote:
>At 07:38 PM 10/23/2006, LastHamlet wrote:
>
>
>>What is really different about the Type B Engines????
>>What did GM do different to make these engines
>>originally run (In 1967, with 1967 gas), at 24 degrees
>>BTDC. The specs call for the 1110319 dizzy in both,
>>the same vacuum advance, the same engine
>>displacement(110HP being at question),,,,,,,,,, So,
>>what gives, and has anybody else ever wondered
>>that???????
>
>
>All that comes to mind for me is that perhaps these engines might 
>have, for whatever reason, been fitted with those nasty-ass 
>open-chamber heads ala the '65-66 turbo engines or the later smog 
>engines.   Not having seen a B type engine apart, I'm not sure.   I 
>have stashed away a B type engine with the 24 degree timing plate on 
>it, but I got it sans heads.  It's apart in boxes.   Not sure what 
>the crankcase number stamp is...  crankcase is mixed up with some others.
>
>Those open-chamber heads required all sorts of ignition advance in 
>order to light the charge completely due to the lousy flame front 
>propagation resulting from a bowl shaped chamber "lit from corner".
>
>
>>Cause what keeps sticking out in my mind, is what Bob
>>wrote, and many others I have spoken to keep saying,
>>timing set that high initially, is compensating for a
>>bad design or something.
>
>
>IMHO, those "bowl" shaped open chamber heads were certainly a bad 
>design, makes me wonder why they ever existed in the first 
>place.     The std squish-area 95 heads offer up the same range of 
>compression and work so much better, and do NOT require anywhere 
>near 24 degrees of advance under any circumstances.
>
>
>
>tony..
>
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