My last 215 Post.
Ok, Over square engine (ie Big bore, short stroke) is the only safe way
to reach high RPM's. The higher the Piston speed at mid stroke, the
more torque you'll develop because it can twist a lot harder due to the
added length of moment arm. It like using a big ol'e breaker bar to
turn a nut. It WILL turn , but not fast....anyway......The long stroke
engines (Typically big blocks) must speed up and slow down the piston
and rod far more aggressively then a short stroke motor. It is this
huge change in speed and direction that causes the pistons to fracture,
rods to snap in the middle or fold over at the big end. So as long as
the mechanical limits are maintained for the components, a long stroke
engine will produce much more torque, and usually more HP at a given
RPM, simply because, it is easier for the piston to turn the crank.
When dealing with Hot Rod or racing engines, a decision must be made.
What do you want. ? RPM, or Torque. The two never go to gether. I
come from the world of motorcycle racing where the engines I built would
turn in exsess of 16,000 RPM if asked to, and would not break. The drag
bike engines would turn about 12,000, because we needed the torque, so
we increased the stroke.
For just driving around on the street in any kind of normal fasion, and
long stroke engine is better. But I like RPM. I like engines that
whine when they go by. And if I'm racing someone and they have to shift
at 5,500 (stock red line for most engines), I just want to be able to
accelerate right past them and shift at 8,000 if I want. It is purely a
choice. A 289 will beat a 215 off the line every time due to the
torque. I just like short stroke engines.
For the guy that had the broken parts on the machine shop walls. I
would bet they were mostly if not all long stroke engines, that someone
over reved. BOOM out of the block they go !! $$$$$
There is a four bolt main kit from england that is used with one of
their stroker kits for the 215. I want the kit, but not the stroker...
OK. No more on the Buick 215's Well at least until I do one!
Rich
.......We now return you to your normally scheduled
programs......."...And how old is your Sunbeam sir?..."
>----------
>From: marrone@wco.com[SMTP:marrone@wco.com]
>Sent: Wednesday, June 26, 1996 8:48 PM
>To: LeBrun@hii.hitachi.com; tigers@autox.team.net
>Subject: Re: Re[4]: New Thread (was REALLY, REALLY SMALL...)
>
>> Frank;
>>
>> -Even with the steel forged rods & crank I personally wouldn't turn a
>> 289 past 7K. Don't remember the exact specs of the "K" motors right
>> now.Personally, I feel consistent excursions past that RPM without
>> 4-bolt mains on the center caps is risky.
>
>Risky, we are talking hot rodding here right? I assure you that lots
>of hot
>rodded 289s turn post 7000 RPM without failure. BTW, the 215 is a
>2-bolt
>main motor.
>
>> Any engine that's "over-square" (like
>> the 289 with it's stock 4.00" bore & 2.87" stroke) has some inherent
>> defects from a strictly-Physics standpoint to overcome.Can't remember
>> it in detail now,but I fuzzily recall it had to do with stroke, piston
>> & rod weight, crank strength, acceleration and de-acceleration of the
>> whole assembly etc., vs. any given HP & torque output you get at a
>> specific RPM.
>>
>
>What about the Boss 302 (4 inch bore, 3 inch stroke)? Those fortunate
>few
>who own these motors would tell you that they do quite well in the 6000
>to
>8500 range. The main reason why Boss can do this because it breaths so
>well. You can bolt on aftermarket heads on your 289 that breath about
>as
>well. True, the Boss has 4-bolt mains and nicer rods than the regular
>302
>but you can approach the bottom end strength of the Boss with a regular
>old
>302 and modified "off the shelf" rods. Is it risky, well... yes, sure
>it is
>but we're talking about a Hot Rod motor right? If it isn't built right
>or
>you push it a bit too much or you don't pay attention to the warning
>signs
>she's gonna blow but it isn't any more risky than 9000 with a 215.
>
>Frank Marrone MK I Tiger B9471116
>marrone@wco.com 1966 LTD
> Series I Alpine (2.3L powered by Ford)
> Yamaha Seca 900
>
>
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