[tcb] Re: Engine building next chapter

MOMMA , Will said NASCAR.....
--- Will Wood <evilscientistboo@xxxxxxxxxxxxx> wrote:

> Approx 5.4" is the stock length.  Engine Builders
> like to use the term rod ratio.  The higher the rod
> angle, the more stress
> that is put on the rod via side load hence all of
> the I Beam and H Beam rods on the market. The
> advantage however is that you get more low end and
> midrange out of the engine because you're
> accelerating the crankshaft and pistons faster.  If
> you have a higher RPM engine or clearance issues
> then you're forced to longer rods.  In my 2387 using
> Mahle B pistons I have 5.5" rods on an Okrasa 86mm
> crank.  The rod to skirt distance is about .80" at
> maximum angle.  Another drawback to higher rod angle
> is more piston slap but you'll get that with B or
> stroker pistons anyway.
> 
> Another way to put it is a term called rod ratio. 
> That's the length of the rod divided by the stroke
> of the crank.  
> Most engine builders like the ratio to be between
> 1.5 and 2.0.  Again, preferences, experiences may
> vary on that number
> but for a given rod length the lower the ratio the
> higher the rod angle.  NASCAR engines are somewhere
> over 2+ because they
> live at high RPM all day long.  I had to put that in
> there for all the NASCAR fans out here.
> 
> A stock set of rods and a stock crank has a ratio of
> 1.98 (5.394 / (69mm / 25.4mm/in)).  5.394 is the
> actual
> VW Stock Rod length but what's .006 between friends
> right?
> 
> So, assuming Denis goes with his stock 78mm crank
> and stock rods that gives us a ratio of (5.394 /
> (78mm / 25.4mm/in)) = 1.75
> 
> Like I said, stock rods will work on a stroker but
> if you want to play with it invest in some better
> rods.
> 
> 
> 
> -----Original Message-----
> >From: Dan <ThatVWGuy@xxxxxxxxxxx>
> >Sent: Sep 13, 2007 6:55 AM
> >To: tcb@xxxxxxxxxxxxx
> >Subject: [tcb] Re: Engine building next chapter
> >
> >Longer than stock.
> >
> >Someone will correct me but I think stock is 4.8". 
> I'm using 5.0" rods on 
> >my 2017...something like that anyway.  The point is
> if you increase the 
> >stroke of the crank the rod angle changes.  Picture
> a cutaway view of an 
> >engine with the rod on a stock crank with the crank
> at it's highest in it's 
> >revolution.  The rod will be pointing down toward
> the cylinder at an angle. 
> >Now picture it with a stroker crank, the angle
> increases because the 
> >connecting point on the crank just got higher but
> the connecting point on 
> >the piston stayed the same.  By using longer rods
> the connecting point on 
> >the piston moves out reducing the rod angle.
> >
> >
> >
> >----- Original Message ----- 
> >From: "Denis Dodson" <coocoo@xxxxxxx>
> >To: <tcb@xxxxxxxxxxxxx>
> >Sent: Wednesday, September 12, 2007 10:21 PM
> >Subject: [tcb] Re: Engine building next chapter
> >
> >
> >> This is a multi-part message in MIME format.
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> >>
> >> Longer stock rods?
> >>  ----- Original Message -----=20
> >>  From: Dan=20
> >>  To: tcb@xxxxxxxxxxxxx=20
> >>  Sent: Wednesday, September 12, 2007 8:40 PM
> >>  Subject: [tcb] Re: Engine building next chapter
> >>
> >>
> >>  2017cc if 78.4 crank and 2007cc with 78.0 crank.
>  Lots more torque =
> >> than what you had before.  Because of the rod
> angle you should consider =
> >> using longer than stock rods.
> >>
> >>  -Dan =20
> >>  (...who is also building a 2017cc)
> >>
> >>    ----- Original Message -----=20
> >>    From: Denis Dodson=20
> >>    To: tcb@xxxxxxxxxxxxx=20
> >>    Sent: Wednesday, September 12, 2007 10:36 AM
> >>    Subject: [tcb] Engine building next chapter
> >>
> >>
> >>    That is a good idea, Shirley, about the engine
> in Ruby, the Ghia. It =
> >> is almost brand new. And if you will send me the
> Porsche engine, Dunc, =
> >> I'll pop that booger in as soon as I get it.
> >>
> >>    I do think that it will go this way: Tomorrow,
> probably, I will pull =
> >> the engine and take it up to Wayout where he says
> that he has all the =
> >> tools to do machining and build. We will, at
> least, tear it down and as =
> >> Will suggested, see what we have.
> >>
> >>    Then I will either build the new engine there,
> probably using the =
> >> 90.5 pistons and cylinders, or take the parts and
> bus down to Chuck's =
> >> and build it there the week before T@P.
> >>
> >>    I have to tell you guys that it fees really
> cool to have four =
> >> engines offerred as loaners, not even counting
> the Ghia. Thanks y'all.
> >>
> >>    So, if I use the 90.5s and I have a 78.4
> stroke, what will the new =
> >> engine size be, and what is the formula, anyway?
> Multiply, add? I have a =
> >> 1914, how do you get that number
> >>
> >>
> >>
>
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> >>
> >>    No virus found in this incoming message.
> >>    Checked by AVG Free Edition.=20
> >>    Version: 7.5.485 / Virus Database:
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> >> 9/11/2007 5:46 PM
> >>
> >>
> >>
> >>
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> >> 9/12/2007 10:56 AM
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> >> <DIV><FONT face=3DArial size=3D2>Longer stock
> rods?</FONT></DIV>
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Paul Smith
www.23window.com/thezone

T.C.B.
H.B.B.

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