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Fw: 2.5 liter motors

Forwarded from the Merkur List.

Rick is THE Rick Byrnes, land speed record holder in a Merkur, and a Ford

This is the best info I've seen on this subject.


> Subject: Re: [M] Scorch correction, and 2.5 liter motors
> Date: Thursday, August 28, 1997 10:37 PM
> In a message dated 97-08-27 10:05:19 EDT, you write:
> >  I noticed that the base 2.3 liter engine in the new
> >  redesigned '98 Ford Ranger has received an increase in stroke bringing
> >  displacement up to 2.5 liters. The obvious question in my mind, is
> >  or not this crank is compatible with our 2.3 turbo blocks. Are the
> >  journals the same size, the oil seals the same style, etc. ? If so,
> >  could turn out to be an inexpensive way to gain displacement in our
> >  without going the forged aftermarket route. Does anyone know anything
> >  about this truck engine?
> Good Morning
> A short response before getting out to the shop.
> The 2.5 is indeed a 1/8" stroker in a standard deck height revised block.
> The crank main bearing journals are smaller than ours.  This change was
> actually made in 1989 "dual plug" ranger engine.
> The crank is fully counterweighted, and as a 2.5 without ballance shafts
> is much smoother, and the center main brg will be a lot less stressed.
> But if you want this deal you need the whole short block.
> The new block is much changed.  It has a canister oil pump that is
> where the aux shaft used to be.
> There is good news and bad news.  The changes to the block make it
> to produce new castings of the old configuration.  There are NO new
> blocks of the older 2.3 variety available, nor will there be ever.
> If you are into this engine for the long run like me, find parts now. 
> same goes for the heads. (different story and different deal, and I can't
> talk about that now).
> The new block has been thoroughly engineered with lots of analytical
>  The bores are siamesed at the very top for rigidity, the head bolt
bosses go
> all the way down to the main bearing bosses.  (Less bore distortion, and
> more strength.  The bad ? part is there are now windows in the main
> bulkheads.  I suspect torsional rigidity is compromised when power
> are doubled and trippled like we have done to the stock turbo blocks.  I
> not seen the block but my source says it is really nice, and properly
> designed for a 150 HP engine.  These days we do not overdesign components
> like we did in 1970 when our parts were going thru the original design
>  Today, the guys that designed the original 2.3 would get a bad
> review because it is too strong, too heavy, too hard to manufacture, too
> heavy, too strong,,,,,,,,,,you get the idea.
> At any rate, the engineers did a good job of redesign and as a non
> production base engine for a little truck , it will perform very nicely,
> less NVH than ever before.
> On the subject of ballance shafts, the return on investment (when you
> consider  a weight penalty, cost penalty, and royalties that must be
> (Mitsubishi has the current technology pattened ) may not make sense.
> In 1983 the ford engineering community was working on ballance shafts for
> this engine, but was eventually cancelled because of  limited improvement
> a base engine.  (perceived by the customer sitting in the drivers seat.
> We all did not agree, but then we are the simple engineers, not the
> that make all the decisions.  I believe of course that Ford would like
you to
> buy the optional engine.  They make more $.
> In fact they want you to upgrade to the bigger trucks,,,,,,they make even
> more.  Corporate America,,,,,,,,, Fortune 2000,,,,,,,,,it's all about
> profit............
> Rick
> 211 in 97