Can you make up the compression loss by skimming the head and using dished
pistons?
-----Original Message-----
From: alpines-bounces@autox.team.net [mailto:alpines-bounces@autox.team.net]
On Behalf Of tom.hill@att.net
Sent: Wednesday, February 03, 2010 5:03 PM
To: Tony Somebody; Alpine List; Beamclub
Subject: Re: [Alpines] Holbay engine help
Tony,
I have a Holbay head on my original SV Alpine block. It fits perfectly with
no modifications required to either the block or head. As you observed, the
combustion chamber has been reshaped on the Holbay head and you must use flat
top pistions to restore the compression ratio.
One thing to be aware of is the intake runners in the Holbay head are smaller
than the standard Alpine head and the Hunter engine was tilted over 15 degrees
or so. This means the Holbay intake cannot be used on the Alpine without
being cut and rewelded to account for the 15 degress. And, if you use a
manifold that was intended for use on the standard Alpine head, there will be
a "step" between the intake and head. Not the best scenario for performance.
I have the setup on my car and it made 120HP at the crankshaft on the dyno. I
had the Holbay side draft intake modified but it was still too close to the
steering box. I am using the Redline manifold and it fits fine. I had the
inside of the intake runners welded up and smoothed to match the Holbay head.
I haven't finished the installation so I can't comment on the "roadability" of
the setup
Good Luck,
Tom Hill
-------------- Original message from "jarrid_gross@earthlink.net"
<jarrid_gross@earthlink.net>: --------------
> Tony,
>
> The holbay setup in an alpine can use any 1725 block. The Hunter 1725 block
has side motor mounts, so you cant use early alpine 1725
> blocks
> in a hunter, but you can use hunter 1725 (or alpine blocks) in an alpine.
>
>
> HTH
>
> Jarrid Gross
>
>
> -----Original Message-----
> >From: Tony Somebody
> >Sent: Feb 3, 2010 1:12 PM
> >To: Alpine List , Beamclub
> >Subject: [Alpines] Holbay engine help
> >
> >As some members know I have both Tigers and Alpines I have been attempting
to
> >build a better than stock 1725 for my S5 w/ OD My first setback was the
> >machine shop some how lost a beautiful head I had spent lots of time
porting
> >then paid a pro to finish up- soon I decided I would like to have a Holbay
> >engine and had made friends with a chap in the UK who had bought a Holbay
> >head, intake and headers several years back and was willing to sell them to
me
> >for what he paid- what a great person this gentleman is but upon searching
his
> >workshop the parts where missing It seems his neighborhood has changed
over
> >the years and what used to be left unlocked is now in need of alarms as
crime
> >is up in the UK too- long story short he had been burglarized but wasnt
aware
> >his Beam parts had also been removed. He is an older gent and says he has
so
> >many bits he may never know what all was taken. Next I met a guy selling
> >Holbay items on epay and although I wasnt able to
> > get the head, he has another Holbay engine. I have help in getting the
> >smaller parts to the USA but I dont think the block is one that can be
> >brought. I need to know if the Holbay uses the same 1725 as the stock
block. I
> >know it uses a different head and of course the cam isnt the same or even
the
> >intake and it uses flat head pistons to raise compression. There is prolly
an
> >American flat head piston that would work BUT thats a guess and wishful
> >thinking ANY information on the similarities or the differences between
the
> >Holbay and the stock 1725 know to our members would be appreciated.Feel
free
> >to contact me off list
> >Thanks in advance
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