Louis,
I found the pistons in the UK at RJ Grimes, they are actually the low
compression version. Measured the wall thickness through the large water passage
on top the block, the one that feeds the steam vent in the head. The only place
the measuring device would fit. This block had no liners and the few places wall
thickness could be measured it was in the .240-.285 range. That is before
boring, and it was .020 over to start. So after wall thickness is .155-.200 is
that enough ? Guess I will find out.
The compression height on the Avenger pistons is less than the Alpine by .115,
the chevy rods are .075 longer the new stroke is 3.35 using the small journal
[2"] chevy rods. My crank is not back from being ground but others have done
this so I assume it can be done. The longer rod and half the extra stroke comes
to .125 so the piston is .010 higher than stock. From actual measuring, paper
calculations and Kentucky windage figured the compression would be 11 to1. That
is with my head as it was, I had reworked the combustion chamber as Vizard
suggests in his book. So after much head scratching ended up removing more
material from the combustion chamber and now figure to be at 9.7 to1. Is it
livable with the wall thickness, time will tell. I do know the New Zealand
fellows are running this bore and larger without liners. The head gasket has me
scratching my head if I decide to have one custom made I may have it done
thicker than stock to gain some ccs and drop the compression a bit more. Jim
Louis & Laila wrote:
> Jim,
> Where did you buy your pistons? And how did you determine that the
> block could safely be bored that large? The articles I read said that the
> mech left the piston to head height very high to keep the compression 9.2:1,
> so as not to blow a hole through the cylinder walls.(this is the guy who did
> not sleeve the block).
> Also, how did you change the stroke? There isn't really that much on the
> crank to grind if you go to the chevy rods. Just curious. I read all my info
> from the SAOC "HORN". Lou
> ----- Original Message -----
> From: <ellis838@concentric.net>
> To: <alpines@autox.team.net>
> Sent: Wednesday, January 24, 2001 6:32 PM
> Subject: Re: Tigers in Print
>
> > I am going that route, only using chevy rods. I skipped the liners and
> just bored
> > the block to take the 86.1 mm Avenger Tiger pistons. With the new stroke
> and big
> > pistons the engine will be 1980 cc. I am getting close to being finished
> just a
> > few more bits to round up, early flywheel, timing chain/gears, 7/16 head
> bolts
> > and webers.... Jim 66 SV
> > sosnaenergyconsulting@home.com wrote:
> >
> > > Wow, 1.9 liters and 200 horsepower! That engine must have had some
> > > grunt. I'm a little surprised that more folks don't go that route to get
> > > a power increase on their alpines.
> > >
> > > Regards
> > >
> > > David
> > >
> > > Louis & Laila wrote:
> > > >
> > > > In addition, Swaymar Race Engines of Leatherhead built a 1725 up to
> 1922cc
> > > > and installed it in a Rally Escort. It produced over 200HP! The reason
> was,
> > > > that it was cheper to get those horses from a Rootes motor than it was
> to
> > > > get it from the Ford! (Irony!)
> > > > As a side note, they bored the block out and had it sleeved. At least
> one
> > > > guy I know just bored the block out and fit the pistons in! That works
> out
> > > > to an 86.1mm piston, as opposed to the stock 81.5.
> > > > if you are remotely curious, 1725 pistons come in come various
> overbores,
> > > > 40,60, and 90 thou! this works out to 1775, 1789, and 1823. The 1922
> engine
> > > > uses pistons from a 1500 Avenger, though the block requires skimming
> since
> > > > the deck height is lower.
> > > > ----- Original Message -----
> > > > From: <sosnaenergyconsulting@home.com>
> > > > > And there's an article on the Ginetta G21 which used a Holbay-ized
> > > > > Rootes 1725 engine! I don't normally think of other british car
> > > > > manufacturers raiding the Rootes parts-bins for their cars (although
> the
> > > > > Davrian comes to mind--but I think they started with the whole imp)
> so
> > > > > it was nice to see that Ginetta's builders felt they could get
> something
> > > > > good from Rootes!
> > > > >
> > > > > Regards
> > > > >
> > > > > David Sosna
> > > > > 65 s4 GT V-6
> > > > >
> > > > > Fritzwich117@cs.com wrote:
> > > > > >
> > > > > > Here you go, boys and girls...
> > > > > > Check out the February 2001 issue of Classic & Sports Car
> Magazine.
> > > > There's
> > > > > > a great article on the Shelby V8s - AC Cobra, Mustang GT 350 and
> the
> > > > Tiger.
> > > > > > All you adrenaline pumpin', hi-revin' motor heads will love this
> story.
> > > > > > ...Rich
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