OK then I stand corrected. The drawing did not show the opposit angled
in-line valves of that head. It really did appear to look like any normal
chamber from that drawing. See ing "flat" in line valves means there can't
be a hemi shape, but as you stated, if there is a North South angle
configuration then there can be a hemi shape, and I stand corrected. ALL
hemi shaped head engine I have worked on have all had the standard wide head
opposing valve set up. I have never seen one of the Aussie configuration.
It is intersting.
The last Honda Road racer that I built, had the standard Hemi head setup
and with the huge Yoshimura cam, and manly SS valves wich were opposing of
course..it was quite a thrill to build. And kind of scarry too. had to
have some very stiff valve springs wich 110 pounds (US) of seat preasure,
because at maximum vallve overlap, the valves would pass each other within
50 thousands of an inch.. A 0.050 feeler gauge would rotate both valves.
\ / and turning upto 15,000 rpm, there was little room for error. it
lasted two season as I remember, and broke a rod launching a piston right
into the head..oh well..At least I wasn't riding it.
Anyway, like I said. I stand corrected.
Rich
BTW I didn't actually ask anything about the rods. that was someone else.
I just jumped in about the hemi head picture I saw.
-----Original Message-----
From: RAKICH Paul <paul.rakich@wrc.wa.gov.au>
To: 'Rich Atherton' <gumby@connectexpress.com>
Date: Tuesday, January 18, 2000 12:57 AM
Subject: RE: 265 Chrysler Rods
>Rich
>
>The point I was trying to make was that you do not need to have opposed
>valves (at 90 deg. or otherwise) and a centrally positioned spark plug to
>have a (true) hemispherical combustion chamber as is the case with the 265
>head. The orientation of the valves and the spark plug position in the head
>has absolutely no bearing whatsoever on the combustion chamber shape. With
>the 215/245/265 engines (as you can see in the attachment I sent
previously)
>the valves are positioned in-line at the top of the combustion chamber and
>the spark plug is positioned to the side of the chamber. As you correctly
>stated, the valves are positioned in-line similar to the 225 slant six. On
>close inspection of the cylinder heads it can be seen that the combustion
>chamber shape is in fact truely hemispherical (it looks EXACTLY like half a
>circle) - with the valves orientated in a straight line. Unbeleviable - but
>true!! In order for the valves to align to the correct shape of the
>combustion chamber they are canted slightly opposing one another as you
>suggested - which is not apparant in the illustration. Instead of the
valves
>being orientated east-west they are positioned north-south. This
arrangement
>allows the fitment of a narrow rocker instead of a wide one as used on most
>other hemi motors with opposed valves and still preserves the integrity of
>the hemispherical combustion chamber shape. What it boils down to is this -
>you can have a true hemispherical combustion chamber without the spark plug
>at the top and the valves at opposing points in the head. I'm truely sorry
>if you have trouble accepting this fact but the Australian Hemi 6 head is
>living testimony to this!
>
>It all seems to me that this a far cry from you original enquiry regarding
>the suitability of the 265 hemi rods for the Buick/Rover 215 V8 engine. All
>you really need to know is that the rods from the 265 engine will fit the
>Buick and if you want some you'll have to get them from Australia mate!!
>
>Happy Hunting
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