Re: [AMC-list] IT RUNS.

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: Matt Haas <mhaas@xxxxxxx>
" 
" It is the 2.8 (same one AMC used for a couple of years in the 
" Cherokees), 3.0, and 3.3 liter 60 degree V6's that have this problem. I 
" don't know if GM still uses this engine or not but to the best of my 
" knowledge, they never fixed the problem (this engine family has had lots 
" of problems from day 1). The whole intake manifold arrangement is just 
" stupid. Besides being bad for leaks, you also have to pull the push rods 
" to change the gaskets which adds to the cost of the repair.

iirc the chev 60-deg family never had 3.0 or 3.3 members; it was
stroked into a 3.1 then bored into a 3.4, then evolved into the
current 3.5/3.9 'hi value' engine family, still pushrod.  there was
also the 3.4 twin-dual-cam/dohc, intended for the fiero but came out a
year after it was cancelled.  the 3.9 is up to 240 hp.
the intake problem is b/c they're so narrow compared to a 90-deg
engine; it would've been pretty near impossible to put a carb atop an
intake squeezed between full-width heads and get good airflow or
mixture distribution.  it's possible the hi value engine rectifies
this.

there's an unrelated 60-deg aluminum ohc [dohc?] made in various sizes
from 2.8 to 3.8, incl 3.0, 3.2, and 3.6, and it's used by alfa and
now-independent saab, legacies of gm days.

" The 3.8 liter 90 degree V6's (especially the 3800 Buick motor) are 
" pretty good V6's. The Chevy design 3.8 is I think a 305 with two 
" cylinders hacked off. It's not a true even fire design (even the so 
" called even fire one doesn't fire every 120 degree) which makes it run a 
" little rough. That issue seemed to be fixed when it grew into the 4.3 
" liter V6. Dad's Astor (4.3 V6) was pushing 200,000 miles when he got rid 
" of it and it was still running strong.

these are all derived from successful v8 designs, the 300/340/350 iron
version of the aluminum buick 215 and the sbc.  the buick was made in
lots of sizes including a 3.0 and iirc 3.3.  iirc the chev 229/3.8
crank was set to make each -bank- an even-firing 3, probably to aid
even induction and scavenging.  they have the advantage of room
between the banks for the intake.

curiously, the 2.8/hi-value family shares some dimensions with the
sbc, bore centers and bearing diameters, and originally conrod
lengths.  i wouldn't be surprised to find deck heights were the same
also.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh@xxxxxxxxxxxxxxxxx                       and think what none thought
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