Re: [AMC-list] IT RUNS.

[Jim Blair <carnuck@xxxxxxxxxxx>]

The FWD V6s changed to 3.0 and 3.3 (that motor didn't last long at GM and AFAIK only Buick and Pontiac got them) before it was replaced. The rod bearings in the early 2.8 (same ones AMC got till '86) had rod bearings that were too narrow to deal with any wear, causing many to self ventilate and self destruct as well.
   I have an '88 Celebrity with the 2.8 (crate motor) that I am pulling apart to put the motor and EFI into my recently purchased '86 Comanche (so my room-mate will have 4x4 before next winter. Wifey gets the '82 Spirit turned into an Eagle which should be done about the end of June)
   So much going on and somehow in the mix I have to spend more time with my Mom who found out day before Mother's Day she has inoperable lung cancer (too close to the heart) Chemo and radiation can't be done either.


From: adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)
To: amc-list@xxxxxxxxxxxx
Subject: Re: [AMC-list] IT RUNS.
Message-ID: <201005110247.o4B2lD203181@xxxxxxxxxxxxxxxxx>
 
" 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 		 	   		  
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