[AMC-List] 1986 Jeep Cherokee clattering valves and black smoke

[Howard.Allen@xxxxxxxxxxxxxxxxx]

Hi;
I am a new member located in Limington Maine.  I have owned one other AMC 
product  years ago, a 1973 model I bought non running for $50.  Ran it for 
6 months with a slippling clutch and sold it for $25.  Nice engine never 
smoked.  Anyway, this week I purchased a non running 1986 Jeep Cherokee 
with a 5 speed transmission and 2.8L V6 engine.  I replaced the fuel pump 
and installed a new radiator and battery and started it up.  Hasn't run 
for about 5 months.  Started a little hard but it ran.  It sounded like a 
sewing machine but the oil pressure was 40PSI so I let it run a while.  As 
it warmed up it ran slower and slower so I cranked the mechanical throttle 
stop up to compensate for the time being.  AFter 15minutes the oil 
pressure was down to 15PSI and the exhaust was black and RPM were down to 
550 with the mechanical throttle stop all the way out.  It finally stopped 
running.

I decided to look for the cause of the valve noise and removed the right 
valve cover where most of the noise was comming from.  I found that the 
valve cover was dented and could see marks from the rocker arm hitting the 
dent.  I straightened this problem out and checked the valve lash using 
the procedure in the trusty Haynes manual I bought.  I discovered that all 
the pushrods were loose and the rockers accordingly.  Following the Haynes 
procedure I first tightened the hold down bolt until the pushrod wouldn't 
turn with finger pressure, then tightened the rocker bolts 1.5 turns.  I 
restarted the engine and it did not sound any better.  I changed the oil 
to 20-50 and replaced the stupid oil filter (thanks GMC!!).  I restarted 
the engine and let it warm up again, drove it a little in the driveway and 
noted that it has very little power, stalling it a number of times in 
first gear while trying to turn it around on a little hill. 

 I checked the timing and found it off the mark (couldn't even see it) so 
I loosened the distributor clamp and turned it until I could see the 
timing mark.  The manual said nothing about disconnecting anything so I 
assume you just adjust the base timing in the normal fasion.  Setting it 
to the factor required 16BTDC the engine slowed down so much I could 
barely keep it running even with someone inside with their foot on the 
accelerator.  Something is obviously not right here.  Park it for the day.

Next day it will not start.  Tries, but will not stay running.  AFter 
running down the battery and playing with the distributor position I 
checked the exhaust manifolds.  THe left side was quite warm but the right 
side (the side I did the valve lash adjustment) was just barely warm.  SO 
I take the valve cover off again and check the valve lash again.  Most of 
the pushrods are loose so I again readjust them.  Keep in mind that I have 
now tightened the rocker arm hold down nuts three turns from their 
original positions several days ago.  I turned the engine over manually 
after removing the plugs and watched the rocker arms.  They all move up 
and down about the same distance with one exception which I recheck and 
find OK.  It started to rain so I did not attempt to start it up.

I would like to know why the rockers needed readjustment again, does it 
seem likely the hydraulic lifters are all collapsed?  Does it seem 
reasonable that this problem is related to the black smoke, poor idle (and 
sooty spark plugs)??  I was told by the PO that this engine ran fine other 
than "leaking a little oil"  (gushing would be my description, the rear 
seal is shot!!).  I have not checked compression yet, wanting to get the 
valve lash taken care of first.  I have also not attempted to adjust the 
left valves because I wanted to make sure I was doing it right in the 
first place...

Any ideas or experience with this engine and problem would be appreciated.

Also, does anyone have any opinions on replacing the carb (2ESE Rochester) 
with something better/less complicated and more reliable?

Best Regards
Howard Allen
S. Portland, Maine

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