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

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

welcome aboard!

" From: 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.

black exhaust sounds like the choke is sticking.  you could also need a
general tuneup.

if the motor is running very rich, the cat could be running very hot and ready
to melt down if it hasn't already.  and a plugged cat wouldn't help your loss
of power.

" 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. 

many of us have discovered there's no substitute for the factory svc man.  it
often covers more, in more detail, and errors have been found in others.

"  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.

normally you disconnect and plug the vac advance line when setting base
timing.

" 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.

when you say 'loose', do you mean rattly-about-to-fall-out, or merely able to
spin between fingers?

" 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...

i'm wondering if you have the rockers too tight to start with.  if the valves
are never closing, that would explain why that bank is cold.

you could also try 'gunk' brand motor flush in the oil.  if the po hasn't been
good about oil changes there could be a lot of crud in the oil system and that
could be preventing your lifters from pumping up.  i've had good luck with it,
but ymmv.

" 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?

maybe that carb just needs a good cleaning and/or rebuild.

do you have emissions checks up theyah in maine?

you could swap an entire injected s-10 2.8, or for even more power a camaro
3.4.  i believe a neutral-balanced ['88-up] s-10 flywheel will work; i know the
camaro one is too thick, and pre-'87 2.8s - jeep and gm - are externally
balanced, so the original 'wheel can't go on the newer mill.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh@xxxxxxxxxxxxxxxxx                       and think what none thought
_______________________________________________
AMC-List mailing list
AMC-List@xxxxxxxxxxxx
http://www.amc-list.com/mailman/listinfo/amc-list

or go to http://www.amc-list.com