[net.auto.tech] Oil burning and piston rings

guzman@ttidcb.UUCP (Marc Guzman) (11/02/85)

< who is for dinner >

	My `79 Plymouth (Mitsubishi) Champ, with ~92k miles, emits a puff
of grey smoke when I shift. Oil consumption has gone up also. This obvious
pollution bothers me. My question is, what is the most cost effective
solution that will last around ~25k miles. Some possible solutions :

	1) Poor some kind of gunk into the oil that 'fills and seals
	   scratches'. I imagine this just postpones the problem for
	   a short time.

	2) Replace the rings. Is this job too tough to do myself?
	   Should other things be replaced at the same time? Are
	   they a hassel to replace. Can this sort of stuff be done
	   with the engine still in the car. The Champ is fwd, with
	   a transverse engine.

	3) Replace the engine with a used, rebuilt, new engine?

	4) Replace the car.

Seems to me, that solution 2 or 3 is probably the way to go. Any comments.
Thank you in advance.


p.s.	I realize the unburned hydrocarbons from the oil, may have
	fried the converter, but that's a different problem.

p.p.s.	While searching for a new car to replace my wife's `75 Honda, I
	found that the Champ is very reliable, economical, coffin.
	In both the NHTS(?) crash tests, and the Highway Insurance
	Loss Data, the Champ and it's identical twin, Dodge Colt, have
	very poor scores. This means deadly in a crash.

ins_aeas@jhunix.UUCP (Earle A .Sugar) (11/03/85)

> < who is for dinner >
> 	My `79 Plymouth (Mitsubishi) Champ, with ~92k miles, emits a puff
> of grey smoke when I shift. Oil consumption has gone up also. This obvious
> pollution bothers me. My question is, what is the most cost effective
> solution that will last around ~25k miles. Some possible solutions :
> 	1) Poor some kind of gunk into the oil that 'fills and seals
> 	   scratches'. I imagine this just postpones the problem for
> 	   a short time.
Yup, and probably could cause increased wear elsewhere if it is merely 
an oil thickener.
> 	2) Replace the rings. Is this job too tough to do myself?
> 	   Should other things be replaced at the same time? Are
> 	   they a hassel to replace. Can this sort of stuff be done
> 	   with the engine still in the car. The Champ is fwd, with
> 	   a transverse engine.
Forget it.  With fwd, your trans/diff case is under the engine.  To change 
rings, you have to pull the pistons.  In a normal car, this means pulling the 
heads and dropping the oil pan so that you can undo the connecting rods and 
pull the pistins up and out.  With fwd, you cannot pull the oil pan to gain 
access to the connecting rods without removing the engine from the car.
Is it possible that the oil leak is occuring through the heads (valve 
guide wear?)?  if this is so, pull the head, take it to a machine shop that 
specializes in head work, and have the worn parts replaced.  While you're 
there, have them do a porting job which will give you better power and 
fuel efficiency.  From what you describe above, valve guide wear seems to 
be the culprit, rather than ring wear, because the smoke occurs at times 
of high cylinder vaccuum (during shifts when you suddenly close the throttle),
rather than a constant smoke (which is more indicative of ring wear).
> 
> 	3) Replace the engine with a used, rebuilt, new engine?
This is not a vintage Mustang that you're talking about.  A Champ is hardly 
worth the price of a rebuilt engine (>$1000 if you don't install it yourself).> 
> 	4) Replace the car.
This may be the best long-term solution.  Maybe you can get yourself a car 
that might be worth rebuilding in the future, like one of those new Mustang 
convertibles, or a Corvette.  Or maybe something more down to earth like 
a Taurus (that new Audi-esque Ford family sedan).
> Seems to me, that solution 2 or 3 is probably the way to go. Any comments.
4 is probably your best bet, especially with the promos to sell remaining 
'85 models (8.8% loans, etc.).
-- 
______________________________________________________________________________

Earle A. Sugar
Disclaimer:"I doubt anyone else here agrees with me."
          USENET: ...!seismo!umcp-cs!aplvax!aplcen!jhunix!ins_aeas
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	  BITNET: INS_BEAS@JHUVMS (as a last resort)
	  or call 301-889-0815 after 6 P.M. EST

gvcormack@watmum.UUCP (Gordon V. Cormack) (11/04/85)

It is not hard to replace the piston rings at home.  You need a
socket set, a torque wrench, a ring compressor, and drive-on ramps
(or a jack and axle stands).

To change the rings you must remove the oil pan and cylinder head.
The oil pan can usually be removed with the engine in the car.
If this is the case, you can do the whole job with engine-in-car.
In order to remove the head you must either disconnect the manifolds
from the head, or disconnect the exhaust pipe and hoses and remove
the head/manifolds/carb as a unit. 

Disconnect the bolts that hold the piston rods to the crankshaft.
Then remove the lower half of the bearing and push the piston and rod
out the top of the engine.  Remember which side of the piston faces
the front of the car, and replace the bearing half on the same piston
rod.

Remove the rings from the piston and scrape all traces of carbon from
the grooves.  I use a broken ring as a scraper.  Install new rings on
the pistons, oil them, and put them back in the cylinders using a
ring compressor.  Replace the piston-rod bearings on the crankshaft,
replace the oil pan, replace the head (using a torque wrench and a
new gasket).  Fill the crankcase with oil and you are done.

How long does it take?  The last 2 cars I did at home (a 76
Mazda 808 and a 76 Honda Civic) took about 8 hours each.
(these are estimates only; your time may vary due to ... ...).
In each case the oil consumption went from  >> 1 qt/200 mi to
<< 1 qt/2000 mi.  Each cost << $100 in parts.


What else might you do while you have the engine apart?  You might
take the head to an auto store or machinist to have the valves ground.
I would do this only if there is evidence of faulty valves.  You
might want to replace the connecting rod bearings.  These cost $20
to $50.  Before disconnecting them, try to wiggle them up and down.
If there is a ticking noise caused by movement, replace them.
Many people say you must hone the cylinders before replacing the
pistons.  I think honing is not necessary in most cases, and is not
a good idea in the home environment.  Honing creates metal particles
that can easily permeate (and destroy) your engine.  Also, if
you aren't careful, you can easily make your cylinders too big, requiring
oversized pistons and rings.

bcbell@inmet.UUCP (11/05/85)

** oil lines **

I suspect it's blowing oil by the valve guides.  Doesn't sound like rings.
Don't gunk up your engine with oil additives.  Rebuild is probably gonna
cost more than the car is worth.

The most expedient solution is probably to do nothing.  The car will probably
last the miles you want out of it anyway.  Buy a case of cheap oil, then
drive it into the ground.

R.M. (love your car) Mottola
Cyborg Corp.
Newton, MA.

(Reply posted for me by a friend)

hakanson@orstcs.UUCP (hakanson) (11/07/85)

Please bear with the inclusions -- I've tried to keep them short.

>/***** orstcs:net.auto.tech / jhunix!ins_aeas / 10:11 am  Nov  3, 1985*/
>> < who is for dinner >
>> 	My `79 Plymouth (Mitsubishi) Champ, with ~92k miles, emits a puff
>> of grey smoke when I shift. Oil consumption has gone up also. This obvious
>> pollution bothers me. My question is, what is the most cost effective
>> solution that will last around ~25k miles. Some possible solutions :
. . .
>> 	2) Replace the rings. Is this job too tough to do myself?
>> 	   Should other things be replaced at the same time? Are
>> 	   they a hassel to replace. Can this sort of stuff be done
>> 	   with the engine still in the car. The Champ is fwd, with
>> 	   a transverse engine.
>Forget it.  With fwd, your trans/diff case is under the engine.  To change 
>rings, you have to pull the pistons.  In a normal car, this means pulling the 
>heads and dropping the oil pan so that you can undo the connecting rods and 
>pull the pistins up and out.  With fwd, you cannot pull the oil pan to gain 
>access to the connecting rods without removing the engine from the car.

Boy are you gonna be surprised.  On the Champ/Colt, and probably some
other fwd cars, the transaxle is mounted on the end of the engine, partly
below and behind it.  The oil pan is fairly accessible, once you take off
the belly pan (I haven't done it, but I have looked at it some).

>. . .  From what you describe above, valve guide wear seems to 
>be the culprit, rather than ring wear, because the smoke occurs at times 
>of high cylinder vaccuum (during shifts when you suddenly close the throttle),
>rather than a constant smoke (which is more indicative of ring wear).

Seems reasonably possible.  My suggestion would be to drive it 'til
the oil consumption is unbearable, then trade it in on another one.
There's quite a market for used Champ/Colts, even with >100k miles
on them.  Anecdote time:  While getting my '80 Colt fixed up with
new brake pads (@ 84k, first time) & repacked wheel bearings, the
Chrysler mechanic told me they get a fair number of these cars with
more than 90-100k miles on them.  When they're traded in, they can
sell them right away.  He also said one fellow had an '83 with 103k
on it, and had never done anything to it but change the oil, if that.
He brought it in to have a rear wheel bearing replaced because they
had never been repacked, and to have the valves adjusted for the first
time!  He also had the carb rebuilt.  So it seems you can get more than
your money's worth out of these cars, even if you abuse them.

Once you've got the head off, you might as well do the rings as well.
Getting the head off is likely to be a major task, anyway.  The head
bolts are the kind that take a large hex-key to remove (this IS 
net.auto.TECH, after all :-).

>. . .  A Champ is hardly 
>worth the price of a rebuilt engine (>$1000 if you don't install it yourself).> 
Obviously I disagree.  I'd like to be able to just throw the thing
away with impunity when it's shot, but I just like the car too much
to do it painlessly.  Well, it doesn't have to be done soon -- I figure
I've got another 20k before I have to bite the bullet.  But parts
are certain to be fairly expensive.  Sigh.  But the new ones are
improved -- and more complicated and harder to work on.  Sigh again.

>
>Earle A. Sugar
>Disclaimer:"I doubt anyone else here agrees with me."
>          USENET: ...!seismo!umcp-cs!aplvax!aplcen!jhunix!ins_aeas
>          CSNET:ins_aeas@jhunix.csnet
>          ARPA:ins_aeas%jhunix.csnet@csnet-relay.arpa
>	  BITNET: INS_BEAS@JHUVMS (as a last resort)
>	  or call 301-889-0815 after 6 P.M. EST
>/* ---------- */


Marion Hakanson         CSnet:  hakanson%oregon-state@csnet-relay
                        UUCP :  {hp-pcd,tektronix}!orstcs!hakanson

davidsen@steinmetz.UUCP (Davidsen) (11/14/85)

In article <317@watmum.UUCP> gvcormack@watmum.UUCP (Gordon V. Cormack) writes:
>It is not hard to replace the piston rings at home.  You need a
>socket set, a torque wrench, a ring compressor, and drive-on ramps
>(or a jack and axle stands).
>

There was a lot of good advice in this message, but there is one tool which
probably will be needed, a ridge reamer. By the time a ring job is needed, a
ridge usually builds up at the top of the cylinder. This should be removed
before trying to remove the piston from the block. use of force to get the
piston out may break the old rings (no big deal) or damage the ring groves in
the piston (ouch).

I also recomment using plastigage to measure the bearing clearance rather than
"shake it and see if it sounds loose". This is available at good auto stores,
and costs only a few bucks.

Before removing the rods the bolts should be wrapped with masking tape or
should have pieces of old rubber hose put on them. This prevents maring the
crankshaft as the rods go in or out.

Good luck with your ring job!
-- 
	billD	(..seismo!rochester!steinmetz!crdos1!davidsen)
		(davidsen@GE-CRD.ARPA)

"It seemed like a good idea at the time..."

bcking@inmet.UUCP (11/23/85)

** wring job **

One other caution.  Make sure the rod bolts clear the piston bore
when you're pounding them out!  Pistons are in there pretty tight
and sometimes it doesn't go any further, but you just keep pounding
until it comes out, only to find that a rod bolt hooked the bottom
of the bore and took a big chunk out of the block.  Be careful.

R.M. Mottola
Cyborg Corp.
Newton, MA.

(Response posted for me by a friend, but not for long)