🚀 go-pugleaf

In article <314@g.cs.cmu.edu.ARPA>, mjs@g.cs.cmu.edu.ARPA (Mark Stehlik) writes:
> In response to Mark Stevans's questions about snows:
> 
> > I have 225/60HR14 Dunlop radials on my Toyota Supra right now, but, since
> > winter appears scant hours away here in northwestern New York State, I
> > solicit advice on what to do about snow tires.
> > 
> If I were in your position, I would DEFINITELY invest in set of steel wheels
> and purchase the appropriately-sized 70-series snows.  I am not convinced that
> a 60-series profile is what you want in a winter tire.
> 
In snow, narrow tall tires are best. The narrower the tire, the
more bite they will have into snow, since the weight on each tire
will be distributed over a smaller contact patch. Tall tires help
raise your car and give you improved ground clearance.

Of course your car's aerodynamics suffer and it's ability to hold
corners will drop like a rock!
-- 
					Jack Saltiel
					Cambridge Digital Systems
					{wjh12,talcott}!cdstar!saltiel

	"Here's to plain speaking and clear understanding."
	"I like a man who likes to talk."

> In snow, narrow tall tires are best. The narrower the tire, the
> more bite they will have into snow, since the weight on each tire
> will be distributed over a smaller contact patch. Tall tires help
> raise your car and give you improved ground clearance.
> 					Jack Saltiel

Not true.  Two tires with the same pressure will have the same
contact area.  The wide tires will have a wide, short contact
patch while the skinny tires will have a longer patch.  Which is
more desirable is a difficult question to answer.

Other than increasing pressure (which I heartily recommend), the
way to get higher contact pressures is to choose a tire with an
open block tread design and heavy belts.  If, for example, only
half of the contact area has tread (the rest is grooves), the pressure
on the parts of the tread contacting the ground is double that of
an untreaded (slick) tire.

I quit using snow tires about 10 years ago.  Instead, I choose a
steel-belted radial with a tread as described above (all-season
radials don't meet my criteria).  Some tires I have had are
  Uniroyal 180, Can. Tire Supreme (european sized), Michelin TRX.
These were all wonderful.  I have never been stuck in snow that was 
shallower than the underbelly of the car.  Even in much deeper snow,
I have done pretty well.  During the 10 years I have lived in
Winnipeg, Montreal, and Waterloo, so I think I have seen as much
snow as most readers are likely to.

As long as there seems to be interest in my snow tire dilemma (my life is
so exciting!), I'd like to, shall we say, "sharpen" the debate:

As Jack Saltiel says in the referenced article:

> Tall tires help raise your car and give you improved ground clearance.

That would be extremely valuable, but the wheel wells on my Supra (even though
the springs are still strong) only clear the tire by about an inch, so I
can't put taller tires on the car.  I can only vary the width and tread here.

Jack also says:

> In snow, narrow tall tires are best. The narrower the tire, the
> more bite they will have into snow, since the weight on each tire
> will be distributed over a smaller contact patch.

This makes a lot of sense, but wider tires would put more cross-tread against
the snow.  I imagine this would improve traction.  Considering the logical
extremes, inch-wide tires would work very poorly on snow and ice.  Yet, I'd
imagine that ten foot wide tires would work great, assuming they held onto the
rims and I stayed in the center of vacant three-lane highways :^).  Since the
Supra is a reasonably heavy car, at 2886 pounds, I'm not sure narrower tires
would be better.  If loading the car would help, John M. Sellens recommends
sandbags.  Any opinions?  Comments?  Jokes?

All concerned seem to agree that salt will kill my alloy mag wheels.  Thanks
for the info.  I figure I'll pick up three or four steal wheels, and four
completely non-matching hubcaps.

One mail respondent strongly disrecommended the Goodyear Eagle Mud and Snow
tires.  He said they were nearly useless for traction.  As you can see,
the Eagle M ans S tread design is somewhat simpleminded:

No, after four tries, I find myself no graphic artist.  To put it into a
thousand words, it just has inch-wide treads running the width of the tire
alternating with 3/4 inch wide gaps.  The treads are also cut to provide a
1/2 inch gap running parallel to the direction of motion every two inches.
Isn't it better to have some zigzags?

> Considering the logical
> extremes, inch-wide tires would work very poorly on snow and ice.  Yet, I'd
> imagine that ten foot wide tires would work great, assuming they held onto the
> rims and I stayed in the center of vacant three-lane highways :^).

I assume that "works great" assumes that you are driving a toboggan.  I think
that you would always go down hill.  The faster you 10 foot tires rotated up hill
the faster you would go down hill since you would create that nice low friction
layer.

< 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.

> < 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

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.

	I would like to know if anybody know how to
reset the sensor on a nissan sentra. It came on at 30,000 mile and is quite
annoying. Please just post it on the net.



				Thanks in advance for the help


=============================================================================
				   from the office of the mighty 
		
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					Lynn E. Gurske
					ECS/mfg  Tektronix
					Wilsonville, OREGON 97070
					60-640
=============================================================================

Reply-To:
Keywords:which sensor

In article <951@mako.UUCP> lynng@mako.UUCP (Lynn Gurske) writes:
>	I would like to know if anybody know how to
>reset the sensor on a nissan sentra. It came on at 30,000 mile and is quite
>annoying. Please just post it on the net.

	Which one?????????????????????

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..."