[Supras] Auto Trans & Oxygen Sensor Questions

[Christian, Skip]

Joe,

	I think the only reason my torquing the head bolts worked was
that my head gasket was only two weeks old.
	304K !!!  Congratulations !  Your's is the record so far.

Thanks, Skip 

-----Original Message-----
From: Bigmacz28 at aol.com [mailto:Bigmacz28 at aol.com] 
Sent: Thursday, May 15, 2008 13:53
To: Christian, Skip; supras at supras.com
Cc: studioartist at yahoo.com
Subject: Re: [Supras] Auto Trans & Oxygen Sensor Questions

Have a 89 that went 304K before rod bearing gave up. Don't know other
history about the car. Oil changes etc....That's when I got it. Replaced
with JDM engine. Guy said he was the second owner and got the car with
about 160K.
 
I had the same problem you did on a 88 but torqueing the head down again
didn't help. Car ran good just some bubbles coming out the radiator
after turning the engine off and would loose coolant over time. I did a
leak down test and three cylinders were doing it. Compression was 170 in
all! Car ran good! The leak was only one way. No coolant in cylinders or
oil. I replaced the engine with rebuilt one last week. After taking the
engine apart the head had lots of pits around the water channels, next
to the cylinders and the block had some trenches around two out of the
three cylinders in question. The head is scrap. The block is at the shop
for cleaning and decking. The range I have seen is between 115K & 145K.
That's about six total and I have two others I haven't looked into yet
but both are in that mileage range.
 
Joe Mac
 
Tucson,Az
 
In a message dated 5/14/2008 10:27:32 A.M. US Mountain Standard Time,
wellner.christian at navy.mil writes:

	Studioartist,
	
	    I wish 300K was possible with the original head gasket.
Mine
	went at around 120K.  When I replaced it, I noticed the block
deck was
	trashed.  Head gasket must have been leaking for at least 30K
miles
	before it let go.  I had only spent $1500 for the car & hadn't
planned
	on rebuilding the engine (other than the head gasket car ran
fine and
	looked good).  So I just stuck on a new head gasket and crossed
my
	fingers.  Two weeks later, I started hearing the famous gurgling
sound
	from the dash (heater core) telling me that the new gasket had
started
	leaking.  Needless to say, I was pissed......  So, I got out the
torque
	wrench, and torqued all the head bolts (in sequence) to 85
ft-lbs.  What
	did I have to loose ?  The "trenches" in the block deck looked
like they
	were deeper than the allowable milling limit.  Anyway, its now
been
	about 100K miles on the same head gasket.  As long as I let the
car
	fully warm up (temp gauge needle about half way up) before I
touch the
	throttle, it uses no coolant !!!  Power is still reasonably
good.  If I
	remember correctly, the gasket is blown on #3 and #4 cylinders.
	    Now, if I can just get the auto trans to stop shifting from
	first straight to fourth.......
	    Really would like to know if anyone has made it to 300K
miles
	without rebuilding the engine bottom end.  Trans internals
should last
	this long if fluid is changed.  Since all 7Ms blow head gaskets,
there
	probably isn't a 7M Supra around that hasn't had a valve job.
When I
	had my head off, I had two valves ground, and all the stem seals
	replaced.  The new stem seals at 120K changed the oil
consumption from 1
	qt every 700 miles to 1 qt every 2500 miles.
	
	Thanks, Skip
	'86 MA70
	
	
	---------------------------------------------------------------
	Original Message
	Date: Tue, 13 May 2008 19:43:26 -0700 (PDT)
	From: LN <studioartist at yahoo.com>
	Subject: Re: [Supras] Supras Digest, Vol 53, Issue 16
	To: supras at supras.com
	Message-ID: <489860.95412.qm at web30406.mail.mud.yahoo.com>
	Content-Type: text/plain; charset=us-ascii
	
	If you can get 300k miles on stock head gasket it would be a
first.
	Mine went to 135k then it was gone.  Hope that answers it.
	
	
	
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