[Shotimes] Rod Bearing Change @190K miles

[Ron Porter]

Actually, the MTX is at 2K at 55 mph in 5th. I would never get into 5th
until at least 55 mph in any of my MTX SHOs.

As SHO folks have learned when they put oil pressure gauges in their cars,
these high-volume, low-pressure oil systems have very low pressure at lower
rpm. A few chugs and a ping or two will pound the bearings at those low
rpms.

I have held to the "2K Rule" in manual tranny cars for many years, and I
still fell it is the best policy.

Ron Porter

-----Original Message-----
From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
On Behalf Of Jim & Debbie Leyden
Sent: Wednesday, February 01, 2006 9:44 AM
To: 'Donald Mallinson'; 'bjshov8'
Cc: shotimes@autox.team.net
Subject: RE: [Shotimes] Rod Bearing Change @190K miles

I think part of the problem here is the lack of a good definition of
"lugging".  When I was in the military and going through Machinery
Technician Class A school they defined lugging as a condition where
application of more throttle will not increase engine speed.
There seems to be some confusion about the SHO motor as to what a safe RPM
is to run at on the lower end of the scale.  Some people are claiming that
running the motor at less that 2000 RPM is lugging it.  I dispute that
premise based on the factory owners manual and the fact that when the car
was built the national speed limit was 55 MPH.  In a SHO MTX 55 MPH in 5th
gear is less than 2000 RPM.  This tells me that it is perfectly acceptable
to run a SHO motor at less than 2000 RPM.  I believe that the ATX cars will
run as low as 1500 RPM before forcing a downshift under light throttle
conditions.
The problem as I see it is when a driver applies excessive throttle to bring
the RPM up from 1500 RPM to whatever speed they are looking for.  I think
that is what is being called lugging and in truth has nothing to do with
lugging at all.

Jim




-----Original Message-----
From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
On Behalf Of Donald Mallinson
Sent: Wednesday, February 01, 2006 9:07 AM
To: bjshov8
Cc: shotimes@autox.team.net
Subject: Re: [Shotimes] Rod Bearing Change @190K miles

At least that guy was making about 300lb ft of torque at 1500 rpm!

I sold a generation 1 Mazda RX7 to the secretary in my insurance agents 
office.  When she took it for a test drive, she handled the clutch OK, 
but shifted to high gear at about 25 mph and in a rotary that is 
horrible!  I cautioned her that this engine needs rpm, and never to 
drive around below 1500-2000 rpm.  That is pretty safe with most engines.

Understand that the definition of lugging is about FIVE HUNDRED rpm!

Well, I kept seeing her drive around town with the thing popping and 
banging at 25 mph in high gear, again about 500 or so rpm at big 
throttle openings.  I called her a couple times warning her that rotary 
experts say she is going to ruin the engine, and sure enough within 2 
months she calls asking me to help her get a new engine.  I did better.  
I found an enthusiast to buy the car and he put in a used engine.  This 
was about 15 years ago and he is still racing that car!

Don Mallinson

bjshov8 wrote:

>OK, I've got a story about "lugging" engines.
>When I was working at my dad's shop back in the early 70's, we had a friend
>who was a plumber, and had a 1968 Chevy pickup.  He special ordered a 1966
>Impala SS for his wife, with 425hp 427 and 4-speed.  His wife didn't like
>driving it so my dad's shop swapped the engines between his pickup and
>Impala.  The Impala ended up with a 283 and Powerglide, the pickup ended up
>with the 427 and 3-speed trans.  I don't know what happened to the 4-speed.
>But back to the subject- this guy would drive that pickup around town,
never
>getting above 1500 rpm.  In 1st or 2nd gear, he would get to maybe 1500
rpm,
>then he would drop into the next gear and chug along.  I always thought
what
>a waste.
>
>
>  
>
>>It is NOT impossible to lug an ATX, and (unfortunately) I have talked to,
>>and ridden with, SHO owners who do just that.
>>    
>>
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>.
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