[Shotimes] Rod Bearing Change @190K miles

[Mark Nunnally]

Actually I think the opposite, In my experience (probably not a good "slice" of the whole pie, but none-the-less) the ATX motors seem harder on the bearings.  Throwing the "lugging" thing aside, the 3.2L makes 7% more torque, which is essentially a more forceful downward stroke at any given rpm, on the same bearing size/radius/surface area.  Also the rod/pin/piston assembly is heavier in the 3.2L, so you've got extra weight the bearing has to contend with as well.

And I think at moderate driving the ATX, although it may not "lug" (that's a relative term) does keep the revs pretty low, at least below the 2k "magic" number the SHO likes to be above for decent oil pressure.

mark



-----Original Message-----
>From: bjshov8@comcast.net
>Sent: Jan 31, 2006 11:04 AM
>To: shotimes@autox.team.net
>Subject: Re: [Shotimes] Rod Bearing Change @190K miles
>
>There has been speculation that the ATX does not allow the engine to "lug", and therefore reduces wear on the bearings.  With an MTX you can run the engine under load at real low rpm's which is what is theoretically bad for the bearings.
>
>
>>  Just changed the connecting rod bearings at 190K miles on my wife's 1993 ATX.
>> I think it was a waste of time! The bearings had very little wear. I just
>> could not believe how clean the engine is! Only had a small oval patch of
>> copper showing, maybe 1.5 or 2 inches long. Not even all the way across the
>> bearing shell. We have had this car since 78K miles and have only used Mobil 1
>> synthetic oil, changed at 5K intervals. The new rod bearings checked with
>> plastiguage were right in the middle of the factory clearance range.
>>  Maybe the ATX SHO's can go without changing the rod bearings? Even up to and
>> over 200K miles?
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