red95gts
06-26-2002, 03:12 PM
As some of you saw last night on IRC, I was having a problem with the pilot bearing for the 347 motor I'm building.
The bearing the car's owner brought me was a "Motor-Mite" brand from Auto Zone. Depth (as marked on the package) was .733". We pound it into the crank and it stops about a 1/4" short of being flush with the end of the crank. "Hmmmm...that can't be right...," we think. We pull it out and measure the depth of the "counterbore" in the end of the crank.... .465"
The crank is a cast Eagle ESP 3.400" stroke unit from BB&T. Called BB&T about the problem. They didn't know but were able to provide me with a good phone number to Eagle. So, I call Eagle and here's where the discovery is made:
The correct bearing for the 5.0 should be approximately .560"-.540" depth, leaving .080"-.100" beyond the end of the crank.
For whatever reason, Auto Zone sells the MotorMite one as the correct one, although it is not. According to the guy at Eagle, if you can get the transmission to bolt up to the bellhousing, it will put so much forward force on the crankshaft, you'll destroy the main thrust bearing.
There is a guy locally that built a very similar short block using the Eagle ESP crank. Within a couple weeks and roughly 1500 miles, it ate the main thrust....I haven't talked with him yet, but I'll bet he used a MotorMite pilot bearing
FWIW, I found the correct dimension in a American-made Federal Mogul bearing at O'Reilly's....it costs a whopping $2.00 more than the Chinese-made MotorMite.
Just a litle FYI!
The bearing the car's owner brought me was a "Motor-Mite" brand from Auto Zone. Depth (as marked on the package) was .733". We pound it into the crank and it stops about a 1/4" short of being flush with the end of the crank. "Hmmmm...that can't be right...," we think. We pull it out and measure the depth of the "counterbore" in the end of the crank.... .465"
The crank is a cast Eagle ESP 3.400" stroke unit from BB&T. Called BB&T about the problem. They didn't know but were able to provide me with a good phone number to Eagle. So, I call Eagle and here's where the discovery is made:
The correct bearing for the 5.0 should be approximately .560"-.540" depth, leaving .080"-.100" beyond the end of the crank.
For whatever reason, Auto Zone sells the MotorMite one as the correct one, although it is not. According to the guy at Eagle, if you can get the transmission to bolt up to the bellhousing, it will put so much forward force on the crankshaft, you'll destroy the main thrust bearing.
There is a guy locally that built a very similar short block using the Eagle ESP crank. Within a couple weeks and roughly 1500 miles, it ate the main thrust....I haven't talked with him yet, but I'll bet he used a MotorMite pilot bearing
FWIW, I found the correct dimension in a American-made Federal Mogul bearing at O'Reilly's....it costs a whopping $2.00 more than the Chinese-made MotorMite.
Just a litle FYI!