Temperature question with new motor

[01 cummins]

I bought a 94 Monterey 206 5.7GL with 321 hours about 2 months ago and the connecting rod bearing went after only 2 hours of use. The running temp in the 2 hours that I used it was around 140.

I purchased a new complete GM VORTEC 5.7 and just got it hooked up and running. It came with a new temp sending unit and its reading 180 when warmed up. It is pumping water fine and everything ( manifolds, risers, intake) are cool to the touch.

Could there be an issue with the new sending unit and not working with my current gauge? I'd really like the new engine to last longer then 2 hours after all the money and time I've spent on it.

Thanks in advance!

 

[Scott Danforth]

Or you have a different thermostat in the new motor. Was the GM vortec motor sourced as marine or automotive?

 

[01 cummins]

I bought it from a marine supplier Michigan motorz. I used my water neck from the volvo and they sent me thermostat.

 

[Scott Danforth]

You may want to check the temp of the t-stat. However a rule of thumb that I remember is the 140 is used on carbed motors with seawater cooling, 160 for carbs with HX's and 180 for fuel injected motors.