Engines warm up differently

"I have come to the conclusion

"I have come to the conclusion that the port engine, which is a replacement long block, is much better than the starboard engine, which was rebuilt. This was done by the previous owner. The starboard engine comes up to temperature in a few minutes were the port engine takes twice as long. Since these are closed loop cooled the only explanation I have is that the rebuild engine runs much hotter due to engine component tolerances. Does anyone have an opinion on this observation. The rebuilt engine runs hot under load (175 to 190) but at 160 (thermostat setting at 1500 rpm). What else would cause an engine to warm up fast?
Jeff"

"A t-stat that's leaking f

"A t-stat that's leaking fluid past it, or is simply defective. (That rebuilt engine is also running a bit too hot.) Closer tolerances have nothing to do with it--if they did, it would have seized long ago.

Jeff"

"Usually on a twin one engines

"Usually on a twin one engines is hooked up to the hot water heater and takes 3 times as long to warm up, could that be the case?

Dan"