Cross over with low temp has t stat and bypass
 

I have seen many cross over discussions and have read tons of them, but i have not found any with the issue I'm having. Back story on the boat is it was set up with a procharger system on the factory HP500 (carb) when i bought it. I removed the procharger ran the cross over from this kit with a gutted thermostat for 3 seasons and could get temp to 130. I removed this and in stalled the Hardin Kit 620-300100 with bypass and 142 thermostat to get faster oil temp, but can't get water temp to 100 even after a hard run. Water pressure at idle is a couple pounds and between 10 cruising and 15 WFO (measured at the top of the intake) also oil temp is good too. The t stat had the relief hole when installed but don't think it would bypass enough water to keep the motor that cold. Verified temps on the block and heads with a gun and the gauge is accurate also lake temp was in the low 60's. My thought at this point is maybe the stat is opening early and plan on testing in a pan on the stove today. Anyone have any other ideas other than a bad thermostat?

Well it wasn't the thermostat tested on stove worked as designed. Maybe it just bypasses enough water with cold lake temps to not get block over a 100 degrees. I'm not sure there something is wrong other than I wasted $300 on something that doesn't work any better than what I had.

I'd be interested to find out what you learn. I have a 510 BBC with a cross over, no thermostat and no bypass. I can't even get to 100 degrees on the lake. I was looking to upgrade to the same Hardin marine crossover with 142 stat and bypass so that I could run at better water temps and help get the oil temp up faster. Especially in winter with 50 degree lake water.

Pete

Mine does the same thing , tstat..... no tstat .......drilled doesn't change . I have thought about running thru the exhaust first then out to block then risers but worried in the hottest part of summer it would be a problem