I'm in the process of going through one of my HP500 carb motors. It appears that the previous shop left some trash in the block that worked it way to a couple rod bearings! #$%$#*&^%#!!!

Any way I now have a very reputable motor builder doing the work and he asked why run the motor with a 140 degree thermostat? He was concerned about burning off the condensation in the motor if it runs so cool.

Jeff

Jeff,
I'm not usre what the T-stat temp range is suppose to be in a stock Hp 500, BUT I changed my water pump impeller this year and my 1999 HP 500 and it idles @ 125 Deg. and ~150 after WOT. On average it runs about 140 Deg.
MD

Got me, mine runs damn cool too. 500EFI. T-stat is a 160.

Jeff,

Mine run around 140 - 150 as well.

Its a boat, so its cause we can. Less temp more power less knock. Is this reputable engine builder experienced in boat motors?

Jeff,
mine run between 150*-160*

The 96' and newer 500's have
oil cooler thermostats,
the oil cooler is bypassed til
oil temp reaches 210*.


jt.

I tried differnt T-stats on the dyno with my 500efi, ran best at 140*

The condensation thing has a LITTLE something to do with water temp. and a LOT with oil temp. The cooler you can run the water and keep the oil at 220*F. the better. I had to go to the 160* water thermostat to maintain the 200*+ oil temp. --- Jer