No load WOT test/block heater suggestions

[Nick]

Welcome aboard!!


I have the 671TIs and the nameplate is the same as Passages and Trojan 2650 NL, 2500 load.

I have the "Kim Start" block heaters in cooling system near the fuel pump. The heater coils are inserted in the football shaped fitting in the block near the fuel pump. The heaters are immersion type heating elements with electric thermostats. I think the heaters are 500 or 75 watt each. The thermostats are installed in the cooling system manifold. I installed the thermostats 3 years no problems with either the heating elements or the switches. The block heaters are plugged into a 110v outlet in the bilge and keep the engines at about 120F. I leave the heaters on all season at the dock, early spring through late November. Nice quick starts little smoke, dry engines.

[John Dickson]

Thanks for all the replies enginemeisters! This site is addictive, no doubt. I double checked my engines on the WOT rating. The blue OEM DD stickers say 2500 NL WOT, HOWEVER the covers have larger stickers stating 2500 wot load and 2650 WOT noload - must have been added by Johnson Towers as part of the marinization? I presume the JT conversion adds the extra 150 rpms? So is there a consensus on block heaters? Blanket or immersion?? I am in Detroit - cold springs and falls definitely. (Very cold today - 20'). My DDs are in heated storage this winter. Thanks again for all the help.

[SKYCHENEY]

Well, you can't beat the price of the pad heaters.

[Genesis]

Pads are great BUT make sure they are solidly attached AND on a flat (no imprint, etc) surface! They WILL burn up if not.

6-71s typically have a usable "football" port into which one can put immersion heaters. If you use them, either use a thermostat or use 220V heaters but wire them for 110V (this results in far less wattage, and then they can be left on safely)

6V92s and some 8Vs have that port consumed for the exhaust manifold cooling - if so your only rational choice is the pad heater option. That's what I did - one 250W one on the side of the oil pan, and another on the oil cooler housing.