Formula311-SR1

Looking for a high flow 140 thermostat. CP has them, but I wouldn't have it by the weekend.
The Hardin version seems to hang down pretty far into the intake, does this cause any issues?
Does it matter if it's for an aluminum victor JR intake, with a crossover?

thanks

ghittner

No matter, I'm running a Sierra 142 Degree Thermostat on a 900 HP motor, It's fine.

Formula311-SR1

Is the sierra version the thin version?
I have the same one with 2 - 1/8 holes drilled and I'm having problems with what seems to be air pockets.
With the thermostat in, temp heads up to 190degrees. With the same thermostat with all the guts cut out I can't get over 120. I have tried two, first one would bounce between 140 and 180. Very inconsistant temps
Was hoping the high flow might work better.

ghittner

I have the upper one. Blower and crossover. The thermostat I was having trouble with was a brand new factory Merc one out of a Merc box. It was brand new and was identical to the old one as the old one had no holes in it either. My temp would would rise and fall between 160 and 200 all within 15 or so seconds without the holes. I drilled the THREE holes into ANOTHER NEW SIERRA thermostat from West Marine and all is fine now. Anyhoooo, new Sierra thermostat, drilled the three holes, problem solved.....Chuck the one you have, buy a new one, drill the THREE holes Go a little bigger than the 1/8, like two sizes (I did upon Stainless Marine's recommendation) and try it. It worked for me last week!

Formula311-SR1

The three holes you speak of, they are just in the flat area around the thermostat?
I'll grab a new one at west marine and go with 3 holes. The one I have been using is the merc replacement

Thanks

ghittner

Three holes in a triangular pattern in the hat. ( The flat area around the outside) Slightly bigger than 1/8 Please post your results.

Formula311-SR1

first shot out, temps went right up to 190-200. 3 holes 1/8"
Put in one with 4 holes around a 1/4 that I had. Temps went down to 130. Ran for the rest of the day between 110 and 130. Plan is to enlarge the 3 holes and try that setup again, checked in water on the stove and both stats open at the same temp.

PatriYacht

Are you sure the rest of your cooling system is working correctly. I've never had my temp vary more than 10 degrees when everything was working right. A little bit of seeweed in the wrong place can really ruin your day. Btw, I use 120 degree therms from ASM in my 540's with the three 1/8 holes and a crossover. Temps don't vary more than 5 degrees after warmup.

baja bailey

This sounds similiar to a problem I am having. Had new raw water pump put on as well as new thermostat as well as backflushed due to sucking up sand. Ever since my temp will only stay steady on 170 like it always has untill I run above 3500 rpm, then it will climb to 200 in a hurry??? If I cruise at 3000 or less it stays on 170...

ghittner

You're on the right track, don't deviate you are almost there!