FWC Thermostat Difference???

So my '87 PCM 351 is FWC, and I was looking at getting it to run a little cooler. It runs at 180 right now. I thought a cooler t-stat would be a good idea, but after doing a small amount of research there seems to be a difference between the RWC and FWC t-stats. The one SKIDIM sells for my application is a 170. Because I am FWC do I need to be running a higher temp?

not sure what you two clowns are talking about RWC (Raw Water Cooled) vs. FWC (Fresh Water Cooling) there the same damn thing and use the same t-stat.

Now if you are refering to a closed cooling system on a marine engine that uses anti-freeze vs. RWC/FWC water from the lake then yes closed cooling system will run a higher temp.

nuttyskier2002 wrote: However if your engine was originally equipped with RWC system, there is a difference in piston to cylinder wall clearance in the short block (as opposed to a FWC system).

Just for converstaion purposes can it be verified that Correctcraft had two different engines sitting on the shelf depending on what cooling system was going in a boat. I understand the concept of the clearances but find it hard to believe that this was the practice.

Have to say there is no difference in the spec sheet , be it in "Slang terms" between "open loop and closed loop.
On a EFI engine the temp has to be higher for proper operation of the cold start circuit.
But with an older Carb model the temps are not that critical. A 140 will allow a little more advance to be used and sometimes a lower grade of ful before detonation.
As far a piston to cyl. clearance these are going to be the same after warm up regardless of water temp.Prove me wrong on that one.......Boat dr..
I am running a 140 at 39 degrees total advance on 89 octane.....

Allen, flat tops and the 63cc heads should give me about 9.75, at least that is what Steve says.
Can run the timing up a tad more if Premium is used but see no need for the cost/ performance diffence.......Boat dr

She do not like the Northern gas tho.Boat ran like crap on the High test stuff they have up there. But once home she is happy as a clam with "our" 89 go figure........Billy

always heard it refer to as closed cooling system not fresh water system.

boat dr wrote: Allen, flat tops and the 63cc heads should give me about 9.75, at least that is what Steve says. Can run the timing up a tad more if Premium is used but see no need for the cost/ performance diffence.......Boat dr She do not like the Northern gas tho.Boat ran like crap on the High test stuff they have up there. But once home she is happy as a clam with "our" 89 go figure........Billy

Suuure blame it on the gas!!!

Nutty, there are pro's and cons to this line of thinking.My stroker was set up with less clearance than what you would consider safe.
2.5 thousands piston to cyl.is tight in the marine standards but with proper break in it will yield a super long life.
Ring gap was aslo a little on the tight side ,002 to the in. of bore.This too can cause a "cold seize" early in break-in if proper warm up is not followed.
Mercruiser has been since the early '90s has only removed the exhaust valve guide seals as their sole means of engine work to prepare their engines for marine usage. And there are several out there that have no ill effects from the standard clearances.
Not a lot of engine builders go thru the care and time needed to "break in " an engine correctly, so these are the reasons for the excessive gaps used for "marine standards."
Kinda like "I will cover my ass thing." Build it loose and it will not seize.
This is just my opinion and it comes for free, so consider that if you want a refund..............LOL

He's an above average fella!   

I have a 150 F thermostat in mine. Its great! When i bought it, it has a 180, too hot for me!

Karen has a camping spot reserved for us at Hatty Sherwood for '09.Kinda soon to be planning ,,,,BUT............Boat dr

I've always used a 160* in mine in fresh, i.e., non-salt water. I dyno'd it and it made 37 more HP than the 143*! OK, that's two lies in one sentence. But I have always used the 160 and always heard that the engine's efficiency, which includes fuel mileage, was a little better with the higher temp, like nutty said. Also, for clarity's sake, the issue isn't that a 160-180 T-stat is a special requirement for FWC'ing, it's that the 143* IS a requirement for any RWC engine venturng into salt water, as the salt really starts to reek havoc above that temperature. Didn't this come up a few years back?

Mojo wrote: Fear not JB, there is a strong chance that the reunion will get pushed forward a week in July.

To the 4th of July weekend?

Forward as in week later.... as opposed to a week back.. Keith's anniversay always falls on the 11th weekend.. He's thinking of moving it to the 18th etc.... Another week can add some warmth and lower winds, but ya never know...

Moj'