some more questions- what happens when you leg it at 4000+ for some length of time? Where do they go then?

Did you SC the engines from stock? if so you may need to add a oil cooler to each if you start getting past where you are now.

sustained 245+ starts to get bad for your engine longevity.

Dan Olson, Teague, CP, Rex, and other sell very high quality coolers.

I use an aeroquip my self. Cant get em anymore, but I wont ditch it until it doesn't work anymore which is hopefully a looong time.


Uncle Dave

The 250 B&M blowers were already on the engines. I replaced the 454 block with a Dart 502 block and had all new internal parts. I don't really run my boat over 4000rpm for a very long time... maybe 20 seconds. I have the old style 1 Inch bravo 1's and I'm afraid I am going to break them. I don't want to be out of a boat until I can afford some Arneson Surface Drives and add some more modifications to my engines to increase Horse Power. That's going to cost a lot!

The stock engine cooling stuff from merc barely gets it done at its rated power, but is way better than nothing. It sounds like with a modest amount of horsepower gain, you just need more oil cooling capacity if you're going to be expecting these units to live a long time.

Does that engine have iron heads?

I'd lower my Water T stat to no higher than 130 ,

- or maybe even 100 if you run for long periods of time the risk under 130 water is moisture not burning off quickly enough and contaminating the oil.

Arnesons are an awesome, but unconventional package, and as long as a boat closely matching your setup has been modded by them - you are golden. If not you could have problems (as you could have problems with any aftermarket drive not exactly matching what you have now)

If your parameters fit an Arneson it is a very worthy investment imho.


Uncle Dave

BTW- there is a ton of argument about whats too hot with little agreement about the upper number.

some will tell you 280 is where things go bad other will tell you the oil companies rate their stuff to 330

Oil coolers "tend" (more controversy) to measure the drop from 280+ adding more controversy. (The department of redundancy department)

- and absolutely everyone agreeing that cooler is better to the water boiling of 212.

- so head for the low target.

Uncle Dave

I would look into a larger oil cooler with a thermostat inline. This system will will keep your oil at optimum temp. LIke stated before the merc. system in barely adequate at best. Adding the superchargers probably put you over the edge in the oil cooler department.

So what's too cold? My temp (taken from sender installed just in front of pad adapter) is 160-180. It has stock thermostat in adapter, I think 165*, but Merc could not confirm this.
Water never over 110, no thermostat per Whipple direction.

IMO, 220-230 is damn near perfect for the oil temp. I mean....don't you want it to be more that 212 so condensation/dilution gets burned out of the oil??

My boat runs at 130 water temp and 230 oil temp.

Just talked to Teague, they say I'm right on the money & they run their Whipple motors without any thermostat & like to keep the oil cool. Lot's of conflicting opinions, probably none are wrong, just different. They say run it, a bit of condensation is normal & they see it in their motors too. I'm not talking thick goo, just a little white. Maybe if everyone looked after a hard run they'd see it as well. Anyway, still waiting for a call back from Dustin for a second opinion, he'd be the one who has seen more blower motors than Teague.

FWIW, water vapor starts to develop around 160. Regardless of the temp over that, there's no magic about getting that water vapor out of the system. Some of it gets sucked out through breathers, some of it is going to condensate under the valve covers. And since it's not a sealed system, as soon as it cools, moisture will find its way back in.

Conventional oils break down in the low-mid 200s, synthetics stay together into the 300s. And then they're burnt.