the duke

Dry Sump is great. As was said in Cup where 10 HP can win or lose a race. For your motors (and most of the rest of our motors), its an absolute waste of your money for something that is not needed. You are talking thousands of $$$$ for the pan/pump etc.

Buy the best Moroso/Melling high volume pump and have a lot of money left over for gas.

stevesxm

disagree completely w/ duke and mobileman. motivation has nothing at all to do w/ rpm OR quality/cost of wet sump.

if you are flying along in your boat at 5000 revs and fly to 1 neg g all that oil that used to be near your oil pick up is now up in the pistons somewhere... and thats just about the time the props come out of the water and the motor free revs to the limiter before you catch it.... and for that one thousand and one count at the worst possible time, you have no oil pressure.

on the cars its for side loads. on a boat , while ive never seen a boat pull 2 g side load, im sure that the oil in the pan takes a serious forthing and beating in agrressive running.

thats when a dry sump saves you.. it doesn't save you when you are idling around the dock.

it saves you when you are out screwing around in the chop, scaring the bejesus out of the girls hoping they'll take their tops off

and later on a week or two later when it runs the bearings youll say... " geeeze... i wonder how that happened."

you configure the hardware for what you are going to do with it...

gonna idle it around and run out to the club w/ the wife at 2500 rpm ? wet sump is fine.

gonna take the same boat and beat it and run it hard and fly it and the like and expect the motor to live ? dry sump.

the oil system doesn't work if the oil isn't where the pick up is.

MOBILEMERCMAN

stevesxm, Fine theory, Just because the boats in the air doesn't mean your pulling neg G's. If you keep tripping it you will encounter neg G's but that is another thought entirely. I agree dry sump is better, but disagree with you too on the need.
Jim

2112

My wet sump pan has a "roof" over the top of the sump, baffles and doors to prevent oil from accumulating away from the pick up and a scraper to get as much oil off the rotating assembly as possible.

Is it a good as a dry sump? No. Does it allow the pick to run dry? No.

stevesxm

well.... all good and valid points. and i built all sorts of pans for race motors that attempted to emulate drysump performance for catagories where dry sump was not allowed.

and like your wet sump pan w/ the roof, they work to some degree. but my point is simply this.

you can make anything emulate anything is you are smart and clever enough. the question i always asked myself and my clients was... " how will this hardware be used ? "

and then i built it accordingly. now.... as i said earlier... if the boat is a day tripper , then a wet sump will be fine.

if the boat is going to see occasional thrashing then , yes, you can GET AWAY w/ a wet sump. i do now and so do thousands of others. but given a CHOICE, i would spend the money EVERY SINGLE TIME and dry sump any motor that was going to get subjected to hi g thrashing even occassionaly. it is give away cheap compared to the day when you need it and its not there.

on a wet sump pan with the roof , if its effective, you have drain down issues to contend w/ and the crank whips the oil.

on a wet sump there is no real way to deaireate the oil

and the notion that there is no neg g when the boat flies is nonsense ( there is 1 neg g as it goes weightless at the top and you look over and your beer that used to be in the cup holder is hovering in mid air like the oil is in the pan... and thats not opinion... thats physics) ... but thats neither here nor there...

there is no right or wrong to this discussion. it only comes down to the same decision making process that you go thru when writing the specs for the metallugy , materials and component selection of ANY motor you build. you believe what you care to believe and decide based on that perception of cost vs value.

if i have 30k in a motor with the best of components that i then plan to really use ( because , after all, thats why i SPENT all that cash) i would have to be pretty dumb to put a 25 $ oil pump and wet pan on it.

but thats just me.

BadDog

I need a wet sump for my cooler when crossing barge wakes...

I do see the point of the oil loosing contact with the pan. Thought I read about accumulators to bypass that temporary situation. It would still seem you might have an air bubble in the system and air does not support bearings very well.

fabricator

.......and if your beer spills, THAT'S considered alcohol abuse!

Seriously, your point is well made.

the duke

Stevesxm, it seems you are talking about some serious beating of the boat. like old time offshore races. One heck of a lot more than 99% of the people do. with correct work done to the motor, drainback is very controlled, and the crank is going to have wipers/windage trays etc on it. Not to mention that a good hi po oil pan has all sorts of ways to keep the oil trapped in the sump. I've run wet sump motors on circle track pulling way more than 1 g, with zero oil issues.
negative g force is accelerating down, faster than a free fall. You would have to be accelerating down at 2g's to net a minus 1g, as 1 g is normal. I guess if you launched off a 20' wave down you could do this.

I am not by any means saying that dry sump isn't a better oil system, because it is. Its just not a system that is needed by the vast majority of boaters.

stevesxm

i understand... and actually agree for the most part. i have a top gun w/ 502 mags. stock wet sump. i don't race it. but i do use it fairly hard. thats the fun of it . and when the boat is in the air, all i can think about is whats happening in those motors ( and what the cabin is going to look like later)

my best professional sense is that these motors take a lot more of a beating then you might think... but maybe not and i certainly don't have any hard data to support that conclusion. but i see it this way.... when guys are building big v8 for hot rods on the street, that environment doesn't really support the kind of abuse that you have to protect against most of the time... the boats are a different deal.

hostile environment and the opportunity to put genuine racing stresses on the hardware even if it is not intentional.

bottom line for me is that i think its a very cheap deal in a dollars per value sense. not so much that i HAD to do it when i got this boat and motors ... but enough that when they come out in a year or two, they will be so equipped when they go back in.

Iggy

If you guys are worried about loss of pressure from flying you should have an accumulator (pre-luber) that holds a couple quarts of oil. This way if pressure does drop from negative G's the reserve oil will make up the difference.