SDPC Tech Tips: Marine Engines

In today's tech tips, Nick goes over some common questions we get regarding street car crate engines and marine use. There are distinct differences that could end with you weighing anchor with that low run-time crate engine and...a voided warranty!

Although we are happy to sell you a crate engine, we caution customers against this route and recommend using the proper tools for the job at hand.

#SDPC #SDPCRaceshop #TechsualHealing #Marine #JustBoatStuff #TechsualHealing

[rvdogfl]

I guess I screw up and put a L31 crate motor in my boat with fresh water cooling 10 years ago. when is this thing going to blow up? It has been running strong for 10 years.

[anthonystephens]

I am in the process of buying my first boat!!! I have been doing my research in various areas!!! THANK YOU FOR BEING SOOO DAMN SMALL!!! I LOVE THE WAY YOU EDUCATE YOUR VEIWERS!!! I'm a new fan!!! 🙂

[robertbailey]

You are assuming that all marine engines are raw water-cooled. Basically every boat that is in saltwater is not. They use the same coolant trucks do and run at almost the same temperatures.

[moccasinmarine]

Some of the points are valid, some BS. Mercruiser doesn’t add extra clearance to marine engines, same as car truck engines. The computer will run a truck engine same as a marine engine, cam isn’t radical enough to need recalibrating. Some of this is just marketing bs so you pay a higher price.

[THESLlCK]

FACT: If an engine runs, you can put it in a boat

FACT 2: If an engine does not run, you cannot put it in a boat

FACT 3: I need an engine lol

[Hillsidecreeping]

I have a 400 small block carbureted it was a short block build for a truck used the same cam crank etc swapped marine applications on it from heads up and 4 years later still runs great I would say it loads up with fuel after coming in hot but lil nuts rev and clears up I’m just saying diy it can work vortex is different but old school carb motors easy

[alaskalife]

Someone help this guy because he is having trouble breathing. He is constantly gasping for air!

[mikeallmon]

they are the same as the GM crate engines. The local dealers buy them from GM and not Mercruiser or Volvo. Stainless steel water pump impeller? all the same. My machine shop says no difference lift on "marine cam". I'm going on inland freshwater boats. All of the head gaskets I use have stainless steel openings in the head gaskets anyway.

[SportModDriver]

Ring gap has a little more gap for expansion due to thermodynamics, MLS head gaskets, brass freeze plugs, severe duty stainless steel or inconel exhaust valves, valve springs are whatever the cam needs or requires, the cams typically have less duration (about 224 degrees max at 0.050) and a higher LSA (112 to 114) to avoid reversion (unless you have exhaust above the water line then it doesn't matter)....I personally also run my mains just a few thousands looser for thermal expansion. I would say most boat engines have hypereutectic pistons but forged is always better for strength. Also, boat engines aren't about horsepower, it's about torque! Most boat engines rev less than 5500 rpms. You want power in the low to midrange band. The more torque, the more pitch on your prop, the more speed at a lower rpm and faster times to plane. That's why you see tons of big blocks in the 20' and larger boats. Fresh water cooling is a plus if you have it. There's no crazy science to it besides protection from corrosion, heat and reversion. However, you could just run a regular car engine but longevity might be sacrificed. But I have seen people pull a 350 out of a car and run years on it. I would not recommend it though. However you still need to use the coast guard approved carburetion, charging and starting systems with flame arrestors. Noone wants to go boom!

[WRMD]

I remember back in the 80's you couldn't get a stock small block v8 engine over 200 hp! (unless you bought a Corvett) I remember the 225 hp 305 Chevy in our 1978 Bayliner. That engine would SCREAM! At the same time I was in high school shop class working on a 350 in a Caprice, and honestly my grandfathers fuel injected 3.8 Buick would blow the 350 away! They went for years making v6's that would (easily) outrun most v8's until about 1996 or so. I also remember riding in a police crown vic verses the civilian model. WOW! NOT EVEN THE SAME CAR. Fact: If it says marine or police on it, It has power!

[BackyardBeeKeepingNuevo]

My Sea Ray will run 3, 000 rpm for 3 hours at a time running up Lake Powell from Wahweap to Bullfrog. (The lake is 186 miles long). You are correct on the valves and the bore and everything else you mentioned. If you run street heads and are carb’d and run too lean you’ll drop a valve seat especially in older engines designed for leaded gas. I know. I’ve done it. Bottom line in marine engines even mild performance ones its a pay now or rebuild it later and pay a lot more type of deal.

[bigredracer]

10👍's up SDPC thanks again for taking us all along with you

[hildablanco]

Poker run engines are very special they manufacture there Owen piston rings connecting rods and oil pumps and use special fuels

[danmatte]

Thank you for clearing up the confusion.

[kennethhacker]

Great presentation..alot of mercruiser engines don't have heat exchangers for engine cooling..I remember a guy down at the marina put aluminum heads and intake on his non heat exchanger engine, it was only a week and that engine was toast...

[HoldFast-unfc]

Good video. Also marine engine run cool water constantly from where your boating instead of a hot radiator. Maybe the next truck I get I will put a marine engine in the truck.

[stevenwatts]

makes you wonder if marine engines might be a decent choice for a racecar as well. thats why we use truck engines because they are a little stronger, so if marine engines take truck engines and go a step further strengthening them then i might just have to build/buy 2, one for the boat build and one for the drag car build. lol

[craigmonteforte]

Thankyou for this video you are one of the few people that got this correct i beleive the confusion in general is from years ago in the 1960s and 70s more Specically GMBlocks there weren’t too many differences in the Marine Engines yes the Bronze Freeze Plugs, a different Cam and they used a Forged Crank to handle the Tourque often in those days the GMMotors used in Trucks, Industrial and FarmEquipment also utilized Forged Cranks i think the SmallBlock 283 motors came with Forged cranks in some of the Muscle Cars and Trucks i’m not a GMexpert but i recall Oldtimers saying it was the Corvette Impala and some Trucks that had those Forged Cranks, my Da remembers that a lot of HotRodders would buy up any old Chris Craft Engine they could and use that to build a high Performance motor Chris Craft used GeneralMotor and Ford SmallBlock and Big Block engines in the majority of their Motor Yachts so there were plenty of them out there FYI i lived inFlorida off and on for many years

[wizzylizzy]

All alloy ls and yojr worried about corrosion? Mate it’s alloy. And all the gaskets are stainless now. Everything is built to spec these days. Maybe a 1975 350, this is 2023 now

[timcarroll]

Boat runs at 175 degrees. There is not a bit of difference between a vortec 350 short block and a gm truck 350 short block. Bore pistons crank rods are all exactly the same. I just rebuilt two Merc Mag Mpi's using salvaged truck vortec short blocks. They were EXACTLY the same. They just slap marine on it, put brass freeze plugs in and charge you an extra grand.