New Boat trying to start off right. 489 stroker oil recommendation's.

[hillsideshortleg]

New boat (92 400ec), found out the motors in it have around 350 hours. We dont run them hard and mostly cruise at around 1000 rpm. What type of oil would I want to use in these. I typically change oil once a year and plan on doing the transmission on the same schedule once I learn how to do it. We cleaned the spark arresters last fall and they were pretty cruddy so I wonder how well the boat was actually maintained. Is there any other yearly maintenance that should be done on the Motors? Oh, Also what should the water pump maintenance schedule be on? Oh also what about the generator oil type?
Thanks in advance

 

[PlayDate]

New boat (92 400ec), found out the motors in it have around 350 hours. We dont run them hard and mostly cruise at around 1000 rpm. What type of oil would I want to use in these. I typically change oil once a year and plan on doing the transmission on the same schedule once I learn how to do it. We cleaned the spark arresters last fall and they were pretty cruddy so I wonder how well the boat was actually maintained. Is there any other yearly maintenance that should be done on the Motors? Oh, Also what should the water pump maintenance schedule be on? Oh also what about the generator oil type?
Thanks in advance

So are these 489 stroker crate motors with 550 hp each? That is a serious upgrade to the 310 hp engines that boat came with. As to what oil......that probably is best answered by who built the engines if they came from a manufacturer. If it was a home built stroker kit......then I would believe Mobile One 15-50w or something close to that would be fine.

The bigger issue is the transmissions are not rated for 500+ foot lbs of torque same goes for the shafts. Putting around at 1,000 rpm won't stress anything.

If the flame arrestors were cruddy, I probably would change the plugs and do a compression test just to have a baseline on the engines.

I need pictures of these monsters.

 

[hillsideshortleg]

I was told a few years ago that there was something special about the motors. That was back when it first caught my eye. LOL Didnt have the money then. We finally bought the boat and saw an Motor rebuilding company name on each motor. So I called them and they knew the boat. I guess the guy who originally bought the boat new, wanted more power. The guy at the engine shop said they were 489 strokers and went into detail about everything that was done to the motors. The boat now has around 600 hours. I was pleasantly surprised at what my digging found. I didnt want to be bugging the engine shop but if it would be best to find the oil he recommends, I will bug him. LOL To me the motors doesn't look like anything special besides aluminum intakes and large Holly double pumpers and remote oil filters which I am really liking LOL

 

[techmitch]

I was told a few years ago that there was something special about the motors. That was back when it first caught my eye. LOL Didnt have the money then. We finally bought the boat and saw an Motor rebuilding company name on each motor. So I called them and they knew the boat. I guess the guy who originally bought the boat new, wanted more power. The guy at the engine shop said they were 489 strokers and went into detail about everything that was done to the motors. The boat now has around 600 hours. I was pleasantly surprised at what my digging found. I didnt want to be bugging the engine shop but if it would be best to find the oil he recommends, I will bug him. LOL To me the motors doesn't look like anything special besides aluminum intakes and large Holly double pumpers and remote oil filters which I am really liking LOL

Yea, we're gonna need pics on this one. Lots of them.
Thanks

 

[ttmott]

Here is the deal with big stroke engines - the piston skirt loads due to the connecting rod angles against the cylinder walls are much higher causing accelerated piston and cylinder wear.
To help reduce the wear a quality synthetic oil should be used. I'd stay away from the ultra-light weight oils (0W-30, or 5W-30). The engine needs that oil film on the cylinder walls.
Bearing and valve train lubrication won't be an issue.

If the engine builder put the engines on a dynamometer there should be a HP/Torque data sheet. If as stated earlier there are limitations of the drivetrain just keep the engines within that limitation. A good rule of thumb is if you are pushing the boat faster than it would go in OEM configuration then there are higher loads on the drive train. Also, be reasonable with acceleration out of the hole if the engine torque is greater than what the gear can handle.

 

[hillsideshortleg]

Thanks for the info. I was told by the P.O. that rocker arm studs had broken 2 different times. When I was talking to the engine builder I think I mentioned this and he said something about the load on them. Is this a common problem? Also is there something that pictures would show on the motors that would look different on the outside than a regular 454?
Thanks again

 

[ttmott]

Well I'm confused a bit - I thought those were stroked small block GM's. I got that from the "350" in your data.
If they are only 489 based on a big block GM then piston skirt loads are not an issue.
If a big block that is a 1/4" stroke crankshaft and 0.030 over bore.
Still, a quality synthetic oil is what I'd use.

Ok, if rocker arm studs are shearing off then the incorrect valve springs are installed and coil bind is happening or the rocker arm slots are not allowing enough rocker movement. I doubt there is a very high lift camshaft in that boat.

 

[Nater Potater]

New boat (92 400ec), found out the motors in it have around 350 hours. We dont run them hard and mostly cruise at around 1000 rpm. What type of oil would I want to use in these. I typically change oil once a year and plan on doing the transmission on the same schedule once I learn how to do it. We cleaned the spark arresters last fall and they were pretty cruddy so I wonder how well the boat was actually maintained. Is there any other yearly maintenance that should be done on the Motors? Oh, Also what should the water pump maintenance schedule be on? Oh also what about the generator oil type?
Thanks in advance

Hey neighbor! We're stuck in the Boise valley, but vacation near Bayview. I'll PM you when we're heading up again. Maybe we can meet in Sandpoint for dinner at the Hydra steak house.

 

[hillsideshortleg]

Well I'm confused a bit - I thought those were stroked small block GM's. I got that from the "350" in your data.
If they are only 489 based on a big block GM then piston skirt loads are not an issue.
If a big block that is a 1/4" stroke crankshaft and 0.030 over bore.
Still, a quality synthetic oil is what I'd use.

Ok, if rocker arm studs are shearing off then the incorrect valve springs are installed and coil bind is happening or the rocker arm slots are not allowing enough rocker movement. I doubt there is a very high lift camshaft in that boat.

We have two boats now. We hope to sell the 280 this summer. All my questions have been on the 400 with the big blocks in it.

 

[hillsideshortleg]

Hey neighbor! We're stuck in the Boise valley, but vacation near Bayview. I'll PM you when we're heading up again. Maybe we can meet in Sandpoint for dinner at the Hydra steak house.

Stop by and say hi. We are not much for dinners but please stop and say hi. we are at The Hope marina.

 

[Scott06]

Thanks for the info. I was told by the P.O. that rocker arm studs had broken 2 different times. When I was talking to the engine builder I think I mentioned this and he said something about the load on them. Is this a common problem? Also is there something that pictures would show on the motors that would look different on the outside than a regular 454?
Thanks again

If the studs are breaking then something is wrong with the valve train geometry or parts mismatch. things I would look for is rocker to retainer contact and retainer to valve seal clearance, or coil bind.

as you move up into higher performance cam with higher lift and duration You need higher spring pressure and custom machining to the spring pocket and valve guide where the seal sits. All this is harder on the valve train. If the studs are not strong enough for spring pressure or you have parts interference things break.

for example I have a 65 GTO that I did a stock overhaul of in the early 90’s . Have a stock type valve on done where the machinist cut the valve guide tops down for Teflon valve seals. For some reason he left the exhaust guides .090” higher than the intakes so the exhaust retainers were kissing the tops of the seals with a stock lift .407” cam. Fast forward 30 years i put a mild cam init with .466 lift which on paper shoudl work with stock valve train… Luckily I checked the retainer to seal clearance. I needed to use comp cams retainers that were .050” higher in terms of retainer to seal clearance. Because that was higher some of the springs were too tall in installed height necessitating shimming for correct installed height.

first I would talk to the builder as some thing is wrong,may not be what the builder did, maybe something PO did.

in absence of any other recommendation I would also recommend Mobil 1 15W-50. Seems to work best at higher rpm in my stock 5.0. The merc 25-40 oils seemed to either foam up or loose viscosity after good hard higher rpm use, and oil pressure would start to drop.

 

[PlayDate]

Who did the engine work? That is a unusual response from an engine builder on breaking rocker studs. It does sound like somebody made a mistake on the head assemblies....hopefully they looked at the other stud assemblies.

I'm curious how these engines push the boat. Do you know what size props he ended up with and what performance improvement he got with almost doubling the horsepower?

The Cruise on the gas engines for your boat was 18 knots or about 20 mph.

 

[Creekwood]

I would have thought you would want to stretch the legs on those big blocks periodically to ensure the cylinders don’t wear below TDC creating a pinch point when you do open them up. Running all the time just above idle isn’t great for a motor. I’d love those in my 330. With the right props it would be a rocket.

 

[ttmott]

Who did the engine work? That is a unusual response from an engine builder on breaking rocker studs. It does sound like somebody made a mistake on the head assemblies....hopefully they looked at the other stud assemblies.

I'm curious how these engines push the boat. Do you know what size props he ended up with and what performance improvement he got with almost doubling the horsepower?

The Cruise on the gas engines for your boat was 18 knots or about 20 mph.

I was wondering how the horsepower doubled with such a modest increase in displacement.

 

[Espos4]

Be weary of high lift long duration cams which may have increased overlap as well.

This may work well on the street but causes issues on a marine engine, exhaust reversion will draw water into the cylinders.

 

[PlayDate]

I was wondering how the horsepower doubled with such a modest increase in displacement.

I was too........I believe they also increased compression. Just a quick look at 496 stroker motors at Blueprint Engines:

GM BB Compatible 496 c.i. Engine - 600 HP - Deluxe Dressed with Black Pulley Kit - Carbureted

BluePrint Engines 496 c.i. big block GM style stroker cruiser crate engine - dressed longblock with carburetor. Black Complete Front Accessory Drive System. Includes 30 month / 50,000 warranty & BPE Dyno Promise. Part #: BP4967CTCKB

blueprintengines.com

• HP & Torque: 600 HP / 568 FT LBS
• Compression Ratio: 10.1 to 1
• Aluminum Heads
• Hydraulic Roller Cam
• Forged Crank
• Hypereutectic Pistons

The factory rating for the 1993 7.4 Mercruisers was 340 HP but that was adjusted to 310 HP in 1994 based on how HP measurements were done at the time. Same engine.

The 496 Strokers can go to 600 HP but that is with a lot of work. I took a guess that his were around 500 HP and that the base engines were 310 HP.....not double but a 200HP increase should be a noticeable improvement. The torque is really high. The stock engine puts out 330 ft lbs of torque. The BluePrintEngine has 586 ft lbs which is about 120 ft lbs higher than the ZF transmission is rated for.

Just curiosity on my part.....I'm sure there is a formula someplace that can estimate the performance improvement given the weight, hull design and the efficiencies of the boat.

Cruise speed with gas was 18 knots and with diesels was 20 knots. 250 ft lbs of additional torque would improve that I would speculate to the 25 knots on gas depending how it was propped. Of course the gas bill would also be higher.

It would be interesting to know the real world numbers on these engines in that 400 EC.