Can you help me reconcile this statement,

"Automotive engines are made for stop and go. Not continuous power like a aircraft or boat. It will be interesting to see how it holds up with continued load."

1.) With every vehicle I see on the interstate?
2.) Can you further help me reconcile that statement with the Chevy 350 in my Master-craft?

Thanks
--Chris

My biggest fears for him "first flight" are a runaway over-rotation and/or uncontrollable wing flexing....

Even an innocuous-seeming high speed taxi and the effort of "just trying to get the weight off the nose wheel" could turn very ugly very quickly

Can you help me reconcile this statement,

"Automotive engines are made for stop and go. Not continuous power like a aircraft or boat. It will be interesting to see how it holds up with continued load."

1.) With every vehicle I see on the interstate?
2.) Can you further help me reconcile that statement with the Chevy 350 in my Master-craft?

Thanks
--Chris

Can you help me reconcile this statement,

"Automotive engines are made for stop and go. Not continuous power like a aircraft or boat. It will be interesting to see how it holds up with continued load."

1.) With every vehicle I see on the interstate?
2.) Can you further help me reconcile that statement with the Chevy 350 in my Master-craft?

Thanks
--Chris

Beg to differ, other than the cam and distributor there are no significant differences between a 350 chevy 4 bolt main auto engine and the 350 marine engine. And perhaps as a negative, my tournament ski boat only held 4 qts of oil.

And it operated many, many trouble free hours running at 75%+ power.

What i do not know about engine would fill volumes. But i do know they crank out 750 hp atLeMans for 24 hrs from light weight small block motors under grueling conditios,

Sorry Rick you are wrong. Your engine in your boat has different bearing clearance and different valve setup, most have different cam to protect against reversion. Plus it’s got unlimited cold water to cool
It. Lots of guys that thought the same thing as you and bought crate motors for boats and blew them up.


Sorry I even made the comment about boat motors. Trust me I know a thing or two about boats, more than I wished I knew.

Fact still stands that if aircraft and auto engines were interchangeable we would be in a much better place in GA than we are.

Mike

I dunno about only 20hp.

80+mph for hours at a time (pretty common for a family sedan with a four cylinder or a small six), getting 20-25mpg, that's 3-4gph and a lot more than 20hp.

Chris I mean to say auto engines are not made for high load continuous power. When you are on the freeway you are using very little power relative to what the max power is.

Aircraft and boats run at 75% power for long periods of time. Go run your car at 75% for 1hr straight and see how it goes. Better find a really big hill or a trailer and a hill. It’s just not how cars are ran. There is a reason a 300hp aircraft engine cost more than a 1500hp automotive engine. Its continuous power that’s the challenge.

And your Mastercraft 350 is not the same as a auto 350. Different tunes, bearings, etc.. plus your boat has unlimited water to cool it. Lots of variables but you can’t just take a auto engine and put it in a aircraft.

I race OffRoad trucks and we use a spec LS3. Yes it’s the same LS3 that’s in a Corvette but if we didn’t add way more cooling, race gas, and different tune it would self destruct in the first 10 miles of a race. In our truck we are at max power most of the time. The engine goes thru some great testing at GM and has proven it can go WOT for extended times but not in the corvette. They do that testing in a dyno room with unlimited cooling.

Mike

[quote="Chris Close"][quote="Chris Close"][quote="Michael Pyle"]
Can you help me reconcile this statement,

"Automotive engines are made for stop and go. Not continuous power like a aircraft or boat. It will be interesting to see how it holds up with continued load."

1.) With every vehicle I see on the interstate?
2.) Can you further help me reconcile that statement with the Chevy 350 in my Master-craft?

Thanks
--Chris[/quote]


Chris I mean to say auto engines are not made for high load continuous power. When you are on the freeway you are using very little power relative to what the max power is.

Aircraft and boats run at 75% power for long periods of time. Go run your car at 75% for 1hr straight and see how it goes. Better find a really big hill or a trailer and a hill. It’s just not how cars are ran. There is a reason a 300hp aircraft engine cost more than a 1500hp automotive engine. Its continuous power that’s the challenge.

And your Mastercraft 350 is not the same as a auto 350. Different tunes, bearings, etc.. plus your boat has unlimited water to cool it. Lots of variables but you can’t just take a auto engine and put it in a aircraft.

I race OffRoad trucks and we use a spec LS3. Yes it’s the same LS3 that’s in a Corvette but if we didn’t add way more cooling, race gas, and different tune it would self destruct in the first 10 miles of a race. In our truck we are at max power most of the time. The engine goes thru some great testing at GM and has proven it can go WOT for extended times but not in the corvette. They do that testing in a dyno room with unlimited cooling.

Mike[/quote]

Fair points. Let's dig in.

Are you saying that a 75% load means high rpm's and the damage/lack of reliability comes from said RPM's? (Loaded question?) :-)[/quote]

In general it’s not RPM that’s the issue, at least as long as you are under manufacturer recommended redline. It’s heat. Yes sometimes RPM can cause heat but you can load a engine at low RPM and overheat it. In fact in many ways RPM can keep
Engines running cooler. More air and more coolant flow.

Point is there are many competitive variables. No free lunch.

Mike

During development of the C5, the LS1 was run at full throttle for 520 hours straight on an engine dyno (under load) and was fine at the end of the test. I've never seen a N/A LS with cooling issues, and "race gas and a tune" wont make a difference on an otherwise stock LS. Methanol would help tremendously with cooling, but it doesn't make sense in an endurance application because of consumption.

Not sure why I keep playing this game.

The LS3 actually ran many more hours than the LS1 at GM under WOT full power and did fine. But the dyno had large cool water supply. Not the same in a car.

Race gas reduces detonation which happens sooner at high temps. Tune is a general statement and can in fact protect a motor. I can “tune” a engine to reduce power at high heat loads. I can tune it to be much more safe than stock. Being more aggressive in timing reduction at knock will make sure it will not detonate. Increasing Fuel to reduce AFR will make it safer. Detonation happens more at peak power 14:1. Running 11.5:1 will make it last longer. Also reducing fuel flow, throttle body position, and timing I can make a engine safe against anything. It just won’t make full power. I can tune it so it makes 20% power to save its self against your 100% pedal position when it’s ready to blow.

Forcing a engine to make 100% of its possible power for long periods of time with limited cooling will blow it up. I know for a fact as I have done it. We tune our our race motors and have learned a lot the hard way.

My point is I think Peter should start with a conservative tune. That’s all I am saying.

Mike

any info on the belt drive setup?

Auto PSRU's Philosophy
https://www.autopsrus.com/philosophy

During development of the C5, the LS1 was run at full throttle for 520 hours straight on an engine dyno (under load) and was fine at the end of the test. I've never seen a N/A LS with cooling issues, and "race gas and a tune" wont make a difference on an otherwise stock LS. Methanol would help tremendously with cooling, but it doesn't make sense in an endurance application because of consumption.[/quote]

Thanks for posting. That is exactly right. The other thing he will not acknowledge is this is a turbo charged diesel with a re-drive. The Torque curve will allow this thing to cruise at a lower RPM/higher pitched prop/lower fuel burn (and higher altitude) than existing Lycoming's etc. Which is why it was specifically chosen.

He is dead wrong about marinized auto engines as well but that is another story. (The ONLY differences in the block/head combo is a (factory) high lift/short duration cams setup and matched head with hardened valve exhaust seals, hardened valves, and brass freeze plugs. (i.e. OEM part numbers on all of those except the brass freeze plugs) (i.e RV or heavy duty gasoline truck.) They are literally the same OEM (Ford/Chevy whether Indmar/PCM/Mercruiser) cast numbers. You can buy crated replacements/rebuilds (short or long blocks) with standard OEM stock numbers if you are willing to change out the freeze plugs yourself.

Chris

So the bearing clearance is the same on a auto engine and marine engine? You are saying the Long block is identical for a GM 454 and Merc 454? All you have to do is change the freeze plugs? Is this what your saying?

You should tell all the boat manufacturers that they have been getting ripped off all these years. Why don’t they just buy GM crate motors and change the freeze plugs?

Mike