60 vs 81

"I am deciding how to power a

"I am deciding how to power a new 29 tiara coronet. I like the newer technology of the 6.0 but the high R.P.M. concerns me. The boat runs 30 M.P.H. at 4000 R.P.M. with 6.0 The 8.1 is heavier, louder and doesn't get as good as milage but runs 3000 R.P.M. at 30 M.P.H. Any advise?"

"You will save money across th

"You will save money across the board with the 6.0, just for the reasons you stated. The 6.0 runs those RPMs for a reason, because it can. If you were talking about a 39 I would have other advise, but in a 29' boat, the 6.0 is more than enough.

Robbie Gordon just won a leg of the Dakar Rally in a Hummer with the same 6.0 in it. And since the marine industry has been using it for four years now, with virtually no failures, I think it's safe to say it's a pretty damn good engine.

Good luck
Rick"

I assume the 8.1 is not fuel i

I assume the 8.1 is not fuel injected?

Jeff

PS: NO WAY I'd own a boat that had to cruise at 4 grand! And I don't care if the motor didn't blow up for Robby Gordon.

30mph at 4000 grand says to me

30mph at 4000 grand says to me this engine is to small. I have a 30fter with a 454 that runs 30mph at 3400rpm. No replacement for displacement.

"Jeff and Bill,

The 8.1 is

"Jeff and Bill,

The 8.1 is fuel injected. Other than some economy priced "Power Pack" small block 5.0 and 5.7 engines, marketed to the repower customer, Crusader has not offered a carbeurated engine in 5 years.

And Bill, your 7.4 weighs more, burns more fuel (and oil), produces more emissions, requires more annual maintenance, won't last as long and has less HP than this 6.0. That doesn't make it bad, but they are the facts.

If you understood the technology in these new engines, the rpms would be of no concern to you. In fact, you should be more afraid to run your 454 at 3400 than run this 6.0 at 4000.

The new engines incorporate far superior components than were available when the older engines were built.

The lubrication system uses a rotary, crank mounted oil pump. It has fewer moving parts and doesn't even compare to the old system. The engine's bearings are better, the rotating parts are lighter, stronger and much better balanced. The cooling system is much better, they have roller lifters, no moving parts in the ignition system and safety devices to protect them from conditions which would destroy an old school engine.

There is a replacement for displacement, it is improved design, superior quality components and advanced technology.

Actually, there is a replacement for displacement, it's called innovation.

Sorry guys, I grew up with big block Chevys, but you have to push a 454 to it's limits to get what these new engines give you without breaking a sweat. I'm sure guys cried when they discontinued the flathead. They eventually got over it. I am putting six kids through college replacing these older engines and my business will be greatly effected when they are all gone but fortunately for me, there are enough of them out there to take me to retirement, and beyond.

Sorry, that's just the way it is."

"Rich, good buddy, I gotta dis

"Rich, good buddy, I gotta disagree BIG TIME with you here:

The technology of pistons and rings moving up and down on a cylinder wall hasn't changed much in 40 years (since Smokey Yunick--my hero!--invented moly-filled rings, proper honing techniques, honing plates and other innovations).

It's called piston speed. A longer stroke engine (which it is comapred to the old 350) turning those unGodly high rpms, has horrendously high piston speeds. That means high wear rates on rings, pistons, cylinder walls, etc. And that means oil burning will occur sooner.

On that fancy, crank-driven oil pump...This is a variation of the disastrous setup Buick first used on their aluminum V-8 of 1962. THe new design is better, but still a bad idea. (You can't find a Buick motor with this setup in the junkyard that hasn't wornout main and rod bearings.)

Instead of the pump's inlet sitting BELOW the oil level in the pan, it's about 6 inches ABOVE the oil level(and even more with a deeper installation angle). That means this new-fangled oil pump has to suck oil UP that far to just get it into the pump.

So what? Everytime the engine starts up--and instantly since it's EFI--the motor is running without oil pressure for several crucial seconds. Why? Because the oil in the pickup tube has run back down to the pan--it's empty! Ditto when, flying along, bouncing off waves (and having a great time). The oil pickup is momentarily uncovered as the motor is screaming along at 4 grand or more. Result: No oil pressure for X seconds until the pump SUCKS in more oil. Ouch! Better have lots of Lucas oil additive in there, partner.

"Well designed and reliable engines"? Sorry. The wheel has not been reinvented here.

Jeff"

"If piston speed is so critica

"If piston speed is so critical, how do you explain the outboard motor? Same piston material, same ring material, same cylinder material. 6000 RPMs all day long.

And by the way it is not the same oil pump used by Buick. The Buick pump was shaft driven. The thrust from the worm gear applied excess force on the aluminum impeller plate by the steel impeller. This caused the plate to score and loose efficiency. This new design pump rotates on the crankshaft and works like a rotary engine, there is no plate. It has one moving part. It doesn't matter how far the pump is from the oil, it matters how far the bearings are from the oil and that hasn't changed. The old type pump still has to pick up oil from the sump and deliver it to the bearings. Due to the design of the new pump, it does not drain down like the old pumps do, so oil delivery is improved versus the old type system. The millisecond it takes to refill the pick-up tube is irrelevant since the pump is still full, unlike the old pump, which drains completely down every time you shut off the engine.

I didn't say they reinvented the wheel, I'm just saying they're not making them from stone any more.

The next time I talk with the engineers at GM I'll inform them that you think they are wasting their time. LOL

Rick"

"Let's take 'em one at

"Let's take 'em one at a time:

"If piston speed is so critical, how do you explain the outboard motor? Same piston material, same ring material, same cylinder material. 6000 RPMs all day long."

Shorter stroke in most cases. We're talking under 3 inch vs. 3 3/4 on that newer "Chevy. Big difference. Also, though you're gonna argue with me, most outboards don't last nearly as long as a good inboard motor. Also, you're comparing 2 stroke vs. 4 stroke designs. The jury's still out on those high-reving Honda 4 strokes (though I've heard of enine problems with their high mileage V-Techs).

"And by the way it is not the same oil pump used by Buick. The Buick pump was shaft driven. The thrust from the worm gear applied excess force on the aluminum impeller plate by the steel impeller. This caused the plate to score and loose efficiency"

I didn't mean to imply that the old, crappy Buick oiling system was the same as the new "Chevy", but the principle of sucking oil uphill is the same. The later "Buick" V-6--called a 3800 Series engine--debuted the pump on the crank design (plus distributor-less ignition).

" It doesn't matter how far the pump is from the oil"

Want to bet!

"it matters how far the bearings are from the oil"

Ten feet away would not be a problem AFTER the system was pressured up, and that's whay=t you fail to grasp--it takes precious seconds for that new design pump to get itself going every cold start, and when the pickup gets uncovered....Ouch!

Another example: After a new GTO used for "drifting" blew a bunch of motors, so the fabricator had to go with a dry sump. (Care to guess why?) An older model SB Chevy with a baffled oil pan wouldn't have had that problem; look at the many wet sump dirt trackers out there!

Jeff"

"Allison engines use a 5.5&#34

"Allison engines use a 5.5" bore piston stroking 6" at 3400 RPMs. Then the hydraplane guys got ahold of them and cranked them even higher. So don't tell me that 3" of stroke is fine but 3.75" won't hold up.

And you're really stretching it to compare a GTO motor run sideways at WOT (which uses the old style pump) and a dry sump system.

What you fail to grasp is that this new pump will deliver OP faster than the old type pump which drains down every time you turn the engine off. The pump stays primed and full of oil. The only thing that drains down is the tube, whereas the entire pump, including the tube, drains down on the old type. The new pump also has a much greater capacity so it gets that tube filled much faster.

My new Suburban has the 5.3 engine which is the same basic engine as the 6.0. You can't crank that thing for an instant without seeing the OP gage react. I can't say that about my previous Suburban with the 5.7. After sitting on cold days the engine would actually start before the gage moved.

Jeff, arguing with you is like arguing with my wife. After 25 years of marriage I have learned "It's better to be done than to be right".

I'm done.

Rick"

"Rick I had now idea I would s

"Rick I had now idea I would spark such a debate. I truly appreciate your and Jeff's opinions. I have posed this question to a few other people, and the majority agree with you. One final comment I ordered the boat the day after reading your first reply with the 6.0. I believe it was the right choice.

Chris Hann"

Time will prove you right.

Time will prove you right.

Good luck with the new boat.

Rick