Did the marina wreck my engine?

[Cadence]

Originally Posted by Cheechako

Yeah, truck engine has a different cam for more torque on the low end is what I heard. Not sure if the 5.0 is 4 bolt? I think the 350 /5.7 is... When I was looking for a 5.0, the 5.7 was actually cheaper yet because they are so prevalent out there. I guess they are interchangeable...

You may be right on the cam? The 5 and 5.7 are essentially the same block.

I wish my little 21 fter had a 5.7 not the 5. Although the five towed a 48 fter 30 miles fine. I changed props from 21" pitch to 17" for that. I never change it back. Jumped out of the hole about the same. A good fishing and diving toy.

[a64pilot]

You know the funny thing is, it cost about 3 or 4 times as much to re-power a little Baby Diesel?

[Cadence]

Originally Posted by a64pilot

You know the funny thing is, it cost about 3 or 4 times as much to re-power a little Baby Diesel?

I would rather have a diesel just not on a semi go fast boat. Today a go fast has 2 or three monsters hanging of the stern. I guess it is good if you can afford sport fishing tournaments or can carry enough kilos or be a tow boat.

7 knots is fine with me.

[Compass790]

Originally Posted by a64pilot

You know the funny thing is, it cost about 3 or 4 times as much to re-power a little Baby Diesel?

Only if the little baby diesel has marine attached to its name

[Joe from ny]

How about "Michigan motorz"? Are their mercruiser rebuilds quality products?


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[Cheechako]

Originally Posted by a64pilot

You know the funny thing is, it cost about 3 or 4 times as much to re-power a little Baby Diesel?

Yeah, it is hard to figure. It's production numbers I guess. So many of those GM blocks were made they're a dime a dozen. The other thing is they wear out so fast in marine applications. You would think running on hard ground would be harder than a prop in water but it's not. Getting out of the hole on a planing powerboat is hard on engines. You can have a fairly low hours engine with a lot of blow by. Hard on bearing and rings. At least from what I've seen.

[Dymaxion]

2nd opinion asap. I've had a main bearing go out in a few minutes in an engine woken up for the spring. Old engine and the oil pressure didn't build, so the bearings scuffed then started hammering. If equipped with an oil pressure gauge, see what it says at idle and at around 2000 time, no load. An old rag left in the sump isn't impossible. No oil in the sump isn't either. Had one place finger tighten the drain plug, it unscrewed itself after a little while.

[Joe from ny]

Anyone have experience with Michigan Motorz?


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[LakeSuperior]

Originally Posted by Joe from ny

Anyone have experience with Michigan Motorz?


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Bought a 454 marine long block (std rotation) from them last summer for my 35' 1978 Bertram. The block arrived in a nice covered crate and was well wrapped in a plastic sheet.

I have about 30 hours on the block. They were good to deal with and turned some remote oil filter parts around very quickly as the original parts did not fit the new block. All-in-all a good experience.

I went with them because they came recommended by several different folks.

[Joe from ny]

The boat yard tells me that 620 hours is normal for a motor to go bad. most other yards tell me that is way too soon. Motor is a 5.0 Mercruiser, carbed. 20 years old, but the part that went bad does not see water. piston rod lower crank bearing. is those hours reasonable time for the motor to take a crap?

[a64pilot]

Issue with Marine gas engines is the RPM and load they are run at, in an automobile you rarely see sustained RPM above 2,000, you may see much higher during acceleration for a few seconds, but sustained cruising, usually about 2,000 or so.
Same motor in a boat, will be run 4,000 RPM or higher, continuously.
Math guys help me out, but you double the RPM, you square the inertia? And if so wear rate follows right along with inertia.

600 hours is premature, I'd guess sometime in the past there had been some damage from not changing oil, run low on oil or something.

[Cadence]

Originally Posted by Joe from ny

The boat yard tells me that 620 hours is normal for a motor to go bad. most other yards tell me that is way too soon. Motor is a 5.0 Mercruiser, carbed. 20 years old, but the part that went bad does not see water. piston rod lower crank bearing. is those hours reasonable time for the motor to take a crap?

I had a 5.0 four bolt main Chevy block and a Cobra outdrive. 620 hrs. sounds like a reasonable no. of hrs. for yours to die.

[Joe from ny]

looking over the estimate that they gave me to put a reman engine in the boat shows they estimate 15 hours to move all the engine accessories (pulleys, fuel pump, etc...) from my motor over to the long block. is that about fair? or is that estimate excessive?

[amytom]

Originally Posted by Joe from ny

looking over the estimate that they gave me to put a reman engine in the boat shows they estimate 15 hours to move all the engine accessories (pulleys, fuel pump, etc...) from my motor over to the long block. is that about fair? or is that estimate excessive?

Did they miss a decimal point? 1.5hours?


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