Is This Engine Worth It

[Agoose]

Hi guys,
I bought a 1986 Century Meridian with a 1992 Marine Power Inc. 7.4 liter engine. The original motor in the boat was a 5.7 liter. The last owner took the alternator, power steering pump, pulleys from the 5.7 liter and installed them on the 7.4 liter. He used washers and spacers to get everything to line up. I've had two belts come off on me and one break. Now the exhaust manifold has a crack in it. The motor has 800 hours on it. 14 years in fresh water and 1 year in salt water.

I've had trouble getting the boat to plane off with 6 people on it. The boat is 28 feet long and I'm not sure of the weight of it. With 2 people it's fine. The boat draws 2.5 to 3 feet and has a beam of 8.5 feet.

My first question is should I sink money in to this motor or should I repower.

My second question is should I go back to a short block 5.7 liter.

I should mention that I have an Alpha One outdrive and they didn't put many 7.4 liter with the 7.4 because they chew them up.

Any help would be appreciated.

 

[Chris1956]

Re: Is This Engine Worth It

Agoose, A 28 footer with a single small block may not even plane out. I think you need to stick with the big block 7.4. A lower pitch prop may give you the low end power you want. Also, if you are careful to "baby" the Alpha, it should be OK with the 7.4.

You need to attend to your belt and manifold issues. I will presume the old owner bought a 7.4 long block to replace his 5.7. That may be why you have the alt andd P/S off the 5.7. You might want to check the pulley surfaces. When they get rusty, they tear up the belts. Sand 'em smooth and check the alignment of the pulleys that share belts. They do not need to be perfect, but they need to be pretty close. The exhaust manifold should have lasted longer. if the outside only is cracked, you might try to have it welded. If not, bolt on a set of mannys and check the risers for rust.

More to the point, who in their right mind would drop a single 5.7 into a 28' boat?

 

[v1_0]

Re: Is This Engine Worth It

"More to the point, who in their right mind would drop a single 5.7 into a 28' boat?"

Is "Century" the manufacturer of that boat? Sounds like someone to stay away from?

-V

 

[180shabah]

Re: Is This Engine Worth It

Sounds like someone to stay away from?

They don't exist any more.

However, they would have put more engine in there if the original owner would have been willing to pay for it.

 

[Dante04SRT]

Re: Is This Engine Worth It

Hi guys,
I bought a 1986 Century Meridian with a 1992 Marine Power Inc. 7.4 liter engine. The original motor in the boat was a 5.7 liter. The last owner took the alternator, power steering pump, pulleys from the 5.7 liter and installed them on the 7.4 liter. He used washers and spacers to get everything to line up. I've had two belts come off on me and one break. Now the exhaust manifold has a crack in it. The motor has 800 hours on it. 14 years in fresh water and 1 year in salt water.

I've had trouble getting the boat to plane off with 6 people on it. The boat is 28 feet long and I'm not sure of the weight of it. With 2 people it's fine. The boat draws 2.5 to 3 feet and has a beam of 8.5 feet.

My first question is should I sink money in to this motor or should I repower.

My second question is should I go back to a short block 5.7 liter.

I should mention that I have an Alpha One outdrive and they didn't put many 7.4 liter with the 7.4 because they chew them up.

Any help would be appreciated.

Keep the engine, get a Bravo.

 

[Agoose]

Re: Is This Engine Worth It

What kind of money am I looking at to upgrade to a Bravo?

How many years do you think I can get out of this motor?

Thanks,

Agoose

 

[f_inscreenname]

Re: Is This Engine Worth It

I paid $660.00 for this hunk of crap,

Just so i could do this to it,

[FONT=Arial,Helvetica,sans-serif]*1986, MIE/340 (7.4) 454 Big Block[/FONT]
[FONT=Arial,Helvetica,sans-serif]Dip it and hone the decks and cylinders [/FONT]
[FONT=Arial,Helvetica,sans-serif]Block was detailed with all casting debris removed[/FONT]
[FONT=Arial,Helvetica,sans-serif]Stock crank (also cleaned up)[/FONT]
[FONT=Arial,Helvetica,sans-serif]Reconditioned rods[/FONT]
[FONT=Arial,Helvetica,sans-serif]ARP Rod bolts[/FONT]
[FONT=Arial,Helvetica,sans-serif].210 Domed Speed pro pistons and pins. (They should give me 9.38 to 1 with the heads I am using now)[/FONT]
[FONT=Arial,Helvetica,sans-serif]Molly rings [/FONT]
[FONT=Arial,Helvetica,sans-serif]Federal Mogal bearings (cam, main & rod) [/FONT]
[FONT=Arial,Helvetica,sans-serif]Cloyes true double roller timing chain [/FONT]
[FONT=Arial,Helvetica,sans-serif]Seal Pro cam Chevy 396-502 cid, RPM Range 2000-4500, [/FONT]
[FONT=Arial,Helvetica,sans-serif]Adv Dur 296 intake/296 exhaust, Dur @.050 218 intake/218 exhaust, Valve Lift 519 intake/519 exhaust, Lobe C/L 110.[/FONT]
[FONT=Arial,Helvetica,sans-serif]Seal Pro lifters[/FONT]​

[FONT=Arial,Helvetica,sans-serif]Completely refreshed Chevy 14092360 heads[/FONT]
[FONT=Arial,Helvetica,sans-serif]ARP 1.90 rocker studs [/FONT]
[FONT=Arial,Helvetica,sans-serif]Seal Pro matching valve spring. [/FONT]
[FONT=Arial,Helvetica,sans-serif]S/S 1.7 roller rockers[/FONT]
[FONT=Arial,Helvetica,sans-serif][/FONT]
[FONT=Arial,Helvetica,sans-serif]Melling H/V oil pump [/FONT]
[FONT=Arial,Helvetica,sans-serif]Melling HV oil pump shaft. [/FONT]​

[FONT=Arial,Helvetica,sans-serif]Power Plus, CrossWind Series dual plane, air gap aluminum Intake Manifold from Professional Products.[/FONT]​

[FONT=Arial,Helvetica,sans-serif]Mercruiser Thunderbolt ignition[/FONT]
[FONT=Arial,Helvetica,sans-serif]Mercruiser Thunderbolt distributor[/FONT]
[FONT=Arial,Helvetica,sans-serif]Super Stock coil. [/FONT]
[FONT=Arial,Helvetica,sans-serif]8mm Accell hi performance wires[/FONT]​

[FONT=Arial,Helvetica,sans-serif]New single wire alternator [/FONT]​

[FONT=Arial,Helvetica,sans-serif]Edelbrock 750 carburetor [/FONT]
[FONT=Arial,Helvetica,sans-serif]Edelbrock chrome air cleaner (with K and N filter)[/FONT]​

[FONT=Arial,Helvetica,sans-serif]Brass freeze plugs [/FONT]
[FONT=Arial,Helvetica,sans-serif]Stainless steel bolt set[/FONT]​

[FONT=Arial,Helvetica,sans-serif]Stainless steel 4? risers[/FONT]
[FONT=Arial,Helvetica,sans-serif]GLM aluminum manifolds[/FONT]​

[FONT=Arial,Helvetica,sans-serif]Sherwood motor mounted raw water pump.[/FONT]

The point is, you have a good start there. 7.4's are no longer "cheap" motors. Winter is coming. Pull the motor out. Get a proper matching pulley kit. In the motor install new rings and bearings and hone the cylinders. Last get some new manifolds and you will have a almost new motor that will last for years to come. ​