Possible blown head gasket or cracked component?

[ohmthis]

Hi all, I bought a boat knowing it was damaged from an improper winterization (it bought very cheap). It has a 5.7 two barrel, boat is a 1996.I checked compression and number one is down to 60 psi, number two 110 psi, all the rest 150-165 psi. I took the manifolds and risers off and they look good with no visual cracks. Cylinder 4 and 5 had water in them. I want to preform a test on engine cooling system to see if it has any major leaks. Any advice as to how to do this?plug hoses and put air in or use a vacuum pump? Thanks

 

[achris]

Re: Possible blown head gasket or cracked component?

Close off the hoses that go to the exhaust manifolds and then with a pressure gauge installed somewhere in the cooling system (end of one of the manifold hoses would be the easiest) pressurise the block/heads/ through the water inlet hose.

Chris.......

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

Chris, what psi should i put in and should it hold it indefinately? I was going to cap off the manifold hoses and use a innertube cut and tied??? To use a pump on. Drill and screw a gauge on one of the end caps and go from there.

 

[achris]

Re: Possible blown head gasket or cracked component?

I'd go to about 10 to 12 PSI. If it's going to leak, that's the pressure it would do it at. If it holds pressure for 30 minutes, you'll be fine... I use some plastic garden reticulation fittings to cap off all the hoses.. I have one that's threaded and I screw in my drive pressure tester into it. I have that set up so I can introduce the pressure through the tester...

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

The test was an epic fail. The setup was good and I double and triple checkedall my connections. It never held any type of pressure. So now the engine comes out!!!!

 

[Bondo]

Re: Possible blown head gasket or cracked component?

Hi all, I bought a boat knowing it was damaged from an improper winterization (it bought very cheap). It has a 5.7 two barrel, boat is a 1996.I checked compression and number one is down to 60 psi, number two 110 psi, all the rest 150-165 psi. I took the manifolds and risers off and they look good with no visual cracks. Cylinder 4 and 5 had water in them. I want to preform a test on engine cooling system to see if it has any major leaks. Any advice as to how to do this?plug hoses and put air in or use a vacuum pump? Thanks

Ayuh,.... Welcome Aboard,.... No Surprises I guess,... Ya knew it was an anchor when ya bought it,....

A GM Goodwrench crate motor will get ya back on the water,....
Go for the Vortec heads, 'n 4bbl. carb/ intake,....

Where yer ya hearin' the air excapin',..??

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

Bondo I tried a hand pump and it would never pump up. I checked the connections again and looked for any missing caps or openings. I pumped again and again nothing. I connected an air line up to it and I couldn't hear because of the compressed air rushing in.

 

[Bondo]

Re: Possible blown head gasket or cracked component?

Bondo I tried a hand pump and it would never pump up. I checked the connections again and looked for any missing caps or openings. I pumped again and again nothing. I connected an air line up to it and I couldn't hear because of the compressed air rushing in.

Ayuh,.... I use a compressor, 'n regulate it to 'bout 15 psi,....

I still think ya already know it's Junk,......

It's time to get past the gold diggin', 'n do what ya planned to do, the day ya bought it,...

Tear it down, clean up the Marine dressin's ya need, 'n Hope they're all in serviceable condition,...

The exhaust manifolds will need pressure testin', before ya even Think 'bout usin' 'em,...

I laid out a viable plan above,...

If ya really wanta Fly,... Go for the GM HT-383,.... 4bbl. carb, 'n matchin' manifold of course,.....

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

Even though the manifolds and risers look good (visually), I will be getting them pressure tested. If the engine is complete junk (more than likely), a vortec headed engine will be sitting in it. I wont go as big as a 383 because of the alpha outdrive.

 

[Watermann]

Re: Possible blown head gasket or cracked component?

I would pull the motor and then the heads so you can lay eyes on the cracked block. You could get her going strong again with a short block and have the heads rebuilt for a fraction of the cost of a crate.

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

Watermann, the plan is a vortec headed long block. I know i could have less money into a short block and rebuilt heads, but I still wouldnt have the extra power and I'd have a warranty too. Some short block warrantys are nothing to 6 months. I got such a steal on the boat that I can off set the cost of a new engine and still come out way ahead.

 

[achris]

Re: Possible blown head gasket or cracked component?

Watermann, the plan is a vortec headed long block. I know i could have less money into a short block and rebuilt heads, but I still wouldnt have the extra power and I'd have a warranty too. Some short block warrantys are nothing to 6 months. I got such a steal on the boat that I can off set the cost of a new engine and still come out way ahead.

:thumb:

BTW, Alpha drive is good to 300hp. Get a 383 and have it only make 300hp and it will have so much bottom end torque will will blow your mind...

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

One question, since i will be going to a roller engine, doesnt the distributor gear need to be changed? This is the second chevy ive played with, but for roller cams were very hard and would eat a bronze gear. Thanks!

 

[Watermann]

Re: Possible blown head gasket or cracked component?

Watermann, the plan is a vortec headed long block. I know i could have less money into a short block and rebuilt heads, but I still wouldnt have the extra power and I'd have a warranty too. Some short block warrantys are nothing to 6 months. I got such a steal on the boat that I can off set the cost of a new engine and still come out way ahead.

Most guys come around and are testing stuff with the hope of not spending big money. But hey awesome I love it, chip in a few more clams for some through the hull exhaust with a diverter. Don't forget to come back and show us a picture.

 

[achris]

Re: Possible blown head gasket or cracked component?

The early gear supersedes to the later one. Not sure exactly what the difference is... Easy enough to change... The rest of the dissy is the same.

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

Chris, this boat is for pleasure and as bad as i would love for it to run like my old outlaw, i want it to start everytime and not tear things up like that boat did (560hp can do that). I will check and report back as i think the gear needs to be "melonized"???
Watermann, thru hulls out the back may be a little difficult, but im digging the side exhaust!!!! Ill document this with pics. I also wish i knew how the boat performed before so i can see what the difference is. Thanks all!!!

 

[Watermann]

Re: Possible blown head gasket or cracked component?

Check out Frisco's Corsa side exhaust with diverter on his Sea Ray with a 7.4 L MC.

 

[ohmthis]

Re: Possible blown head gasket or cracked component?

Got the engine out and started tearing down. I stopped when I found the two big cracks in the block. Illpost a picture when I can. Time to order eveything I need. Lets see, long block, intake, four barrel carb, pressure test manifolds and risers, and a gimbal bearing. Am I missing anything?

 

[MikDee]

Re: Possible blown head gasket or cracked component?

Love that syncopated big block idle! IMO, anything bigger then a 5.0 motor, and ya gotta have some type of mufflers. Side exhaust is better for water sports. Do it up good ohmthis, but be careful with that Alpha drive! :thumb:

 

[MarkSee]

Re: Possible blown head gasket or cracked component?

...Am I missing anything?

With the motor out I would also do a close inspection of the components that get replaced only when the engine is out:
engine coupler, Y-pipe, complete transom assembly including gimbal housing/ring, etc.

Also would be the time to make sure the transom and stringer system is within acceptable limits for moisture content.

Mark