Blown BBC - Water in Oil

[cg818]

Happy Saturday guys!

I've got milkshake and this will be my first time trying to diagnose and fix the issue myself. Had the boat out last October and got her up to 98 mph, 6100 RPM, did not miss a beat and ran beautiful all weekend. Was going to list for sale and while going through found the milkshake. Hoping you guys can help guide me along with the next steps for diagnosing and repair.

Motor Info:
489 BBC, aluminum heads, superchiller, 8-71 blower, dual holley 750CFM carbs

Diagnosis so far:
1. pumped out oil and water (9.5 quarts)
2. replaced with 5 quarts cheap oreilly oil and 1 quart marvels mystery
3. Pulled plugs and checked compression
- Cylinder #1: made two readings on this as the extension for the tool probably has a leak. 140psi
- Cylinder #2: 150psi
- Cylinder #3: 165psi
- Cylinder #4: 150psi
- Cylinder #5: 170psi
- Cylinder #6: 140psi, plug looks corroded
- Cylinder #7: 140psi
- Cylinder #8: 140psi
4. I have attached pictures below so you can see the motor, test results, and what the plugs look like

Any and all help is greatly appreciated.

Thank you!
- Corey

 

[Husqy510]

I'm sure others with far more experience a will chime in but probably a blown head gasket on #6. I'd pressurize that hole and see where the air goes. At a minimum the heads have to come off and then it should be pretty obvious. With any luck it's just a gasket.

 

[cg818]

I'm sure others with far more experience a will chime in but probably a blown head gasket on #6. I'd pressurize that hole and see where the air goes. At a minimum the heads have to come off and then it should be pretty obvious. With any luck it's just a gasket.

10-4, yeah that plug looks pretty nasty. Thanks for the input

 

[obnoxious001]

Get a bunch of oil or WD 40 or something in that cylinder ASAP, and turn the engine over by hand if you have not put the plugs back in. If you turn it with the starter motor it will spray all over the place, but try and limit any further rust damage.

 

[cg818]

Get a bunch of oil or WD 40 or something in that cylinder ASAP, and turn the engine over by hand if you have not put the plugs back in. If you turn it with the starter motor it will spray all over the place, but try and limit any further rust damage.

Good idea, I’ll get on that now thank you


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[BamBam]

I'm not discounting the look of the plugs or the compression test, but you also might want to look at your super chiller. You should pressure test it as well

 

[cg818]

I'm not discounting the look of the plugs or the compression test, but you also might want to look at your super chiller. You should pressure test it as well

10-4, what is the easiest, most cost effective way to perform the pressure test?

 

[BamBam]

I think the cheapest way is to remove the pipe thread fittings and place a plug in the outlet. On the inlet you need to place a gauge inline with a schrader valve (like on a tire). They are available. The schrader valve will allow you to charge the cooler with air from your compressor and hold the air in while reading the pressure on the gauge. Then put about 8-10 PSI on it and see if it holds.

If anyone else has a better suggestion please add it.

 

[guest hs]

Check you exhaust riser gasket on the stbd. side.

 

[cg818]

Check you exhaust riser gasket on the stbd. side.

Sorry for the ignorant question, but where the hell is the exhaust riser gasket?

 

[farmo83]

Agree with pressure testing the chiller cores.

 

[monkeyswrench]

Don't know where you're located, but usually truck/fleet supply shops will have the fittings and schrader valve connections.

On the header setup you have I don't think you'd have gaskets/risers. You may look at the headers though, I've heard they can start to corrode and leak.

 

[guest hs]

Don't know where you're located, but usually truck/fleet supply shops will have the fittings and schrader valve connections.

On the header setup you have I don't think you'd have gaskets/risers. You may look at the headers though, I've heard they can start to corrode and leak.

Good point I didn't think to ask what exhaust he had.

 

[SoCalZero]

Is your water to the Intercooler regulated or have a pressure relief valve?

 

[cg818]

Well I kind of went ass backwards and dropped it off for a cover to be made in the meantime. Got some wd40 in cylinder 6 as suggested and will try to start testing/tearing apart next weekend. I have the following to confirm:

1. Check pressure in superchiller
2. Check if pressure is regulated for superchiller and exhaust
3. Check headers for corrosion
4. I think at that point I’ll start tearing things apart

Hope to be able to report back next weekend. Thank you all for the support and guidance [emoji1360]


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[BamBam]

Were you able to diagnose the problem?