anyone, I have an unrelated MB question
 

I'm posting this question here because I think there are quite a few good mechanic that can answer a question, here it go's.....

Recently, I was hired to install a rebuilt marine engine into a boat.

The old engine had thrown a rod. It was a late 80's GM 350 CI gas engine. We ordered a long block replacement that was a rebuiid. I transferred all parts including water jackets, intake manifold, carb, fuel pump transmission, etc.

The owner ran the new engine not realizing that oil was leaking out from around the oil filter. It all emptied into the bilge all while he was operating the engine and running it at about half speed, about 2000 rpm. All of a sudden the engine stopped and now it is seized. If I click the starter off and on real quick, I can see the flywheel turn but only a little.

I would like to think that I need only remove the crank shaft, pull the pistons, send the crank out to be turned, buy 2nd oversize main, rod, bearings, I'm not shure about wrist pins, and reinstall.

I base this on hope that damage is localized only to the bearings.

Can anyone with knowledge about this type senario give me advise?

Sooty Taillight:)

I would not be surprised to find some cylinder/piston damage after this scenario.

There is no way to tell with out tearing it down... it could be full of surprises...rangeing from extreamly pleasent to very very miserable...but if it was me I would want to look at everything very closely...

I don't think I have ever seen an engine repaired after running out of oil untill it seized...but I'm not a mechanic either...

Generally a motor doesn't "seize" from the rods and mains getting stuck. It seizes from the pistons getting hung up in the bores. Likely the motor is toast. Good thing that SBC's are plentiful and cheap. RT

That's the hot end of the engine with no oil pressure. I would bet they are a nice blue color now.

If it ran out of oil faily quickly, the damage is likely to be in the crankshaft area. If you find that this is the case, don't stop there. Completely tear the engine down. Don't expect everything to be pefect in this "rebuilt" engine, anyway. More often than not the rebuilds are simply re-ring and -bearing engines.

Expect a spun crank bearing or two. Look closely at the cam for hot spots on the bearing lobes. Lifters are likely "toasted."

The engine is probably toast, marine engines run under a lot more load the car engines, think dump truck pulling up a steep hill. Will the company that you bought it from work with you and maybe give you a better price on another? Was it Recon Marine? They seem to be pretty good.

If the engine is possibly toast, then it wouldn't hurt to just try to pour a bunch of WD-40 into the cylinders and let it soak for some time and then try to see if it'll run run after soaking it. I've saved some 2-stroke engines that way but a SBC is a far cry from a tiny 2-stroke.
I've also heard that pouring brake fluid in a stuck engine can unseize one but I've never tried it.

That scenario reminds me of the 12V-71TI's in the ferries that I used to run. Apparently, after an oil change, the filter housing did not properly seat and the engine promptly disposed of its 12 gallons or so into the bilge. Now, since we are talking about an engine that cost, at that time, over $35,000., there is an alarm in the pilot house that warns, audibly, of low oil pressure. The problem with the alarms is that the captains turn them off below 700 rpm because they go off due to low pressure at idle. So, the alarm is off and the captain makes it out of the marina, hooks up, and goes about four minutes and the engine just shuts itself down. Naturally, he never put the alarm on and never knew it was out of oil.

It actually started when it was returned back to the base. I was there for that event. Had a very rough and lumpy idle. The mechanic knew it was toast. Pistons, rings, liners. The crank, however, was OK. 40 hours of labor for two men which could have been avoided for want of a simple alarm that does what it should, without the need to turn it on and off.

So, if the 12V71 is any indication, the most likely culprit is going to be the pistons, rings and cylinders. Don't have the luxury of liners there so the engine probably has to come back out.

Did similar safety with all my inboards. I always wire an ignition relay through an oil pressure switch. No start without pressure, no run without pressure. Did the same relay setup with more than a couple of cars, too.

you'll just have to yard it out of the boat and tear it down to inspect the damage, then weigh fixing to replacing the engine. also so it don't happen again, need to find out why the oil filter didn't seal properly. just won't know till its taken apart, it can go eirther way.



chip

That is a very good concept. If you think about it, what possible good can an oil pressure gauge do for you if one of the oil cooler lines fails at 3000 rpm? How often do you look at the gauge? If you scan them every three to five minutes, you are doing real well IMHO. That amount of time is forever, as you all know.

Makes the term "idiot light" seem not so stupid after all, especially if it is used with a gauge.

You can buy a big red oil light that the drag racing crowd uses. Its really big and bright so as to catch your attention..... I think the sensor can be adjusted too. Most speed parts places have them. RT