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I was wondering if someone may have some ideas on what could have happened to my engine? It is an older rebuilt 283 Chev, I have been driving it on short trips for the better part of this year and fall of last year.I decided to take it on a good cruise down the highway, I was traveling at around 50 mph all was going well, temp ok, oil pres. ok, power ok and then after about an hour of driving I heard a bit of a squeal, then lost most of the power from engine and the oil pressure dropped off about to 3/4 of the running pressure. I had it towed home and when I rolled it off the flatbed I started it up to put it away and it ran a lot better cold but it sounded rough. There was no fluids leaking from any where. Tonight I just removed the rocker covers and all looked intact and no metal filings in the oil there, tomorrow I will run a pressure test on each cylinder and see if that is ok. But I was wondering if anyone had any ideas of where to check after that? I was thinking the water pump but there was no fluids from the pump and I don't see that messing with the oil pressure and power of the engine.
Anyone?

Thanks in advance.

Ken

Not too sure if this will help but it was a fresh rebuild 4 years ago, I ran the engine for maybe an hour or two moving it in and out of the garage and then while the body work was being done it sat in my garage for a couple of years, intake was sealed. As I said the truck was put on the road last fall and it ran well in the city for approximately 50 to 100 miles.

Before you run the engine any more, I'd suggest draining the oil and removing the filter. Strain the oil through a piece of T shirt material or something similar, and cut the filter open. Look for any sort of metallic debris. That squeal and oil pressure loss sounds suspiciously like a failing rod or main bearing, and if you continue to run the engine, it's likely you'll trash the crankshaft.

Older 283's from the late 1950's had a nasty habit of getting cracked piston skirts, but those just made a light knocking noise- - -no appreciable power or oil pressure loss.
Jerry

Thanks Jerry, that will be on my "first to do list" tomorrow morning. I will return with the results.

Ken

Jerry's diagnosis is the first thing that popped into my head also. Only thing I could think of that would drop the oil pressure. Good luck.

If it's not too difficult, you might also consider dropping the oil pan. Check the pickup screen as well as the low spots in the pan.

cm

Just a thought. But since this same thing happened to me a very long time ago. Pull the fan belt off. Turn the fan by hand. Sticky? Rough? Or just stuck? No leaking no noise, and bang. The water pump into the radiator. Different motor, and different car, but the things it was doing are the same, limited RPM, Lowered oil pressure(I think the drag on the engine caused that) and last, but not least..a short squeal. The noise was a combination of bearing death, and major belt slip. If I had stopped then. I might have saved the radiator, fan, pulley as well as the front half of the water pump(Buick V6 in my old Jeepster). Fastest radiator drain I ever saw. It even impressed the Highway Patrol car behind me. No issues with the law. And he had a tow for me before I rolled to a stop(nice guy). Jeep Radiators are about as hard to find as our truck radiators are(spendy too). Any way, If the oil is clean, and the filter is clean, I would for certain check the water pump. Last year we put a 235 into a 48 Chevy sedan. Went the shortened pump shaft and...then lost the press fit for the fan support. That cost a fan, and radiator as well. Why the machine shop never said any thing about the easy press I don't know(I don't take parts to them any more) Would have been nice to know. Long story I know, but check that water pump, please?