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100 hour bearing failure in '84 454/350hp

Tim King

New member
I am perplexed about my freshly re-built (only 100 hours ago) 350hp 454. I baby these things after spending $$$$ on rebuilding my starboard engine. Oil pressure was always 40 to 60 PSI, water temp was 165-170 on a closed cooling system. And it was never run low on oil. I check my engines every time before and after I run them. I would love to hear any theories on WTF happened.CIMG9496.jpgCIMG9498-001.jpg
 
hard to say based on the little bit of info you provided....

looking at the second pic, the camshaft doesn't look spectacular either.

how did the other rod bearings look? what do the main caps look like? who did the assembling? who did the break in & what procedure was used? what oil was used?
 
I used Brad Penn 30W break-in oil per the engine builders reccomendations. After the 20 hour by the book break-in period, I used Delo 15W40 with RedLine zinc additive, Baldwin B2 filters and changed after 50 hours. Steel crank, full groove mains, and yes, the mains are trash too. This engine had not been run above 3500rpms EVER. Every other part in the engine and heads look perfect. I did use a brand new oil cooler as well. Of course, its out of warranty, but the engine shop has agreed to look it over and may help out depending on their findings. They have a great reputation and have been in business for 25 + years. Just like they said, this is not supposed to happen, but humans are involved. Supposed to have been a .002 clearance on all bearings. Pretty much ALL the bearings looked like this one. For sure, going to test the oil pump. The pump strainer was the proper distance from pan bottom, not a high volume pump, and the pickup screen was tack welded in place.[FONT=lucida grande, tahoma, verdana, arial, sans-serif]

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All bearing shells looked like this? If the mains are also involved, that tends to point to low oil pressure for all. The first stop for the filtered oil is the rear-most main bearing. How does it look?
Edit: if the rear most main looks good and the shell is NOT upside down, then the rear drilled passage in the crank may be plugged, blocking the oil to all the rod bearings and the mains 2, 3, 4, and 5.
 
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0.002 is a bit tight on the rear main bearing but would depend upon the bearings they used...I would also suspect your builder assembled the entire package and did the cam break in procedure...if so, I'd be asking them the WTF question...

If you put the assembly together, did you plasti-gauge the clearances? Was assembly lube used on the rotating assembly? Finally, was a priming tool used to pressurize the oiling system before the engine was fired?

If ALL the bearings were trashed, I'd lean towards somebody got the wrong bearing set(s), the bottom end was not assembled correctly, or something else in the "human error" category...
 
The engine machine shop assembled all internals. I received an "Engine run simulation quality control inspection" statement with the rebuild, saying oil pressure was 48, oil flow 49, galley plugs "OK" compression 160-165. I know that when my mechanic and I installed it back into the boat, we used a tool attached to a drill to spin up the oil pump for a full 2 minutes, and the engine showed 40 + oil pressure the instant it was started. All the bearings are trashed. The short block was delivered back to the engine shop this afternoon and they are taking a look. I'm going there tomorrow in person for some answers to my "WTF" question.
 
Spun bearings are caused by one (or both) of two things: no oil pressure, or not enough bearing clearance.

Shops tend to assemble engines WAY to tightly, thinking they'll sound nice and quiet, but that causes far more problems than being a bit too loose (which knocks a bit on start up).

I suspect the clearance was too tight since your oil pressure was fine.

Jeff

PS: I always used at least .003 clearance on my reace motors and never spun a bearing.
 
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