Bearing issues on rebuilt engine

Messages
6
Location
Long Island
Hi, This is my first post here, but I've been reading these forums for a couple of years now. I recently installed a rebuilt 5.7 long block in my boat to replace one of the engines that had low compression due to a leaking riser gasket. I broke in the flat tappet cam with 15w40 and a bottle of EOS by running it 2000-2500 rpm's for 20 minutes. I changed the oil and filter, then followed the rebuilder's recommendations on breaking in the engine. At this point everything is good with the engine. After the 10 hour break in, I was able bring the RPM's up and plane off the boat. When running at 3000 rpm's the oil pressure on the new engine started at 50 psi, then slowly dropped and settled at 25 psi. If you let this engine cool down for a bit the oil pressure is back up to 50 psi, then the pressure drops once the oil heats up again. This is with Quicksilver 25w40 conventional oil and a bit of zddplus for the zinc. I decided to see if 20w50 would bump up the oil pressure a bit. The oil that came out of the engine didn't look good, it was a glittery metallic bronze color. I also cut open the filter and found it filled with silver metal flakes. I know this engine is toast and needs be rebuilt...again. The weird thing is this engine runs perfectly and its not making any noises. What would cause this failure? I always thought you would get a knocking noise when the bearings were going. Thanks, Sean
 
Messages
2,307
Location
SD
First, welcome! I don't have any suggestions other than to contact your rebuilder. Sure sounds to me like you did everything right during break-in. Disappointing, for sure! Let us know what the rebuilder has to say.
 

Mullady76

Thread starter
Messages
6
Location
Long Island
Quote
I don't have any suggestions other than to contact your rebuilder. Sure sounds to me like you did everything right during break-in. Disappointing, for sure! Let us know what the rebuilder has to say.
That is another problem. He is in Florida and closed down for a couple of weeks due to covid. I've called, emailed, and texted him and I get no response, so I'm on my own for now. Right now i leaning on buying a new long block and swapping everything over to minimize my down time.
 

Mullady76

Thread starter
Messages
6
Location
Long Island
Duffyjr, My problem is this is a twin engine boat and the other engine is still strong, so I'd like to keep a matching set. I found a company that is selling new base engines (brand new long block with the oil pan, balancer, and water pump already installed)
 
Messages
17,108
Location
NH
Did the oil after the first oil change look silvery too, or more like regular oil? But the fact that you changed it before running hard should have gotten most of any assembly lube out, so, even to me this sounds bad. As to why, not sure. Too much bearing clearance and then when it heats up, the thinner oil can't keep parts apart? Poor machining and it simply self-clearanced? shrug Would be interesting to hear more qualified opinions. I'm kinda surprised that it was fine under light load and then seemingly ate itself when pushed hard. Cooling problem and it's running hotter than thought? at least in some parts of the block. It sounds like this wasn't your core being rebuilt, just want to rule that out.
 
Messages
25,439
Location
Upstate NY
Its not rocket science to machine a crankshaft for oversize bearings. They have been doing it for decades. And the large engine remanufacturers have the expensive machines to do it precisely. I think you need to keep pressing the company that did the rebuilding. Can you visit the place and discuss in person? I had a reman engine that was not done properly. It was shipped back and a different one was sent. The reman company paid for most of the labor for the removal and second install.
 
Messages
1,967
Location
USA
Originally Posted by Mullady76
Quote
I don't have any suggestions other than to contact your rebuilder. Sure sounds to me like you did everything right during break-in. Disappointing, for sure! Let us know what the rebuilder has to say.
That is another problem. He is in Florida and closed down for a couple of weeks due to covid. I've called, emailed, and texted him and I get no response, so I'm on my own for now. Right now i leaning on buying a new long block and swapping everything over to minimize my down time.
That tells me what I need to know right there. Get your documentation in order ( hopefully you paid by CC)
 

Mullady76

Thread starter
Messages
6
Location
Long Island
The first oil change didn't look bad. The oil was dark, but i didn't see any metal. I figured HDEO mixed with all that assembly lube, plus a bottle of EOS turned the oil dark brown.
 
Messages
1,034
Location
Arizona
It would have been better to get a local speed shop to do the rebuild If the rebuilder has a reputation make sure he knows you'll make waves online if he ignores the problem. Any engine builder should be able to do a teardown and see what they did wrong at this point its not blown. I had a rebuild before at a local speed shop. One of the cam bearings was cocked ...they fixed at no charge
 

Mullady76

Thread starter
Messages
6
Location
Long Island
At this point I'm buying a new long block and will swap that in so I don't lose the entire season. Once I get the new engine, Ill get the boat hauled and it shouldn't take me any longer than a week install it. Hopefully the builder gets back to me and I can this engine fixed and drop it in the other side during the off season or at least get my money back. Though I have a strong feeling that is not going to happen, then I'll make waves online.
 
Messages
25,838
Location
PNW
Originally Posted by Mullady76
The first oil change didn't look bad. The oil was dark, but i didn't see any metal. I figured HDEO mixed with all that assembly lube, plus a bottle of EOS turned the oil dark brown.
Sounds like maybe some tolerances were too tight, and after the engine was put under load at 3000 for awhile, and things really heated up, metal-to-metal contact occurred and it was all down hill from there. Or it's possible there was some kind of oiling system problem going on and not providing adequate oil flow and lubrication to something.
 

Mullady76

Thread starter
Messages
6
Location
Long Island
I'm getting an analysis of the oil that was just changed to CYA. Yes there was an oil pressure issue that only showed up after the engine was put under load and the oil heated up and thinned out. This engine doesn't have an oil cooler, so the oil temps under load are probably pretty high, which is why I used quicksilver 25w40.
 
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