Rebuilt Engine bearing wear

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Braeden Clark

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Hello all. My freshly rebuilt magnum 360 was making a strange ticking type noise. I decided to play it safe and drop the pan to check the bearings. Well they don't look great. I only checked 4 tonight and I didn't like any of them. Crank was polished and all bearings were plastigaged. Any help here? Crank still looks perfect from what I've seen. Just the bearings seem beat. I have new rod bearings already but how do you replace the mains in the engine? I've heard some people do it. I'm talking to the machine shop tomorrow morning.
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Braeden Clark said:
Hello all. My freshly rebuilt magnum 360 was making a strange ticking type noise. I decided to play it safe and drop the pan to check the bearings. Well they don't look great. I only checked 4 tonight and I didn't like any of them. Crank was polished and all bearings were plastigaged. Any help here? Crank still looks perfect from what I've seen. Just the bearings seem beat. I have new rod bearings already but how do you replace the mains in the engine? I've heard some people do it. I'm talking to the machine shop tomorrow morning. View attachment 1715930899 View attachment 1715930900

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The rod bearings do seem worse then the mains for sure.

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Honestly they dont look terrible to my eye. And your pics aren’t great but I would (just by looking at the pics) suspect trash in the oil from not being anal about cleanliness on assembly, or maybe the journals are out of round. Do you have a set of mics instead of plastigauge?
 
MoparMike1974 said:
Im not seeing any major problems there.
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After doing a little more research I'm seeing where this may be somewhat normal. I don't really like it but apparently it may not be as bad as I originally thought. I will probably still replace the rod bearings. I'm down here anyway... going to see what the machinist has to say tomorrow
 
What was the bearing clearance when it was assembled?
 
Bottom end usually dull knocky noise. Top end ticky. Plus the timing of the noise is diagnostic too. Those bearings look good as far as I can tell.
 
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TT5.9mag said:
Honestly they dont look terrible to my eye. And your pics aren’t great but I would (just by looking at the pics) suspect trash in the oil from not being anal about cleanliness on assembly, or maybe the journals are out of round. Do you have a set of mics instead of plastigauge?
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I do not have mics but the machine shop checked the crank out and said it was good. They also polished it. And I was as anal as I could be but I probably could have been a little better. Also could have had dirt in the oil passages. Didn't have the block hot tanked like an idiot.
 
I remember your thread about engine noise and I never could hear a knocking in your videos. Is sounded like top end tick or an exhaust leak to me. Did you plastigauge them again this time?
 
TT5.9mag said:
I remember your thread about engine noise and I never could hear a knocking in your videos. Is sounded like top end tick or an exhaust leak to me. Did you plastigauge them again this time?
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I did not plastigage them yet. The one crank bearing I did was still Easily in spec. I might just replace all the rod since I'm down here and already have new ones. The thing that concerned me was a light rattle at idle ONLY when warmed up though. I have a video on that too. Also as far as the tick my trans inspection plate was rubbing the flywheel. So hopefully that gets rid of some noise.
 
New bearings is a good plan while you’re there, but don’t just throw a set in. Actually measure the crank buy a set of bearings to establish whatever clearance you’re aiming for. Good bearing manufacturers make em with extra clearance or less clearance. Bearings are cheap, engines are not.
 

fast forward to 4:00 you’ll hear rod knock.
 
You can shine up your bearing insert surfaces with a dry paper towel, make them look good again. Put her back together.

Apply Lucas Engine Oil Treatment/Assembly lube (the thick stuff like STP) to the bearing surfaces and crankshaft as you assemble.
 
Those bearings look fine.
Plasti Gauge is ok, but most folks just check one spot on a main or journal so they don’t see out of round. And there is a huge resolution and repeatability issue with plasti gauge,, how old are the strips, the temperature they are used at, just for starters.
If you really want to know main and journal clearances, get a dial bore gauge and a set of micrometers.
You can get a good set for a home garage use for around 100.00 for each, lots of you tube videos on how to use.
And, a hot tank is good for cleaning up the surfaces you can see so you don’t rub debris into the build process. But you still need to scrub all block and head and crank oil lines with hot water and detergent and more hot water for a flush after the hot tank to get the internal lines clean.
 
Magnum 360, with a hydraulic roller cam and adjustable rockers???

Those adjustable rockers add a whole other dimension of getting your valves adjusted right.

Hope you have the proper preload set.
Go to zero lash, then preload 3/4s of a turn down.

Just one of those valves Set wrong can give you the ticking.
 
Every single thing John says in post #21 I agree with.....BUT plastigauge is better than NUTHIN and NUTHIN is what you did. I sure wouldn't repeat that this time around. Measuring clearances at assembly is to make sure everything goes together correctly, AND to catch any inconsistencies from the machine shop. It does happen. Without SOME form of measurement, even "crude" plastigauge, you have no idea "where you are".
 
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