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easy bearings inspection?
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TheGrinder(ofgears)
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Dec 30, 2020, 6:17 PM
Post #1 of 7
(1979 views)
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easy bearings inspection?
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what's the easiest way to check the health of engine bearings? Without disassembling the car or engine? Like, is there a way to use a dial indicator on the crank bolt while you wiggle the harmonic balancer with a prybar to check clearances?
(This post was edited by TheGrinder(ofgears) on Dec 30, 2020, 6:19 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 30, 2020, 7:47 PM
Post #2 of 7
(1969 views)
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Re: easy bearings inspection?
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IMO there is no fixing most engine bearings about all are made to spec ONCE is all you get when new. Anything later is a patch IMO so here's how I tell is simple really.
If vehicle {you said an '06 GM 3800' in your other post) so go with that. If it has either an oil light (red one)for low oil pressure or a gauge either if working catch that when it has NOT been run for a day or more if you are buying feel engine for heat.
Now just see that gauges work with key or format about to start that engine. It should light up the warnings and activate gauges when in "run" only position, key or other start method.
Open hood and window you want to hear also. Turn to start paying strict attention to how fast oil warnings light or gauge responds to a cold start. It's wasting oil pressure if not destroyed from neglect or horrible luck to build up oil pressure first and foremost is measured AFTER pressure build up enough in bearings, so those leak down on purpose to passively lube parts slinging oil around first I'll call that a "prescribed" leak rate then satisfies oil pressure switch to gauge or light.
How long or revolutions did it take? You only get one check not the second try that day! Suks if someone cheated and started a thing you were going to buy for example to cover this up. It should go OUT and have no warning or adequate oil pressure in no time flat means that the "leak down" is to spec which it would be with worn bearings take longer or flicker, jump around if gauge type thing.
You hear engine too with cold start so pay attention to first 10 seconds if knocks or tapping takes even 15 seconds to totally go away.
If good and not fooled by some other problem not really engine at all it's good if out in a couple revolutions. That is so telling of engine health as bearings are line bored ONCE said up top another try later is only a patch not like original new line boring even that only a couple per precise cutting bits so there is no "break-in" for engines anymore the machine work is so good it's ready when new or fails before sold new I hope.
The game is if NG it's NG for too long or many, many more miles with few exceptions that's it engine is on it's way out if buying move on to another unless you get a price that will get you whole, original known checked and good perfect match engine. I don't believe in rebuilt much of anything "machine work" wise to cylinders, bearing journals that make unique noises near impossible to describe more than I just did was enough! :-)
Tom
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TheGrinder(ofgears)
User
Dec 30, 2020, 8:58 PM
Post #3 of 7
(1953 views)
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Re: easy bearings inspection?
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you obviously know a ton about cars, and I think you have helped me out before, but I'm having a bit of trouble parsing what you wrote. it is difficult to understand where one sentence ends and another begins, with all due respect.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 30, 2020, 9:31 PM
Post #4 of 7
(1941 views)
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Re: easy bearings inspection?
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OK,
My fault I'll never get used to computer shorthand.
In short if I can. Oil pressure building up almost instantly is because bearings are good more than anything else. That's seen by gauge or light going out upon cold starts almost never fails tells all.
End,
That near killed me to be that concise - Tom
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TheGrinder(ofgears)
User
Dec 30, 2020, 10:51 PM
Post #5 of 7
(1935 views)
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Re: easy bearings inspection?
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ok, so i had to look up oil engine oil pathways. If i have this right, oil galleys in an engine block will always lubricate the main bearings from the top down, so if there is excess gap in the main bearings, gravity means that the excess clearance will always be at the top, at least on startup, where the oil feed is, allowing more oil to escape out the side. this is an indication that the rod bearings have likely seen much more wear because of being briefly oil starved at startup while it takes time to build oil pressure through the system. this rod bearing wear will in turn allow more oil pressure to escape, accelerating wear exponentially.
would you say that this test is more or less useful than a service history that has all the oil changes?
furthermore, would lack of oil spray coming out of the rod nozzles create enough ring wear that you would start to see absolute compression or leak down numbers come down enough to cause alarm?
(This post was edited by TheGrinder(ofgears) on Dec 30, 2020, 10:59 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 30, 2020, 11:44 PM
Post #6 of 7
(1923 views)
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Re: easy bearings inspection?
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You have a good grip on this already. Oil pressure to top or bottom first will vary. The leak is allowing spun off oil to lube other things isn't identical for all engines using oil pressure.
The idea is some must escape but limited to minimal.
Oil pumps are TMK all mechanical (Google planned obsolescence) rather than maybe electric would be pre-pressured up with oil before you turned a piston engine they'd last too long and piss off stock holders!
It's usually lack of oil changing or type of oil that screws up and wears things out. Add short miles per run time, overheating and add beat the hell out of a thing before warmed up.
Temperature will change sizes of things well thought out is off my pay grade for our things to put up with vs first idea of what we still drive around with is IMO a failure but the best humans could do is a flipping up and down piston and crank what you used is the rotation of it only.
Lube is oil still. Not sealed units quite yet I'll be gone for the permanent engine for lasting forever let's move on (as humans) to something else to worry about.
You've really picked up the idea from the grass roots so build from that. Your famous old totally push lawnmower is splash only (cheap things) still put up with a lot nothing but spark not much else fancy.
Trivia 101: TMK the internal combustion engine was first made by the Chinese using no less than another idea the combusted GUNPOWDER. That dates back many centuries pulled down by Google probably IDK hate this way to learn who did what and when.
So oil it is and it matters totally to anything today like a engine using pistons and crankshaft. Quality counts and changing oil out matters as it gets contaminated with junk or fuel so wear would be fast or faster.
Mobility is a huge expense to most of us mere mortals so pay attention to minimize its impact on your wallet type thing. I do try to keep that cost to zero but it's also tons of my time is unique to my situation. Rare is for transportation to cost me anything but getting old so finding real help myself is a challenge.
Knowing when to bail out helps or cut losses on mistakes or just the wrong one for you. Knowingly passing that on to unsuspecting buyer isn't right just the morality of it - wrong.
I think you've got it. Care for it and try to know what is practical for how long is hard to do hope this isn't the only important thing in your life but it matters,
Tom
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Hammer Time
Ultimate Carjunky
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Dec 31, 2020, 5:30 AM
Post #7 of 7
(1905 views)
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Re: easy bearings inspection?
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Why don't you state what it is that you're trying to accomplish or find out here.
Are you trying to prove something to someone?
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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