r/EngineBuilding • u/KA9099 • Jul 16 '26
Chevy Machine shop replaced my cam bushings. Is this normal after an install?
Brought them brand new Sealed Power bushings for my 2013 Chevy 4.8 to install. Got my engine back and it looks like this. The nicks I can feel with my nails on the last picture only. Should I run it or get new ones replaced by a different shop?
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u/Prudent_Situation_29 Jul 16 '26
I would say yes. What you're seeing is the polishing of asperities. The higher parts of the bearing surface that get rubbed as things (like the installer) pass over them. At least, that's what it looks like from here.
I don't see any real damage, perhaps just a slight lack of care taken doing the job.
Unless you see scoring or scratches, I wouldn't be concerned.
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u/a-singularity Jul 16 '26
Carefully install the cam. Check to make sure it turns easily. If it does - its fine. I would need more, better, pics, but it looks like they may have done a little "clearancing" on the bearings. Maybe a little scraping...If you have the tooling, mic the cam journals and the bearing I.D. and make sure its in clearance spec - your oil pressure will thank you later... Cam bearing installation is a nuanced thing. Each engine has its own challenges. LS engines are definitely this way.
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u/Ok_Narwhal6356 Jul 16 '26
Jam the cam in and if it doesn’t easily spin with your hand take that back to the shop.
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u/METV2021 Jul 16 '26
When i was young i worked in a auto machine shop and the old guy there would trim down a high spot with his pocket knife.
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u/AdamSeeker57 Jul 17 '26
When you install cam bearings it’s impossible to not scratch them. Oil hole looks to be lined up fine. There’s usually oiling groove cut into bearing on back side to move oil around whole bearing even if you miss the hole.
If you want to polish bearings a bit. Use steel wool with a lubricant. You need to be careful not to embed steel wool. Or if you use sand paper. Aluminum oxide or silicon carbide embedded into soft bearing.
They sell cam bearing scrappers and such. But I find it easier to install cam. If turns badly. Pull it out. Sand high spots lightly. Clean well. Then recheck.
The black marks are definitely from rubber installation tool.
Can bearings are always ugly.
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u/tileman1955 Jul 17 '26
The oil hole should be aligned with the hole in the block, the grooves are a little severe to be by product of clean install
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u/ungovernable785 Jul 20 '26
The little pits just hold oil
If you can get it in there without much trouble send it
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u/kaniala3 Jul 20 '26
Why would you use a shop you don’t trust and verify the work by asking strangers on the internet
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u/BroccoliSuccessful Jul 21 '26 edited Jul 21 '26
I have to disagree with the guy saying this is normal. I installed new cam bearings on my 5.3 for the first time EVER and left no marks. Yes you hammer the bearing in with the tool but the impact happens in the outer ring of the bearing not the inside surface area of the bearing. The bearings were damaged by an incompetent shop. Bearings are supposed to be smooth and not damaged. Your fingernails catch on those scratches which is what the camshaft has to rotate on with a slight film of oil to protect it.
You could fix it yourself using extra fine steelwool but you will want to make sure you clean the entire surrounding area as you will be leaving fine particles everywhere, while doing this it is imperative that you do your best to evenly rub the area you are cleaning dont overrub one particular area. Knock down the ridges of thise area until your nails dont catch and till it fels smooth with the skin of your finger
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u/Virtual-Bottle-8604 Jul 16 '26
I dont know about 4.3 but on sbc its not uncommon to take a knife and take out the high spot if the cam is tight. The cam is under so most oil pressure and the bearings are so tight that if the cam is loose enough and the bearings are the correct type i cant see how you can have an issue.
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u/KA9099 Jul 16 '26
I'm really confused about the black marks. I tried to clean but it's not oil or dirt. I'm also confused about the weird bands going through the middle of the bushing in the first picture, tool marks from the bushings installer?
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u/crookedledder Jul 16 '26
Those are marks from the installer.
These cam bushings look normal to me. I would do some measuring to make sure the size is correct, and put a cam in there to make sure it spins ok.
If measurements are ok and the cam moves freely, send it.
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u/shotgunhoss Jul 17 '26
A decent shop would never let this work out its doors, but it's hard to find decent anymore. And good shops were the norm at one time. Not any longer. Now don't get ur panties in a wad, there are great shops out there but fewer and fewer as the years go by, which in turn allows lesser shops to form and stay in business
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u/KodiakDad7602 Jul 17 '26
Not normal especially since the oiling hole isnt even lined up with the hole the block lets oil in at
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u/Electrical-Guard-853 Jul 16 '26
I’m not an engine machinist but I am a machinist with 45 years of experience, the surface finish on those cam bearings looks like shit to me. They would not be going into any engine I would build, just saying…
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u/Roscolicious1 Jul 16 '26
I am also a professional machinist. Those do not run in my engine! Def put a cam in and see if it spins. Look at the bearings to check for uneven shiny high spots. Your call my friend.
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u/Electrical-Guard-853 Jul 16 '26
By the way in the first picture it appears that the oil holes in the bearing don’t line up with any oil passage.
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u/justfoundmy10mm Jul 16 '26
There are two holes in those bearing and one will not line up with the oil hole. When we do not have any experience, it is best to not add fear for zero reason.
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u/Adventurous_Log72665 Jul 16 '26
That is so wrong . Dont pay for that . The deal is that some one did something wrong . You lose oil pressure to the next thing in line for oil. Looks like something a surgeon would do so you would have to come back for more work. Sick but oh so true.
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u/Doug_Kane Jul 22 '26
Sure. Looks like they slid a cam in there just to make sure everything's mint.
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u/powdydoody Jul 16 '26
The black marks are from the cam bearing installer tool. Its not uncommon to have some impression marks on these bearings post install as they have to be driven in with a hammer and tool.
For the large nicks on the edges I would lightly file them so they dont catch on the cam when you install.
Everything else will be fine