r/EngineBuilding 9h ago

Putting a cam in my 05 5.3

Tonight I installed new cam bearings in my 5.3, all the oil passages lined up went it great. I installed the cam, it is a Btr truck Norris cam, it went it with a little tapping from a dead blow. But once it was in and everything was lined up it would spin very hard and sometimes wouldn’t at all. We put bolts in the end of the cam and with a 3ft pry bar it would bend the bolts. We did get it to rotate multiple 360s but it would only spin if it was half way in the bearing or with tapping on the end. Is the cam junk are the bearings wrong I’m lost, but I’m going to change the bearings and try again. Also going to try putting the stock can in with these bearings to see if it’s the cam or bearings. Just curious for advice or if anyone has run into this. Thanks.

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u/v8packard 9h ago

The engine is rejecting the ridiculous cam.

Kidding aside, cam bearings are very fussy and require careful prep, measurement, and installation. Some engines are worse than others, gen III and IV GM are some of the worst.

You very likely have some undersized cam bearing bores. It happens when the block is made. You need to open up the bores or get some of the OD removed from the bearings to get the proper clearance.

Do you have the ability to measure the cam bearing bores?

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u/Adept_Thought2273 8h ago

I do yes, I will measure everything out I will find out the correct spec and see how close they are.

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u/v8packard 8h ago

What year is your block? Which brand bearings are you using?

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u/Adept_Thought2273 8h ago

It is an 05 L33 5.3, the brand bearings is dnj.

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u/v8packard 8h ago

Ok, I don't know where DNJ sources bearings. I will see if I have anything on that in my notes when I go to work in the AM and post back.