Problems with cam installation

[TXcharger70]

OK so today me and a buddy got the all the rotating assembly put together on my 383 stroker build.  I had the machine shop install new cam bearings and so fourth.   Well we went to install the new cam and It goes in about 95% then tapped it in but when we did this the cam will not rotate freely. What can we do? I have read about scraping the bearings but can this be done with the rotating assembly in place? I should have check everything before hand but i some how did think i would run into this problem. What is the best solution?

[Challenger340]

The "fit" when installing new BB Mopar cam brgs can be notoriously OFF, requiring clearancing of the Brgs as NORMAL PRACTISE upon installation, until a Cam slides in properly without binding.

IMO,
I dis-assemble the shortblock and take it back to the Shop for correction. They've only done half the job.

If you are determined not to dis-assemble the shortblock, and want to attempt repair on your own, you may try the following,
albeit,
this is a P.I.T.A.
It involves making up a Cam Brg Polisher, because you will not be able to actually "scrape" the Brgs with the assembled Rotating in the way and the limited visibility. Scraping with the rotating already installed, would invariably introduce too much debris and kill the brgs without "knowing" where to scrape.

*Knock out the rear Cam plug at the back of the block
*Take a piece of 3/8" Redi-Rod about 3 ft long
*Cut a slot approx 1" deep lengthwise in one end of the Redi-Rod
*Cut a strip of ScothBrite abrasive Pad (Maroon) about 1" X 5", then slightly spread the slot and insert the Scothbrite pad centered, then squish back down in a vise to retain it.
*Use an Electric Drill as a driver. As you use the drill to turn the pad in the brg, the Scothbrite will fold around itself making a nice round brg buffer.

Now, rotate the Block upside down on the stand or on the Bench, you'll have to "look" what you are doing from below through the Lifter gallery with "limited" vision.
Dip the pad in Solvent fequently as you polish the Brgs.
Start with #5 brg from the rear, easiest to get at, Polish, blow clean with brake clean, lube again, then retry the Cam.
repeat,
until you figure out which brg is causing the poor fit and is "tight".
Usually it's #1 or #5 brg, the easiest to get at from front or rear, but it could be any of them.

Some Tips;
Keep the Block upside down, to prevent any debris from entering the Cam Brg Oil holes.
Try & Install the Cam far enough FIRST, so you can "see" the tight spot with a flashlight. It will be manifested by a dark spot on the Cam Brg, THAT is where you wish to polish first.

Good Luck

[TXcharger70]

I am pretty sure it is #5 brg it just sucks to have to disassemble everything again? I guess it cant be too bad. i didn't feel like taking everything apart because it took so long to file fit the rings yesterday and then assembly everything but, i don't have to file rings again so it won't be so bad.

[John_Kunkel]

I don't like the idea of using any abrasive (including Scotchbrite) on bearings, too much possibility of the grit being imbedded in the soft bearing material.

You can make a cam bearing reamer from an old cam; using a hacksaw, cut a diagonal slit in each bearing journal and rotate the cam as you install it. The slits will cut away high spots in the bearing, if the bearings are still too tight the slits will show where the remaining high spots are and they can be scraped with a bearing scraper, a tool made for this job.

[Challenger340]

I don't like the idea of using any abrasive (including Scotchbrite) on bearings, too much possibility of the grit being imbedded in the soft bearing material.

You can make a cam bearing reamer from an old cam; using a hacksaw, cut a diagonal slit in each bearing journal and rotate the cam as you install it. The slits will cut away high spots in the bearing, if the bearings are still too tight the slits will show where the remaining high spots are and they can be scraped with a bearing scraper, a tool made for this job.

I don't like the idea of using the Grooved Cam Scraper in an assembled Engine, too much possibility of the cuttings being lost inside.

I only use my Cam Scrapers for initial fit, them follow up with the Scotchbrite Polisher for final fitting, I think pretty much ALL actual Machine Shops do it the same as far as I know.
The Cam scraper, THEN, a scothbrite polish for final, and you are probably not that far off.

The Scothbrite DOES NOT transfer or embed any material, far safer than the Cam scraper by itself.

[TXcharger70]

Most of you would just disassemble and fix or would you say its safe to attempt to fix the high spots while it being assembled?