Cam Bearings too tight, any suggestions??

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360duster

360duster

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Hi Guys,

few weeks ago i put in new cam bearings in my fresh block. Test fitted it with a used cam, checked out ok, spinning freely. Today i got my new cam and just for fun i tried it ......no chance to get this one fully into the bearings, maybe 2/3 of the way and then it´s stuck. I removed it and saw in two bearings some marks where it stuck.

So this means the bearings are little too tight. I checked the journals at the old and the new cam, not very much difference (it seems enough to give me problems).

Is there a way to save this bearings or is my only chance to put new ones in? Any help and suggestions appreciated, Thanks in advance!

Michael
 
Take an old core and cut diagonal slots in the journals with a hacksaw. Then insert it and spin it. This will slightly oversize the bearings. Clean it up and put the new cam in and try again. Should fit a lot better.
 
First who installed them.second If it was me I would take them back out and see if there was any dirt or debris,reclean and install new ones.This is something you don,t to play around with.
 
Don't let someone talk you into reusing them after they have been removed. When they are installed they shrink to fit the bore size.
 
Thanks guys, that´s what i thought about, using a scraper carefully. I installed the bearings with care, no dirt inside.

Is this a common problem? The tool i made is a long shaft with different diameter drives, made some other blocks with it (also new cams), worked good until this one.

I´ll give the scraper (or razor blade) a try, thanks!

Michael
 
yes its common but the shops most times fit the new cam in....and most folks leave it alone and don't stick another cam in.

A used cam could be bent/warp, just a thought
 
I went to install my cam and one bearing had a tight spot. I just used some Dykem blue on that bearing reinserted the cam and found the small area that was rubbing and used the bearing scraper in that tiny area. Cam turned easy after that. Jayson
 
Right on Jason. You can also use an old cam and groove the bearing surfaces
to ream them for clearance. I donated my original cam to my machine shop for a cam bearing fitting tool. It doesn't take much. toolman
 
Yes, tight fit with a new cam bearing installation is common. The fix is to carefully remove enough material for a perfect clearance and fit. As mentioned, use a bearing scraper or a purpose built reamer. If a machine shop installs the bearings they size the inner diameter too, so a lot of people never know they were snug on installation.
 
Bearing shavers or knock them straight cause a lot of times they are just installed crooked.

Always check them as you go, like after the 2nd bearing you should slide the cam in to check, then install the next and so on.
 
Good advice here, if i end up using a new set i´ll try each one after installation. Don´t think they´re installed crooked but will check it again.

but first i try the scraper or cut a old cam - have one laying around with some wiped lobes - perfect candidate for this....

I will let you know if it works for me!

Thanks

Michael
 
Hi Guys,

the method with the old cam / diagonal slots worked good, with the help of a little lapping compound and my cordless drill the tight spots went away......now the new cam fits perfectly!

Thanks @ all for the "how to".....

now i have to clean up this sh..:-D

Michael
 
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