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New cam a wee bit tight?

Posted By: Sixgun

New cam a wee bit tight? - 07/22/13 05:27 AM

New comp 274,1 new cam bearing (1st one, dont ask)
cam goes in pretty smooth,gets a tiny bit tight the last 1/2 of the last bearing.
Pulled it back out, wiped off all the red assembly lube,oiled with 30 wt,slid back in, same.
Cannot turn just with fingers,no sprocket installed,
(just a bolt).
Put a small torque wrench on it just to see the breakaway torque,takes between 35-40 inch lbs to get it turning,turns very smooth and easy after that,when you stop,same thing again.
(Cannot turn with fingers at any time, but turns easily with 11/16" open hand once you get past the "sticky" start torque.Position doesnt matter, same no matter where you start or stop.
So what, polish cam journal(s) with light oil and dead 400? Concentrate on the 1st(new bearing) journal 1st?Any more checks I can make?Suggestions?
Thanks,
Bear.
Posted By: RapidRobert

Re: New cam a wee bit tight? - 07/22/13 01:47 PM

I'd say you're OK as is. If anything I'd maybe SLIGHTLY polish that front journal a bit.
Posted By: bonefish

Re: New cam a wee bit tight? - 07/22/13 03:57 PM

its hard too say witch bearing is snug,ive hadem like that before and just ran it no probs.but without actually feeling it myself its a tough call.you could take a fine brake hone and just turn it by hand once you find the tight bearing.
Posted By: Cab_Burge

Re: New cam a wee bit tight? - 07/22/13 07:28 PM

BB Mopar are famous for having the cam tunnel not machined to the proper size from the factory I now install one bearing at a time and test fit the cam, if it is good I install the next one and so on unless I find a tight one, if and when( 3 out of 10 blocks will have a tight one ) I find a tight one I use a bearing knife to scrape the high spots off, they will shine at you until the cam spins freely by hand like your trying to do I don't like using any abrassive stones or papers that may leave some abrrassive material in the soft cam bearings One of the machine shops I use to use in Orange County, CA would use a brake or small cylinder hone on the bad cam tunnel holes to bring them up to the proper sizes and I.D. He would then installed the new cam bearings, I never had a problem with them done that way
Posted By: Sixgun

Re: New cam a wee bit tight? - 07/22/13 07:53 PM

Got a machinist coming if I wait that long...I might LIGHTLY and Carefully polish the #1 cam journal itself (right terminology?cam itself not the bearing...)and see if she frees up.Machinist says it is probably OK as -is (without seeing it personally yet), but I could try a light polish,as above, he does not think it will help or hurt,but OK to try.
Posted By: Von

Re: New cam a wee bit tight? - 07/22/13 08:15 PM

Chuck it in a crank polisher and lightly polish the offending journal. Quick and easy.
Posted By: Sixgun

Re: New cam a wee bit tight? - 07/22/13 09:14 PM

Might take it to the lathe in town if need be.
Von, I have same car as you in a Satellite clone,
any good pics or video of your runs?Or just the car?
Bear
Posted By: BigBlockMopar

Re: New cam a wee bit tight? - 07/22/13 09:15 PM

Most cams are tight in new bearings.
Like Cab mentioned, rotate the cam a few times in the bearings with a wrench.
Take it out, look at the bearings which have shiney areas on them. Polish those areas.
Posted By: Lefty

Re: New cam a wee bit tight? - 07/22/13 10:04 PM

Quote:

BB Mopar are famous for having the cam tunnel not machined to the proper size from the factory I now install one bearing at a time and test fit the cam, if it is good I install the next one and so on unless I find a tight one, if and when( 3 out of 10 blocks will have a tight one ) I find a tight one I use a bearing knife to scrape the high spots off, they will shine at you until the cam spins freely by hand like your trying to do I don't like using any abrassive stones or papers that may leave some abrrassive material in the soft cam bearings One of the machine shops I use to use in Orange County, CA would use a brake or small cylinder hone on the bad cam tunnel holes to bring them up to the proper sizes and I.D. He would then installed the new cam bearings, I never had a problem with them done that way



Slick tricks I'm keeping this post for future reference. Thanks Cab.
Posted By: BigBlockMopar

Re: New cam a wee bit tight? - 07/22/13 11:00 PM

For a quick & dirty 'scrape' of the bearings, I've modified an old cam by cutting slanted grooves in all the bearingjournals.
The grooves acts as a scraper when rotated in the bores.
Posted By: JohnRR

Re: New cam a wee bit tight? - 07/22/13 11:24 PM

Quote:

Got a machinist coming if I wait that long...I might LIGHTLY and Carefully polish the #1 cam journal itself (right terminology?cam itself not the bearing...)and see if she frees up.Machinist says it is probably OK as -is (without seeing it personally yet), but I could try a light polish,as above, he does not think it will help or hurt,but OK to try.



Polishing the journal or turning down the journal isn't the right way to do it .

You think it's the front journal but it may not be take the cam and put it in backwards and see how it fits into the #1 journal ? Can you do the same with #5 ?

The way cab describes above, do one at a time, is the way to do it that way you find out which is the offending bearing.

How did you install the #1 bearing , from the front or from the rear ?
Posted By: John_Kunkel

Re: New cam a wee bit tight? - 07/22/13 11:48 PM


Run it as is, don't mess with it. I'd be tickled to death to get one to turn with 35-40 inch pounds.
Posted By: Sixgun

Re: New cam a wee bit tight? - 07/23/13 03:02 AM



Polishing the journal or turning down the journal isn't the right way to do it .

You think it's the front journal but it may not be take the cam and put it in backwards and see how it fits into the #1 journal ? Can you do the same with #5 ?

The way cab describes above, do one at a time, is the way to do it that way you find out which is the offending bearing.

How did you install the #1 bearing , from the front or from the rear ?


Installed from the front with a custom mandrel, as the rest looked OK, the #1 was showing copper.
No room to put the cam in backwards, as the darned hood latch support is right there in the way.I can squeak it in at a slight angle to install normally.
Regards,
Bear
Posted By: Sixgun

Re: New cam a wee bit tight? - 07/23/13 03:08 AM

Quote:


Run it as is, don't mess with it. I'd be tickled to death to get one to turn with 35-40 inch pounds.


JohnK,really?So that isn't an issue? I was thinking myself (dangerous, that...)that this IS after all the grooved one, and as such will have 360' oil all the time, will probably clearance itself pretty quick?I like the idea of as much bearing material as possible ie not changing the fit if I don't have to...
Posted By: ProSport

Re: New cam a wee bit tight? - 07/23/13 03:22 AM

I just ran my whole short block back to the shop last week due to the same problem. I wanted them to do it so it was done right, especially if they have to take it apart. My cam wouldn't even go in.
Posted By: Sixgun

Re: New cam a wee bit tight? - 07/23/13 04:49 PM

We found the middle cam bearing to have horizontally opposed 'pinch points' showing up as shiny spots.Appear to have been there a long time.
Must be either an out of round cam bearing saddle,
(core shift) or a non concentric cam bearing,either way its gotta stay in there.As the pan is being changed,considering stuffing a rag under the tunnel,using a ho made dowel or PVC with 400 grit secured to it to attempt to polish the high spots,then flush well with penetrant;
or leave it alone and run as-is.
Thinking.
Posted By: JohnRR

Re: New cam a wee bit tight? - 07/23/13 05:27 PM

Quote:

Quote:



How did you install the #1 bearing , from the front or from the rear ?


Installed from the front with a custom mandrel, as the rest looked OK, the #1 was showing copper.
No room to put the cam in backwards, as the darned hood latch support is right there in the way.I can squeak it in at a slight angle to install normally.
Regards,
Bear



Putting in that bearing from the front is what usually causes the issue you have with it , it got cocked when putting it in more than likely.

What are you doing with the old cam? You could cut off the length of it you need to so you can put in the front journal and use it to adjust the bearing size by rotating it in an elliptical pattern.

I'll bet those shiney spots are from the old cam FITTING itself to the bearing hole.
Posted By: Sixgun

Re: New cam a wee bit tight? - 07/24/13 04:30 AM

JohnRR, my old friend,
The front bearing tool was a 3 step aluminum plug that was also the removal tool.You can actually see the edge of the bearing is true with the edge of the cast iron bore.
The old cam was given away to a fellow that does not mind trying to polish the scorched lobe tips :-)
for his tow truck???
Pretty sure this was a pre existing condition, and I feel it in my bones that this will remedy it, at least matching the quality of the fix to the quality of the rest of the "build"
I may be wrong, but I'm going to think a little more, then take action.Not arguing with your logic, as I usually agree with it.I'm just the one looking at it here onsite.
Thanks!
Bear
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