Re: Camshaft too tight.
[Re: royt440]
#348612
06/16/09 01:03 AM
06/16/09 01:03 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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a brake hone w fine stones for cam journals 1,2,4,5 & fab an extension for your hone to reach #3
live every 24 hour block of time like it's your last day on earth
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Re: Camshaft too tight.
[Re: goldmember]
#348614
06/16/09 01:41 AM
06/16/09 01:41 AM
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Joined: Oct 2007
Posts: 3,911 Oregon
hooziewhatsit
master
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master
Joined: Oct 2007
Posts: 3,911
Oregon
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Is this caused by having one (or more) of the bearings slightly out of alignment when it was installed? So in effect, it's squeezing the cam?
If so, could it be fixed by replacing the (errant) bearings again, and hoping they go in correctly?
(Curious, so I'll know what to do if I ever see it in the future)
-Dave
If you ever find yourself in a fair fight, your tactics suck.
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Re: Camshaft too tight.
[Re: hooziewhatsit]
#348615
06/16/09 01:52 AM
06/16/09 01:52 AM
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Joined: Feb 2004
Posts: 4,501 Gainesville,FL
goldmember
master
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master
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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Could be the bearing bores are not aligned,the bore(s) are not correct diameter,bearing out of spec,etc. You could replace a single bearing,may not fix the problem. You can install the cam,rotate the cam,remove the cam and inspect the bearings. You will see the problem area. If you don't feel confortable removing the tight spot(s) just have your shop do it.
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Re: Camshaft too tight.
[Re: royt440]
#348617
06/16/09 07:10 AM
06/16/09 07:10 AM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Do not use a hone or paper, or any abrasive on the bearings... As wa said, the technique is to use a sharp blade to scrape away the high spots that make the cam hard to turn. That's it. Not hog the hole out until it fits. By installing the cam with light oil (I use WD40) and turning it you will see the tight spots as shiney areas. Then I use a single edge razor blade (KD Tools I think used to make a fancy cam bearing scraper tool) to scrape the high sprots and remove a very thin layer just from that spot(s). When I can tunr the cam by hand with two fingers (little effort) it's done.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Camshaft too tight.
[Re: moper]
#348618
06/16/09 09:06 AM
06/16/09 09:06 AM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Before you do anything with the cam bearings, put the cam in some V blocks and check it for straightness. Shouldn't be out more tham .003". If your machine shop is on the ball they would have a mock-up cam that they ran through the bearings to make sure you didn't have this problem.
Fastest 300
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Re: Camshaft too tight.
[Re: royt440]
#348619
06/16/09 09:45 AM
06/16/09 09:45 AM
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Joined: Oct 2005
Posts: 8,926 Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,926
Ontario, Canada
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core shift, cocked bearings, bent cam ... all BS !! This is one of the most common big block problems and for the REAL lowdown read this: http://www.musclemotorsracing.com/muscle-mike-blogShort of $1000 fix, I'd be going in to the tight bearing(s) with a hone and hoping to hell they don't need much taken off.
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Re: Camshaft too tight.
[Re: Crizila]
#348623
06/16/09 01:56 PM
06/16/09 01:56 PM
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Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
If your machine shop is on the ball they would have a mock-up cam that they ran through the bearings to make sure you didn't have this problem.
Amen to that!
How does something like that get out the door unchecked?
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Re: Camshaft too tight. - the REAL story...
[Re: Rick_Ehrenberg]
#348624
06/16/09 02:53 PM
06/16/09 02:53 PM
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Joined: Dec 2003
Posts: 5,314 Carstairs, Alberta, Canada
dave571
master
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master
Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
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Quote:
This will blow your mind but it is FACT.
The factory always did a halfass job boring the cam tunnel. They didn't really care...because the OEM cam bearings were WAY undersized, they then line-bored (precision) the BEARINGS.
Now you know why all the old MP manuals suggest not changing the cam bearings unless absolutely necessary!
About all you can do is use a bearing knife or an old cam with sharp grooves to act as a reamer.
Rick
Yup.
Most machine shops will clearance them with a cam that has been cut for this.
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Re: Camshaft too tight. - the REAL story...
[Re: dave571]
#348625
06/16/09 03:00 PM
06/16/09 03:00 PM
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Joined: Oct 2003
Posts: 3,698 NE Oklahoma
Von
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master
Joined: Oct 2003
Posts: 3,698
NE Oklahoma
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I have a 72 440 block that is a total mess as far as the cam bearings go. When I first got the car the block was in (1988) I tried to swap cams. 2 of the cam bearings were spun. Finally got 2 bearings back in the dang thing...after a few stitches due to cutting a finger on the bearings. I had to pound the cam into the last set of bearings. It was so tight the motor would barely turn over. Once it did light, it clearanced itself pretty quickly. When I tore that motor down and re did it, had new bearings put in. Same thing as before, cam was way tight. We screwed a grade 8 bolt in the end of the cam, chucked the bolt in a drill and tried to loosen it up. Bad idea, broke the bolt off in the cam. Had to take a stock cam and groove it to ream the bearings. No problems after that, oil pressure was rock solid. After 1k miles and a couple dozen passes, pulled the motor down, everything looked fine. Last time around with this block, took it to a machine shop and asked if they correct the journals. I was told no problem, he could use the line hone to fix the journals. Well, he didnt. He scraped the bearings to fit my cam. No biggie, but I paid to have the journals honed, not the bearings.
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Camshaft too tight. - the REAL story...
[Re: Von]
#348627
06/16/09 03:20 PM
06/16/09 03:20 PM
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Joined: Jul 2008
Posts: 30,537 Florida STAYcation
dOc !
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,537
Florida STAYcation
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Quote:
It was so tight the motor would barely turn over.
HOW did you get the cam in-there to begin with ? ...
ALL THIS here on this topic confirms what I have thought for years. NOT to "boil" a block(thus ruining the cam bearings) .. to clean-it myself .. or - at the most - to whirly-bird it.
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