aaronk785
Well-Known Member
Looks like normal start up wear to me.
Cam bearing issue
- Thread starter PredaFran
- Start date
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MOPAROFFICIAL
Oogliboogli
Cockeyed bearings, distorted cam tunnel bores, bearing or cam journal on the high low side tolerance or micro debris...dry start.... all potential causes.
Scrapings good, even scotch bright dish pad wiped over a time or two where its tight/leaving dark marks of contact.
Cases of older engines where they fall apart can be do to the corrosive agents/contaminants in infrequently changed oil. Blow by makes the oil darken quick with an older engine, so more frequent oil changes become mandatory or this will hurt the factory's lead bearings. Other times where someone decided to put a cam in and some heavier springs...on say..some 40yr old contaminated bearings.. they can too fall apart.
Scrapings good, even scotch bright dish pad wiped over a time or two where its tight/leaving dark marks of contact.
Cases of older engines where they fall apart can be do to the corrosive agents/contaminants in infrequently changed oil. Blow by makes the oil darken quick with an older engine, so more frequent oil changes become mandatory or this will hurt the factory's lead bearings. Other times where someone decided to put a cam in and some heavier springs...on say..some 40yr old contaminated bearings.. they can too fall apart.
James Clews
Well-Known Member
When I assembled my 318 I had a tight cam bearing and as I was not as smart as some of you guys , didn't think to cut my old cam up. I measured all the thinks I had and presto my aluminum Jack handle was the correct size. I wraped some wet and dry around it and using plenty of wd40 reamed it out.It worked okay.
I have been following this thread with great interest, and have had some issues with camshaft installs myself. Generally only one bearing would give me fits and usually remedied with a small wipe or two with a scotch pad. I am in the process in rebuilding a Kent cross-flow engine and they suggested using fine emery cloth to clean the cam journals. I have never heard of this before, is it done to remove the polished glaze from the journal?
Other web sites also mention it as well, using 600 grit paper and oil on a lathe. Maybe here, and we are only taking cam journals, a dull or hazy surface on the journals would help to retain and carry the oil then a journal that is highly polished....
The pictures the op showed bearings wear on the bottom which pretty much normal as we all know the weight of things are on top. All the bearings look the same, hard to believe anything is bent here. I use assembly grease in these areas, oil doesn't really like to stay put for to long.
Other web sites also mention it as well, using 600 grit paper and oil on a lathe. Maybe here, and we are only taking cam journals, a dull or hazy surface on the journals would help to retain and carry the oil then a journal that is highly polished....
The pictures the op showed bearings wear on the bottom which pretty much normal as we all know the weight of things are on top. All the bearings look the same, hard to believe anything is bent here. I use assembly grease in these areas, oil doesn't really like to stay put for to long.
6PakBee
Well-Known Member
Whoever took that picture should be shot. That is a great way to have the abrasive strip get caught by the shaft and pull your hands into the shaft. A paint stir stick with the abrasive fastened to it is a much better approach.
All of the lathe work I have done and still do never had that problem. The spindle speed does not have to be a high RPM, and taking care and experience comes into play here. But lathe safety is not the issue here, is it? But thanks for your suggestion.
6PakBee
Well-Known Member
Some people work under their cars suspended on nothing but a bumper jack. I suppose taking care and experience comes into play there also.
Really don't you have anything better to do? I am helping this thread out with information and suggestions, not a derailment.
Maybe we should discuss his dirty thumbnail too? Good lord.....
6PakBee
Well-Known Member
A safety hazard is a safety hazard. Now you two can yuk it up all you want but the fact remains that is not only NOT a recommended method but an unsafe one. Period.
Outasite
Well-Known Member
I have a piece of brass bar and a used cam,after I install the first two new bearings I slide in the “test cam” if it spins easy then the third, and so on.If one seems tighter I use the brass bar and TAP
the cam to burnish the fit.Hardly ever will they not need some help.
the cam to burnish the fit.Hardly ever will they not need some help.
Pop In new bearings. Lube up cam bearings and cam with Lucas Oil engine assembly lube. (Like STP)
Slowly wind in the cam and keep cleaning off the milky gray bearing residue, keeping it lubed as you go, until you finally have a smooth turning, easy turning final fit with the cam.
Used cams works good with or without the relief cuts.
The better job you do installing the cam bearings in straight and true, the easier it is to fit the cam.
Have had good luck installing the cam bearings into the block with a little Vaseline on them, instead of them going in dry.
☆☆☆☆☆
Slowly wind in the cam and keep cleaning off the milky gray bearing residue, keeping it lubed as you go, until you finally have a smooth turning, easy turning final fit with the cam.
Used cams works good with or without the relief cuts.
The better job you do installing the cam bearings in straight and true, the easier it is to fit the cam.
Have had good luck installing the cam bearings into the block with a little Vaseline on them, instead of them going in dry.
☆☆☆☆☆
Outasite
Well-Known Member
Poorly fitted or worn cam bearings will have a huge effect on oil pressure.I restrict the flow to them.
Dave999
Well-Known Member
i'd clean em up with emery or 1200 wet n dry.. used wet wd40 diesel kero or similar
clean them and the cam off in brake cleaner
check the oil holes all align
when spotlessly clean stick it in with wd40 and spin it
if it spins reasonably well.. all good.
blow dry, assembly lube to save it when you are cold cranking to start, job done ... if this method works on crank journals that you nick and main bearings that you ding by dropping stuff... (which it does) it will work here.
run a short break in again and never look at them until the next rebuild.....
if the block or bore was misaligned to any great extent you would not have been able to fit the cam
if the bearings were so undersised by the action of fitting you wouln't have been able to fit the cam
your cam fits.....Nice
if you had tried the bearings on the cam before fitting they would have been too big.
keep in mind if you didn't see metalic particles in the oil of a new engine after break in i'd be a bit suss.... the final "machining" of everything occurs during break in... the last polish of every surface is basically happening. break in oil is kinda crap as a general every day drving oil. it deliberatly and by design, doesn't have the lubicity of the stuff you run from the end of break in onwards, its good enough to keep the parts apart once running, but crap enough to allow rings to bed in properly and allow all the tiny bits that needs shaving off everything to shave off. most of the metal bits probably came from the thrust face of the main bearing that provides the crankshaft thrust...they usually have more FACE than the crank does and you always get a few bits n bobs off there, espeically on a manual if you start it....with you foot on the clutch ... naughty...
.
Dave
clean them and the cam off in brake cleaner
check the oil holes all align
when spotlessly clean stick it in with wd40 and spin it
if it spins reasonably well.. all good.
blow dry, assembly lube to save it when you are cold cranking to start, job done ... if this method works on crank journals that you nick and main bearings that you ding by dropping stuff... (which it does) it will work here.
run a short break in again and never look at them until the next rebuild.....
if the block or bore was misaligned to any great extent you would not have been able to fit the cam
if the bearings were so undersised by the action of fitting you wouln't have been able to fit the cam
your cam fits.....Nice
if you had tried the bearings on the cam before fitting they would have been too big.
keep in mind if you didn't see metalic particles in the oil of a new engine after break in i'd be a bit suss.... the final "machining" of everything occurs during break in... the last polish of every surface is basically happening. break in oil is kinda crap as a general every day drving oil. it deliberatly and by design, doesn't have the lubicity of the stuff you run from the end of break in onwards, its good enough to keep the parts apart once running, but crap enough to allow rings to bed in properly and allow all the tiny bits that needs shaving off everything to shave off. most of the metal bits probably came from the thrust face of the main bearing that provides the crankshaft thrust...they usually have more FACE than the crank does and you always get a few bits n bobs off there, espeically on a manual if you start it....with you foot on the clutch ... naughty...
.Dave
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