New cam and bearings hard to turn

[Davea Lux]

Back when dinosaurs ruled the earth and cam bearings were poured babbitt on many engines, a reamer would be used to semi finish the bearings until the cam could be inserted. If it turned too rough or too tight, a hardwood block with a mallet would be used to strike the cam and flatten out the high spots. Would not want to try that with a modern brittle camshaft.

I did notice some misalignment on #5:

View attachment 381151

That needs to be fixed.

Dave

 

[Jeremiah]

My machinist had me measure the cam bores and remove material from the outside of the cam bearings for the tight journals . That is how I do them now. All you can do once they are in stalled is scrape away carefully.

 

[moper]

Good work. I'm not a fan of "honing" with an abrasive of any kind. The abrasive that usually separates during the work can get into the oiling system after the filter and before the bearings because right behind that hole that feeds the cam journal, is the intersection where oil turns and goes to the main and rod bearings. Not a fatal deal but I never liked the idea.
I wouldn't sweat the slight misalignment on #5. Now that the cam can turn by hand easy, that "partial hole" will provide plenty of oil for that bearing.

 

[Samplingman]

Good work. I'm not a fan of "honing" with an abrasive of any kind. The abrasive that usually separates during the work can get into the oiling system after the filter and before the bearings because right behind that hole that feeds the cam journal, is the intersection where oil turns and goes to the main and rod bearings. Not a fatal deal but I never liked the idea.
I wouldn't sweat the slight misalignment on #5. Now that the cam can turn by hand easy, that "partial hole" will provide plenty of oil for that bearing.

Thanks, I was starting to lose sleep over that. I thought about the sediment from the abrasive and flushed each oil passage a number of times by turning the motor over and letting the oil drain out. That bearing material is so soft, I imagine a lot of material gets into the system during break-in.

 

[moper]

Yeah it’s not the bearing material. It’s the abrasive from whatever’s being used. Sandpaper and scotchbrite shed a lot. emory not as much but it still does. And while the bearing material won’t harm anything major, the grit hopefully embeds and you’re good. If not it can score bearings and journals.

 

[Ripinator]

Thanks again everyone for all the help. We popped the rear cap and could see right away where the high spot was just from rotating the cam a few times with the breaker bar. I didn’t need to cut the old cam, I used 600 grit soaked in oil to hone the bearing. We were able to see high spots on the other bearings and repeated the process until I was able to spin the cam with two fingers. As a precaution I used a magnet to pick up any stray flakes and repeatedly squirted light motor oil to flush any debris. @moper was right, the chain fit when everything was in the right place, although there is absolutely no slack. I was able to turn the whole rotating assembly, no binding or scraping sounds.
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James: I'm so glad to hear you were able to fix your cam problem. Good luck on the rest of the engine assembly, and hopefully, there won't be any other issues.

 

[Samplingman]

Thanks man! My son and I finished up to the heads tonight. So far so good, but I probably won’t hear it run for another month or two. I do have a bit of painting to do....

 

[Ripinator]

Thanks man! My son and I finished up to the heads tonight. So far so good, but I probably won’t hear it run for another month or two. I do have a bit of painting to do....

View attachment 381399

James: One more thing: Make sure you use a good break-in oil when you initially fire up the engine. I used this stuff when I started my rebuilt 440:

COMP Cams Engine Break-In Oil 1591

And I see - like me - you have one of those three-wheel tip-over engine stands. Be damned careful when you roll that thing around. . .

 

[Samplingman]

Thanks Rip, the machinist gave me something, I’ll have to dig it out. Yeah, the goal is to get it off that stand as soon as possible! I’ve gotten used to it and it rolls and rotates real easy, but now that the heads are on, it’s flexing more. Torquing last night was making me nervous while pushing down at 70 foot pounds. I’m debating about putting the intake on while on the stand. This has been on loan from a friend all these years, and he had rebuilt everything, small block, big block and a slant 6 without issue, so I’m hopeful it will withstand the added weight.

 

[Ripinator]

Thanks Rip, the machinist gave me something, I’ll have to dig it out. Yeah, the goal is to get it off that stand as soon as possible! I’ve gotten used to it and it rolls and rotates real easy, but now that the heads are on, it’s flexing more. Torquing last night was making me nervous while pushing down at 70 foot pounds. I’m debating about putting the intake on while on the stand. This has been on loan from a friend all these years, and he had rebuilt everything, small block, big block and a slant 6 without issue, so I’m hopeful it will withstand the added weight.

Yeah. That stand is OK, if yer not gonna move it. I have my old complete 383 bolted to mine, and its real tipsy.

 

[Trace 300 Hurst]

View attachment 381399

I see a BFH on the floor!

 

[3175375]

I see a BFH on the floor!

Rubber mallet, I believe.

 

[Samplingman]

I see a BFH on the floor!

Yep, better on the floor then in the oil pan, LOL!

I did have a bit of a panic last night cleaning up when I couldn’t find a 9/16 socket. Found it at the end of an extension in the tool box.

 

[Trace 300 Hurst]

I have a surgeon pal.....he says he has that heart-stopping panic rather often when he's "cleaning up".

 

[Samplingman]

I have a surgeon pal.....he says he has that heart-stopping panic rather often when he's "cleaning up".

Yikes!!

 

[Trace 300 Hurst]

At least it's not a BFH!

 

[twostick]

Make sure you use lots of cam lube on the cam and bottoms of the lifters when you do the final cam assembly and verify that ALL the lifters spin. The pushrods should all spin like they are gear driven. Don't turn the engine over more than it takes to verify lifter rotation. One revolution or less will tell the tale.

If any don't spin or don't spin consistently with the others, do not proceed until you find out why. 90+% of cam failures can be traced back to this and the damage is done the moment it fires.

Kevin

 

[Samplingman]

Make sure you use lots of cam lube on the cam and bottoms of the lifters when you do the final cam assembly and verify that ALL the lifters spin. The pushrods should all spin like they are gear driven. Don't turn the engine over more than it takes to verify lifter rotation. One revolution or less will tell the tale.

If any don't spin or don't spin consistently with the others, do not proceed until you find out why. 90+% of cam failures can be traced back to this and the damage is done the moment it fires.

Kevin

Ok, that's good to know, that wasn't mentioned in the book. I did put lots of the cam lube I got from the machinist, but with all the other oil I've squirted on this motor I'll be doing it again.

 

[jbooth35]

When I rebuilt my slant six the new cam was tight. The machinist took my old cam and cut a triangular notch in the lobes. He then turned that cam and used it shaved the bearing. We put the new cam back in and it turned freely. First time I had seen that done but it seemed to work. I’m not saying that was the right thing to do but the machinist didn’t even hesitate.

 

[3175375]

...and cut a triangular notch in the lobes.

Did you mean the area where it mates with the bearings? I don’t understand why he would not have the lobes - that wouldn’t do anything regarding the bearings.