well shoot..

[QBuff02]

was in the process of performing a cam swap on the ol' 454 and got the balancer and timing cover off last night, went to work pulling the rockers, push rods, lifters and cam. Everything went fairly smooth, but I had long suspected an issue of some kind with the gear drive (just didn't sound "right") and found that one of the gears is loose on the pin and you can see where it was eating into the bar that holds the idler gears together. No big deal right? went ahead and pulled the gears and slid the cam out of the engine and that's when I found pretty good wear on the front cam bearing and what appears to be a crack about halfway through the front bearing itself. greeeeat! So now I'm at sort of an impasse as to the direction to go. Especially since to anyone that's followed along with this truck.. the internals of the engine have been somewhat of a mystery. along the lines of when I bought it "it's got this, it's got that, it's a good 4 bolt block with the steel crank and good parts. yadayadayada..." But the deeper I dig the more I find that I was actually told some truth on a purchase for once! Lol The cam was an XE262H from Comp which is supposed to make serious torque for pulling. (not big enough for me! Lol) However, it does have a good set of big ovals with some work already done to them and now I know after further disassembly.. It really is the good 4 bolt block with steel crank, and upon some deeper investigation it also has a set of the 7/16" rod bolt version "dot" rods. Which is a bonus! So now, what was going to be a 2 weekend swap of the cam and intake to free up some ponies, and have it driving for the 4th of July (because nothing says America like watching them fireworks from the bed of an old Chevy!) is probably going to turn into a 2 month long rebuild, oooorrr.. in interest of time and wanting to drive it this year, and possibly in 2 and a half weeks, a quick tear down, cleaning, check over and freshening up with new bearings and rings.. And at that point I could set the heads up to be dead on for the cam I want. I'm kind of on the fence, because once it's apart that far, generally it would be wise to just go all the way! Decisions decisions.. Any who, here's a little picture food for you guys while I ponder the afternoon away before stopping at the engine builder to discuss further later!

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[84 M1008]

Question is, why did the cam bearing crack? Is this common?

 

[shiftpro]

Maybe the cracked bearing isn't so much of an issue...?? For a while anyway perhaps?

 

[84 M1008]

Any bearing failure is a big problem. Lucky it was found in time before the engine came apart.

 

[theblindchicken]

Easily need all new cam bearings and new cam. Timing gears are cheap if you don't want to get an all gear drive again.

I say tear into it and at least check everything. Sure, it'll take more time, but better to tear into it now than put some new parts into it and have a failure deeper in that could have been avoided.

 

[QBuff02]

Question is, why did the cam bearing crack? Is this common?

Talked to my engine guy a little bit ago, and he said it's a pretty UNcommon thing, but he did say if when the previous owner installed the aftermarket cover after the original setup and didn't reset the tolerances on the gear drive and the cam end play, that it, coupled with the higher spring loads on the cam from the stiffer valve springs and the fact that gear drives have pretty much ZERO give to them, he could see it stress and wear a bearing excessively but that a cracked cam bearing is a rare thing, especially in a big block. No matter what route I go, it's highly unlikely to have a gear drive put back in it, although I dig the sound of them, I'm a bigger fan of good double roller timing set ups and a little bit of "give". Unless I'm persuaded otherwise! Lol

 

[QBuff02]

Easily need all new cam bearings and new cam. Timing gears are cheap if you don't want to get an all gear drive again.

I say tear into it and at least check everything. Sure, it'll take more time, but better to tear into it now than put some new parts into it and have a failure deeper in that could have been avoided.

And I'd hate to grenade a good engine because I was cutting corners!

 

[84 M1008]

I was thinking that same thing. The roller chain is the way to go. You're really at the mercy of the person that built the engine. At least when you put it all together you'll know what you have.

 

[Zoomalot]

VERY unusual to see a cracked cam bearing!!!
You got her apart!
Build it right!!!!!!
You won't regret it, in the long run
#9 wire is not what this forum is about.(anyone can cut wire)

 

[QBuff02]

well, it's in pieces! Lol Dropped the parts off at the machine shop last night for a clean up and inspection of critical components, cylinder honing, all new cam bearings, freeze plugs, etc. And checking the rotating assembly and heads, hopefully have some good news and parts back in about a week!

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