Cam bearing orientation.....

[RedBird]

i have a serious question here guys. I took my block in to be hot tanked, and have new cam bearings put in. well, i get it back, and it's barely cleaned, and the bearings are crooked from what they are stock. he said he put the new ones in the same as the old ones were. well the old ones were partially spun..... My question is, does the orientation of those oil holes matter? he said that the oil groove under the bearing goes all the way around, so i wouldn't think it would matter much......right? or was he lying?

Also, he said his dip is used to do aluminum too, which is why it didn't strip off the black paint...... but i think he's trying to bullshit me, b/c there was part of a sticker that was on the block.......well, still there. wtf is going on?

[sprucegagt]

Sounds like a cheap machine shop did some lousy work. Your block should be completely bare. No paint or anything left on it. As for the cam bearings, the location of the oil hole is CRITICAL to getting oil to the cam. If the oil holes in the bearing are not lined up with the holes in the block then the cam would not get any oil to it.

[RedBird]

ok, so, new question. Since these bearings are brand new still.... would it be possible to remove them and have someone competent put them in correctly, or are they junk once they are installed and removed?

[sil]

i wouldnt trust that shop worth shit, not even to bring it back to get it re done

im an ass so id prolly go the bbb route, get another shop to do it whilst having them pay for it

(why should you have to pay twice )?

[RedBird]

yeah, that was what i was thinking. But i called him and he's so absolutely sure that it doesn't matter how they are in there, and he's saying oh yeah, regular hot tanking usually doesn't take all the paint and stuff off, that's only acid dipping....... he's a stubborn bastard. i dont plan on having them do any more work on this motor, or any other if i can help it..... And if he doesn't refund me i'm gonna make him sure that i'm gonna bad mouth his shop for the rest of my life. He'd be better off giving me my money back than losing all that business.....

Oh hey, what IS the proper positioning. The oil holes need to be straight down, right? and what about the bearings with 2 holes? or do they all have 2?

One more thing. Where are the oil holes on the block for the cam bearings?

[bracketracer]

I can't vouch for the cam bearing situation, but I can speak for the hot-tanking. My block was hot-tanked and it did a great job of removing grease, oil, loose paint, etc, but it does not take it down to bare metal. Alot of the block still has original engine enamel on it, but only the areas where the paint is still adhering to the block well. To take it down to bare metal would have required quite a bit of wire brushing or blasting of some type. I didn't expect that for how little I paid for hot tanking. My engine builder is quite knowledgable and reputable, so I know this wasn't some con or hack-job.

[RedBird]

Alright then, i guess i might not worry about the hot tanking so much then..... but the crooked am bearings still bother me. I can't find any pics of how the bearings are supposed to sit stock, even though i know there should be some.........Anyone know? Got pics? Anything?

[Superdave]

found a pic for ya...

this is Jason's 3400

[sharkey]

hot tanking a block should strip it down to bare metal. you also can not hot tank aluminum, the solution used is highly caustic and will eat the aluminum. he likley put it in a wash tank with water and a soap solution. many shops have this for cleaning aluminum parts, it does an alright job but wont remove everything.

as for cam bearings, there is indead an oil groove under the bearing so positioning of the bearing does not matter. still, any good machinist will align the oil holes in the bearing to the feed hole in the block.

[geoffinbc]

I agree. The blocks for sure have a groove ALL around the cam bearing. The groove carries oil from the cam bearings to the mains.

But he still should have aligned the holes. The Chevy Power manual says to position the oil feed hole between 4 and 5 o clock when viewing from the front.

[smilinguy99]

The bearings spun for a reason. Did the intake gaskets leak anti-freeze into the oil? Have you already found the cause?

It might be interesting to remove the bearings for no other reason than to see what, if any, damage the old bearings did to the block when they spun.

sg99

[gectek]

yah after you remove them they are trash really, and the groove does go all the way around, but the alignment is recommended to help in startup and breaking in the cam, what bearings did u use

[Superdave]

The cam bearings spun only after a rod bearing spun. It was my 3400 from last year...

no intake leaks as the gaskets only had a few K miles on them.

betterthanyou, you say between 4 and 5 o'clock which is where they were placed from the shop... Altho they're at 6 o'clock from the factory...

[gectek]

6 oclock central or eastern...

[3400-95-Modified]

Its pacific time...

But I would agree with the statement that the block may have damage done to it.. It depends on how bad the cam bearing spun but typically when those let go they will rip the cam journals to hell and make future bearings not fit so well... I would look to see if there is any damage and then try to get someone with half a brain to install new bearings.

I also had a block hot tanked... it came back bare, and there was rust and whatnot on it when I dropped it off.