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1990 trooper 2, 76 Datsun 620
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Discussion Starter · #61 ·
I was told that the bearings I brought didn’t fit and were destroyed upon removal, the gasket issue, well they had the wrong part number to begin with and were confused on what to get. The performance manual on these motors lists the small block cam bearing as a performance option, they do fit, gm says they fit. Most places don’t really work with this v6 so it’s no surprise.
I was going to let the bearing issue slide but now I’m not, seeing how rough they look, I’m not running a new cam on those! But if I want it done right I probably should just do it myself.
I’ll have to call them up on Monday and ask wtf happened.
 

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1990 trooper 2, 76 Datsun 620
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Discussion Starter · #62 ·
What I really should have done was just have them do the cleaning and machining, and measure for the main and rod bearings, I didn’t know how exactly to do that.
 

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I'd be a whole lot more than disappointed! I'd be having some very stern words with the manager of the machine shop. Any shop that can't handle installing a set of Chevy cam bearings shouldn't be working on engines at all!

And BTW, it's been established for Eons that small block Chev V8 cam bearings can be used in the 60-degree V6.

I'll quote you some good info from the GM 60-degree V6 "bible",

How to Rebuild Your GM V-6 60 Degree Engine by Tom Currao:

Aside from excessive wear, the cam bearings will need to be replaced if you have the block hot-tanked, since hot-tanking destroys them. Replacing the bearings requires special tools and expertise, so save yourself time and money and have your machine shop do it. The shop will use a long rod with a plate screwed onto one end to drive out the old bearings and install new ones. As the new bearings are installed, attention is paid to the alignment of the bearing lube holes with the groove that runs around the perimeter of each cam bearings bore in the block.

<my boldface>

In some instances, this alignment is so far off that the shop has to install the wider cam bearings from a 350ci small-block Chevy, because these bearings are wider than the stock bearings and allow the shop to compensate for misalignment. However, because of the additional width, these bearings have to be precisely positioned to avoid contact with the cam lobes. Unless you're confident you can do this work yourself, it's better left to the pros.

Also, keep in mind that a new type of cam bearings is being used in later-model engines. Instead of the traditional babbit lining, the bearings have a very hard wear surface, similar to that of oilite. These bearings should offer longer service life along with decreased oil pressure loss due to wear. So if you're in the market for cam bearings, you should consider using this later-style design.


Granted this is from 1994, the use of aluminum-clad bearings is quite common nowadays and you should be using that type of bearing for cam, mains, and rods.

IDK if you sent the crankshaft off to the machine shop, but typically they'd use a micrometer set to measure the crank for worn journals, and also put the crank on a set of V-Blocks and do a runout with a dial indicator. If the crankshaft is still Standard, and the journals are nice n' smooth or clean up with a light polish to specifications, then all you need is a set of Standard bearings.

If the crank journals are in poor condition, then they'd be telling you how much undersize all the journals will have to be ground. Or you can just throw the old crankshaft at them as a core, and for a nominal fee they'll give you back a nice reground crank/bearing kit with all the appropriate-sized bearings included.

IDK about you, but I wouldn't have so much faith in the machine shop. I picked and chose all of my parts so I could control the quality.

When you assemble the crank into the block, you still need to use some Plasti-Gage Green to check oil clearances on the mains and rods. I'm assuming you don't have access to a micrometer set.

Another thing comes to mind, what are you doing with your rods? I had mine reconditioned and the machine shop pressed them onto new Sealed Power coated pistons. Not cheap but you know the rods are straight, and the big & little ends are the correct i.d.

I looked up a '94 Camaro 3400 and the main/rod bearings you'd want are the "A-Series". Rockauto is offering those in a Sealed Power and Mahle flavor. Both are quality brands. Enginetech also shows an aluminum-silicone bearing; they talk about that in the detailed description. These bearings will wear much better than babbit and they're far more resistant to corrosion from inadvertent coolant in the oil.

Here are some Sealed Power Bi-Metal aluminum cam bearings for a Chevy V8, I'm assuming something like those would be what you'd want:


Rockauto (among many others, I'd assume) carries them, too.

HTH & G'luck at the machine shop.............ed
 

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1990 trooper 2, 76 Datsun 620
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Discussion Starter · #64 ·
I'd be a whole lot more than disappointed! I'd be having some very stern words with the manager of the machine shop. Any shop that can't handle installing a set of Chevy cam bearings shouldn't be working on engines at all!

And BTW, it's been established for Eons that small block Chev V8 cam bearings can be used in the 60-degree V6.

I'll quote you some good info from the GM 60-degree V6 "bible",

How to Rebuild Your GM V-6 60 Degree Engine by Tom Currao:

Aside from excessive wear, the cam bearings will need to be replaced if you have the block hot-tanked, since hot-tanking destroys them. Replacing the bearings requires special tools and expertise, so save yourself time and money and have your machine shop do it. The shop will use a long rod with a plate screwed onto one end to drive out the old bearings and install new ones. As the new bearings are installed, attention is paid to the alignment of the bearing lube holes with the groove that runs around the perimeter of each cam bearings bore in the block.

<my boldface>

In some instances, this alignment is so far off that the shop has to install the wider cam bearings from a 350ci small-block Chevy, because these bearings are wider than the stock bearings and allow the shop to compensate for misalignment. However, because of the additional width, these bearings have to be precisely positioned to avoid contact with the cam lobes. Unless you're confident you can do this work yourself, it's better left to the pros.

Also, keep in mind that a new type of cam bearings is being used in later-model engines. Instead of the traditional babbit lining, the bearings have a very hard wear surface, similar to that of oilite. These bearings should offer longer service life along with decreased oil pressure loss due to wear. So if you're in the market for cam bearings, you should consider using this later-style design.


Granted this is from 1994, the use of aluminum-clad bearings is quite common nowadays and you should be using that type of bearing for cam, mains, and rods.

IDK if you sent the crankshaft off to the machine shop, but typically they'd use a micrometer set to measure the crank for worn journals, and also put the crank on a set of V-Blocks and do a runout with a dial indicator. If the crankshaft is still Standard, and the journals are nice n' smooth or clean up with a light polish to specifications, then all you need is a set of Standard bearings.

If the crank journals are in poor condition, then they'd be telling you how much undersize all the journals will have to be ground. Or you can just throw the old crankshaft at them as a core, and for a nominal fee they'll give you back a nice reground crank/bearing kit with all the appropriate-sized bearings included.

IDK about you, but I wouldn't have so much faith in the machine shop. I picked and chose all of my parts so I could control the quality.

When you assemble the crank into the block, you still need to use some Plasti-Gage Green to check oil clearances on the mains and rods. I'm assuming you don't have access to a micrometer set.

Another thing comes to mind, what are you doing with your rods? I had mine reconditioned and the machine shop pressed them onto new Sealed Power coated pistons. Not cheap but you know the rods are straight, and the big & little ends are the correct i.d.

I looked up a '94 Camaro 3400 and the main/rod bearings you'd want are the "A-Series". Rockauto is offering those in a Sealed Power and Mahle flavor. Both are quality brands. Enginetech also shows an aluminum-silicone bearing; they talk about that in the detailed description. These bearings will wear much better than babbit and they're far more resistant to corrosion from inadvertent coolant in the oil.

Here are some Sealed Power Bi-Metal aluminum cam bearings for a Chevy V8, I'm assuming something like those would be what you'd want:


Rockauto (among many others, I'd assume) carries them, too.

HTH & G'luck at the machine shop.............ed
Now that they claim they couldnt install those bearings because they just didnt fit, I dont have faith in them, especially seeing the gouges in the ones they did install.
my crank was really rough, so they got me a new one, with .010" main and rod bearings. the rods were reconditioned, with sealed power 00' impala (3400) pistons installed. I'll be getting some money refunded and I may take this to another guy that builds race engines to install the damn bearings I want installed. I may decide to do it myself but not sure what cam bearing tool I should get. Theres questionable reviews on some pricey tools.... Anyway Im not sure which one goes in first, (probably work back to front) then do i orient the oiling holes per a small block install or have that hole oriented to 4 to 5 o'clock like Ben from WOT tech says. I dont have any performance manuals or tom curao's book.
 

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Discussion Starter · #65 ·
one more puzzling piece of info they mentioned about the "test fit with the old cam". the guy says it was really "stiff" but should be "fine".
 

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Yeah, it might be good to leave the cam bearing installation to the professional engine builder. I've never done it, I let the shop do the install. Apparently my shop is capable of doing that!

And "really stiff" is NEVER what you want to hear about your cam's fit with new bearings in the block!!!

What you'd rather hear is "Smooth as Butta"! I'm thinking that your shop didn't get the bearings lined up properly with the cam lobes, causing big issues.

I found some good info on cam bearing installation, it's not as simple as it would seem:


Here's a helpful D-I-Y writeup with good descriptions and lots of pictures. Plus a recommendation for cam tool:


Some good words about cam bearing "clocking":


Some Very Old School tricks and tips in this discussion:


Be aware that the bearings ain't necessarily the same O.D. They go in specific positions and should be marked as such. Definitely follow any directions that come with the packaging.

HTH & Good Luck!...........ed
 

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Discussion Starter · #67 ·
Funds have been tight lately, but I’ve decided I just want to focus on the things I need to get the engine back together and dropped into the engine bay.
the parts and tasks I need done are....
Oil pump and pickup tube
Starter mounted up
Timing set
Valve springs
Motor mounts
Cam and lifters
I’d like to get some factory Isuzu brand motor mounts, any ideas on where to get them? Post a WTB in the classifieds??
 

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Rockauto still lists motor mounts, they're cheap:


Of course, those are aftermarket. You might try Jerry Lemond for OE parts.

JLEMOND here or [email protected]. Use caps or large font in deference to Jerry's Old Eyes.
 
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