[mmm]

Confused first timer here.
Anyway, I got my set of main & rod bearings in the mail about a month ago, and finally tonight I head out to the garage to assemble my first short block. As I unwrap the celophane on the Clevite 77 main bearings, I notice that all of them are marked "upper" or "lower"- pretty much a no-brainer - until I notice that I have 2 thrust bearing halves that are marked "upper". Is this a packaging fluke by the factory, or is this just how it is? Having never done this before, I don't know. If they are the same, I don't see why they would bother to mark them both with the word "upper". Also, anyone got any quick tips on applying force against the crank while torquing this one down, I have a generic assembly guide, but it is not Pontiac specific, and I wondered if there was a difference.
Thanks, Mike

I'm right at home in a filthy garage

[mmm]

Thanks again Pontiac people! I guess I'll give them a try. I just wanted to be safe and ask if there was anything that was not 100% clear.
Thanks again,
Mike

I'm right at home in a filthy garage

[Michael Farich]

I could go out and dig out my old C77 boxes and see too, I guess. IIRC, mine were both same and both marked UPPER and clevite over the phone said this was correct per their internal BOM for making up the kits. I would presume that the oil hole in the cap would not be a problem as long as the cap had no matching hole or groove. That way, it would be a blind hole when the caps are torqued down. I don't remember worrying about the hole in the bottom, just didn't think it was such a hot idea to have grooved lowers on an engine that was intended to go several hundred thousand miles before it's next rebuild. Then again, it may matter whether the crank is cross drilled or not. I saw an article online somewhere that said all 455, most if not all 421 428, were cross drilled. the 3" journal engines (400, 389, 354, 327) may not have cross drilled journals, so maybe the grooved lower would be a lesser evil on those cranks? Mike

[mmm]

Thanks Guys,
That's the kind of info I was hoping for! The engine is not going to be ultra high performance or anything, so I think I will give them a try. Will, here is what got me thinking about placing a load on the crank while tightening caps.


Here is an excerpt from a link that I found on this board:


When assembling thrust bearings:

Tighten main cap bolts to approximately 10 to 15 ft.lb. to seat bearings, then loosen.

Tap main cap toward rear of engine with a soft faced hammer.

Tighten main cap bolts, finger tight.

Using a bar, force the crankshaft as far forward in the block as possible to align the bearing rear thrust faces.

While holding shaft in forward position, tighten main cap bolts to 10 to 15 ft.lbs.

Complete tightening main cap bolts to specifications in 2 or 3 equal steps.

The above procedure should align the bearing thrust faces with the crankshaft to maximize the amount of bearing area in contact for load carrying.


The above info came from this page:

http://www.aera.org/Tech/tb1465r.htm

A similar procedure is mentioned in a generic v8 assembly manual I have, so I thought that it might have some legitimacy

Thanks Again,
Mike

I'm right at home in a filthy garage

[Ken -Ace- Brewer]

I have seen the half groove thrust bearings with Cleevite and FM. Now I use ACL bearings. They are from Australia. They are half grooved on all!! And come with a nice coating on them! The sweetest and most concentric bearing I have ever used!
Be Cool,

ACE-P.P.R.

[Will]

Mike,

Now I understand what you're talking about WRT applying force to the crank while tightening. That's not a bad idea, go ahead and do it.

Cheers!

Ace, never heard of those ACL bearings. I'll have to get a set from you and try them myself! Maybe my bearing-hungry engine won't like them and will leave them be.

[Malky]

I figure it is because thrust brg needs a good oil supply to the thrust faces. The groove helps oil get to the thrust faces in the half that is normally not grooved.

[mmm]

Confused first timer here.
Anyway, I got my set of main & rod bearings in the mail about a month ago, and finally tonight I head out to the garage to assemble my first short block. As I unwrap the celophane on the Clevite 77 main bearings, I notice that all of them are marked "upper" or "lower"- pretty much a no-brainer - until I notice that I have 2 thrust bearing halves that are marked "upper". Is this a packaging fluke by the factory, or is this just how it is? Having never done this before, I don't know. If they are the same, I don't see why they would bother to mark them both with the word "upper". Also, anyone got any quick tips on applying force against the crank while torquing this one down, I have a generic assembly guide, but it is not Pontiac specific, and I wondered if there was a difference.
Thanks, Mike

I'm right at home in a filthy garage

[mmm]

Man, Why can't I edit!!!
maybe this will come out as a link...

http://www.aera.org/Tech/bearing1.jpg

Thanks, Mike

I'm right at home in a filthy garage

[mmm]

anyone?

I'm right at home in a filthy garage

[mmm]

Does this answer my own question?
[img]http://www.aera.org/Tech/bearing1.jpg[\img]

You can imagine my confusion to think that
something sealed in the factory plastic would
be screwed up like this, but I suppose I was
lucky enough to be that 1 in 1000. I hope this
isn't a bad kharma sign! [img]/infopop/emoticons/icon_frown.gif[/img]

I'm right at home in a filthy garage

[mmm]

I got this e-mail, and now I am a bit more confused:
The 'upper' shells should have grooves for oil supply & will have the oil hole. The 'lower' shells should have no oil hole & may/may not be grooved. If you have two 'upper' thrust bearings, make sure one has the oil hole, is grooved & fit it to the block, not the cap.

I just looked at them again, and they are completely IDENTICAL, both WITH holes and grooves. That means, according to the above, I should not use them since the lower one should NOT have a hole.
What gives?

Thanks for helping me disect this mess!
Mike

I'm right at home in a filthy garage

[Michael Farich]

Couple years ago I bought a C77 main set 455 std/std and it was just as described above. I called Clevite and they verified it to be correct as per their BOM. Said that it's a fair debate among performance enthusiasts as to whether the lower half should or should not be grooved.

Summer 2002 bought a FM std/std set for use instead of the C77 because personally I plan to put hundreds of thousands of miles on this engine and don't want to be kicking my own a$$ at 200k when the oil light is flickering in summer idling in gear and wondering if it's my grooved lower #4 worn into crank excessively. The FM set had grooved lower for only the #5 bearing and I liked that bette for this engine so I used the FM set. the #5 is so much wider than the rest anyway so maybe it's not as much of a biggie to have grooved lower on that one.

BTW, on the rods, I noticed the C77 std/std set might have been must a hair looser than the FM rod set. Just FWIW in case you have a crank that has slight variance in the journal diameters and the two different brands of bearings might help calibrate that out.

[Will]

Mike,

I'm betting the bearing set you have is a "half groove" set. That is, the shells that are marked "lower" have no groove in them and the uppers do have a groove, right?

It appears that Clevite and FM both decided awhile back that they could save money by not manufacturing a separate lower thrust bearing half. Apparently a full groove is okay on the thrust bearing and all you get is two "upper" halves. At least all of the bearing sets, other than the high performance/competition series 3/4 grooved bearings, I've seen for the last several years have been this way. Go ahead and use the bearings you have, they'll be fine as long as the clearances check out.

As for "applying force against the crank while torquing this one down" - I don't know what you mean. Can you be more specific? Apply what kind of force and in which direction to the crank, while torquing what down? In any case, it is not necessary to apply any force to the crank while torquing down any of the mains. You should rotate it after each cap is torqued to ensure there is no binding, and once all the caps are torqued you should check the thrust clearance, but other than that I'm not sure what you could be referencing.

[mmm]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Will:
Mike,

I'm betting the bearing set you have is a "half groove" set. That is, the shells that are marked "lower" have no groove in them and the uppers do have a groove, right?

<HR></BLOCKQUOTE>

Yep.

It must have also been cheaper for them to mark them both with the word "upper" to confuse people like me! You would think that if they got enough phone calls, they would include a courtesy note in the box or something.

Thanks again, I appreciate your posts.
Mike

I'm right at home in a filthy garage