Std size new big end bearings + std crank => can't turn over by hand *conrod bent?*

**RobST162** · 24-03-2009, 10:31 PM

any thoughts guys?

This seems a little peculiar to me, I mean, standard big-end bearings are the smallest you get, and the crank here is stock.

I don't understand, kinda frustrating.

I applied a nice moly-lube to the surfaces, pulling a cap off again, I can see that the lube has been forced out of the bearing with very little residual lube on the bearing.

I would understand if I'd bought oversize bearings by accident...but with standards?

**RobST162** · 24-03-2009, 10:56 PM

I can turn the engine freely when the torque on the caps are as follows:

1: 30 ft/lb
2,3,4: 49ft/lb (factory torque)

when I bring #1 up close to 40, it gets hard, and 49 veeery tough (nigh imposs) to crank the engine by hand, how does THAT work?

**oldcorollas** · 24-03-2009, 11:17 PM

no oil underneath the bearings?
can you torque up the cap with the bearing and check internal diameter?

is that journal on the crank scuffed or galled or anything? measure it if possible...
other possibility is that one of the bearing halves is a bit out.. swap with other # and see?

**fixeruperer** · 24-03-2009, 11:27 PM

was this crank and/or caps from the block originally ?

have you tryed swaping bearings around ? as oc said

it will probably need a line bore, have you got the crank checked out ?

**oldcorollas** · 24-03-2009, 11:58 PM

(i'm assuming he still wants to do this with engine in car?

)

**The Real Roadrunner** · 25-03-2009, 12:49 AM

Have you mic'd the crank and journal?
have the rods been closed and honed?
why were the bearings replaced in the beginning?
what did the original bearings look like when removed?
need more info

cheers
linden

**oldeskewltoy** · 25-03-2009, 02:35 AM

plastigage........

#1 journal could be ever so slightly bent?

**oldcorollas** · 25-03-2009, 02:45 AM

which standard size? how different are the tolerances on the stock bearings?

**amichie** · 25-03-2009, 05:33 AM

Why use moly lube. You should use engine oil only for assembly.
Clean it out and use engine oil instead.

**JetspeedCamry** · 25-03-2009, 05:53 AM

Originally Posted by amichie

Why use moly lube. You should use engine oil only for assembly.
Clean it out and use engine oil instead.

Molylube is only for new/reground cam wear in in isn't it?

**jeffro ra28** · 25-03-2009, 06:03 AM

Agreed, moly lube is no good for bearing assembly. Its really only good for thread torquing.

Might sound like a silly question but when you assemble are you making sure the tang on the cap is on the same side as the tang on the rod?

Check the part numbers on the back of the bearings, they do fuck up packaging very occasionally.

Did you blue check the bearing cap faces?

Check that the chamfer on the bearing edge is sufficient and that there are not any "shiny" spots from interference when it was torqued.

**RobST162** · 25-03-2009, 07:08 AM

hey guys thanks for the replies

i'm doing it in the car, don't feel like a full rebuild right now, #1 bearing was stuffed and the crank has some non-prohibitive imperfections on the #1 journal, but nothing that would thwart my purposes here

I haven't got plastigauge here, but the Haynes manual says to use a moly lube at this point.

The bearings when they came out, (bad as they were in #1) didn't show evidence of warpage wear.

I might apply some blue in and put some swapped bearings in and see what happens

**thechuckster** · 25-03-2009, 09:04 AM

Rob: my motor was stiff to turn after tightening everything as per specs - i used some honey-like engine-assembly lube on everything. It was easy to turn with a socket and 250mm t-bar.

**RobST162** · 25-03-2009, 09:24 AM

guys, I think my conrod might be bent (maybe why the #1 bearing failed so badly and the others were normal wear)

#4 Journal and rod end

#1 Journal and rod end

**oldcorollas** · 25-03-2009, 10:51 AM

it just looks rotated in the bore. there shouldn't be anything stopping it (apart from friction) from straightening up...

although if it is actually bent, then it will put funny loads on the bearing also..

can you try to rotate it back, then retighten the bearing with just engine oil? see what happens?

good luck!

**RobST162** · 25-03-2009, 10:53 AM

riiiight.. thanks Stewart ok

i'd kiss u but....

**oldcorollas** · 25-03-2009, 10:57 AM

"but i'm just an internet entity" ?
yeah, i get that all the time

heh heh

after you did the bearings first time, did you put engine thru a few rotations? if you could do up the caps with that much twist, then.. it'd all be rooted

i'm no engine builder, but are the shiny edges on that rod (and cap?) a point for concern? is it flat in there?

**RobST162** · 25-03-2009, 11:15 AM

yes the are a cause for small concern, it's not really unflat, more discoloured (from the bad bearings blah blah)

and I'm sure it isn't optimal, this engine will need a re-build at some stage, but right now I just need something going

ok, have have swapped the #1 and #4 new bearings, used engine oil, and now with #1 all nice and tight (and rotated back, thanks Stewart - so stressed I didn't even think of that), and with #1 at torque (and 2 and 3) the engine is fine, but when I tighten up #4, it locks up

I've checked the stamps on the bearings, they're the same, but I am beginning to think something's up there

**neal** · 25-03-2009, 11:28 AM

Man plasti gauge is $5 or so from any auto parts dealer. i'll be plasti gauging it to make sure something else is up.

**RobST162** · 25-03-2009, 11:51 AM

but I can't get smaller bearings so that's weird

ok twisted the piston back around (thanks stewart) bolted the caps back on

i removed what appeared to be the 'dodgy' bearing, it, now it's like if I bolt up #4 tight, I can't turn it

i wonder if the combined torque just makes it hard, however, with just 3 done up to torque it's quite easy to turn.. weird

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