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

[RobST162]

riiiight.. thanks Stewart ok

i'd kiss u but....

[oldcorollas]

"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]

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]

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]

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

[neal]

stupid question: Is your torque wrench calibrated.

[oldcorollas]

ok, so you've narrowed it down to a single bearing?
that final bit of torque might be enough to induce a little too much bearing crush.
maybe check the ends of the bearings (where they push together) and see if something is up.

i spose you could try swapping half of one of th eother bearings to find a combination that allows them all the move freely..

if you only torque up the dodgy bearing, will it still turn over?

[RobST162]

are there visible symptoms of crush on the bearings?

It's very very peculiar, I loosened off the other three (now 1,2,3) and it's still super right, so it has to be something in the arrangement of #4 now. So to answer you Stewart, if I only torque up this one, it hates me. (with old bearings, or new ones)

So yeah, I put both some standard old bearings in as well as the new ones. With the same effect. I wonder if the bearing cap has an issue, except i've also used different caps when I tried on #1 and #4, obviously.

I'm off to get some plastigauge.

The new bearings have a visibly wider diameter (ie facing them up against the old ones) than the old tired ones, but I'd expect that. Firmer to push in etc etc.

I am wondering about bearing crush, how to determine if I am getting crush, and what to do about it.

[amichie]

Is the head still on?

You could take that rod out and to the machine shop and have it checked.

[rms]

I wonder if the bearing cap has an issue, except i've also used different caps when I tried on #1 and #4, obviously.

????????????????

[RobST162]

piston's #1 and #4 have different end caps, as in, not the same piece of metal

[oldcorollas]

haven't accidentally put the caps back on the wrong way? or they were put on wrong before? do they have identifying marks to show what direction they should be?

[allencr]

I'd skip the plastigage for now with it having an apparent Zero clearance problem, but then if it really was a bearing that was too thick, then the difference between the 30 & 49 torque wouldn't have done anything, because it would have locked up with a lot less, like 5-20.

The pics make it look like the journal filet/s, the 90 degree radius(undercut?) between the journal & flank, are half full of old nasty bearing to my eyes.

Mic the bearings. A ball bearing or the shank of a drill bit on the concave side can get an accurate reading on its curved surface when using a regular mic with flat anvils.

Is this the order of things? First #1 locks up & #4 is fine, then #4 locks up when using #1's new bearings, and then #4 locks up even when using old bearings. Makes no sense to me and the 'rod rotated in the bore' stuff sure didn't help.

[RobST162]

alright, returned from buying plastigauge and a few hours under the car, i've read all your posts and for those of you who aren't sure, it's all in the car and I don't want to pull the engine yet so seeing what I can do.

thanks for your professional words and allen, i'm sure there's lots of issues as you've described

So, where are we now. The plastigauge returned some very interesting results, some impossibly thin clearances (0.0007 or so) and some 0.0028 clearances too (or there abouts)

So I had some spare caps here and I just did a bunch of combinations with various caps on various pistons till I got the clearances within tolerable limits. Probably not an ideal 'engine builder' solution, but probably as good as you'll get while it's in the car. I vary now between 0.001 or a tad over (maybe 0.0015) and 0.0028 again for pistons 2 and 3.

The larger gaps is more than i'd like, but a darn sight better than it was before I'm sure.

The engine rotates freely now and everything's torqued up.

Oh and an aside, my torque wrench is a way old school very expensive one my Dad bought and it doesn't have an calibration fittings, but it always feels very on the mark.

[oldcorollas]

eek. caps are meant to stay as a pair with the rod, since they are bored/sized that way...
then again.. if it works, it works...

i hope a pro engine builder can comment further...