Noticed a "tick" when i rotate the crank back and forth

[revhardSHO]

I have my 3.2L down to the block, everthing is out but the crank (oil pump is off also). I was turning the crank and just checking for any free play when i noticed a small, puzzling noise. The "tick" noise I get only occurs when im rotating the crank one way and then immediatly start turning it the other way. Exacly when it starts turning the opposite way it makes a destinct "tick" noise from the Number 3 main bearing assembly. Anyone know if this could be a main bearing? Weird b/c it only comes from the #3 main bearing assembly, thats the only reason it got me thinking. THe crank is fully lubed and all the bearings have oil.

what could it be?

thanks in advance

 

[sdpatt]

Play in a connecting rod bearing?

 

[revhardSHO]

forgot to mention that the pistons are out aswell, so it cant be the rod bearings.

 

[Mr Anonymous]

Well, since in the real world the crank only turns in one direction, you might be making a big deal out of nothing. Where you have the block disassembled to this point, you might as well just replace the mains.

 

[revhardSHO]

Well, since in the real world the crank only turns in one direction, you might be making a big deal out of nothing. Where you have the block disassembled to this point, you might as well just replace the mains.

Thanks what i was thinking, but just want to be sure its nothing since most of this stuff is new to me.

I was looking in my Helms manual a few minutes ago and found that there is a thrust bearing on the #3 main assmbly. I think that must be whats causing it. Any Ideas?

 

[SHOpar]

smithsil89SHO:
Thanks what i was thinking, but just want to be sure its nothing since most of this stuff is new to me.

I was looking in my Helms manual a few minutes ago and found that there is a thrust bearing on the #3 main assmbly. I think that must be whats causing it. Any Ideas?

Either way, since you have the engine that far apart, replace EVERYTHING you can, including any and all bearings and seals. You'll never have a better chance, and you're engine will thank you!

It might also be a good idea to verify both rod an main bearing tolerances if you haven't already.

 

[sdpatt]

The tick is probably from the main bearing halves moving with the crank. They have tabs to prevent rotation in the direction the crank normally turns, but are not designed to stop motion in the reverse direction. They don't have to.

 

[Off Road SHO]

sdpatt:
The tick is probably from the main bearing halves moving with the crank. They have tabs to prevent rotation in the direction the crank normally turns, but are not designed to stop motion in the reverse direction. They don't have to.

Scott,
Wouldn't the indents stop it in both directions? The inserts should be a tight fit all the way around unless he has major wear. The thrust washer halves, I believe, are not a complete 360 degrees around the crank. They are kept in place by little nubbs (technical terminology). You could test this by just removing the thrust washer halves and keeping the mains in. If it still clicks without the thrust washers, I would definitely use plasti-gage on the old bearings to check for existing gap before I spent money on standard bearings.

Tom

 

[revhardSHO]

Its the lower thrust bearing...when I turn it the bearing moves back and forth in the groove on the main journal 1/16". Thats the ticking I here. Anyway does this mean I need new thrust bearings also?

thanks

 

[Mr Anonymous]

smithsil89SHO:
Its the lower thrust bearing...when I turn it the bearing moves back and forth in the groove on the main journal 1/16". Thats the ticking I here. Anyway does this mean I need new thrust bearings also?

thanks

You need to inspect the bearings to be sure. Generating a noise by making the engine do something it never was intended to do isn't the best way to test components.

 

[Off Road SHO]

When you do the mains, they come with new thrust washers. Since you have the engine this far, I personally would put in new mains. Make sure you plasti-gage the new bearings. If your old bearing have STD stamped(standard) on them, then you can put back in new standard bearing and plasti-gage them. If your old bearings have .25 .50 .75 stamped on them, well then you have to go back with new over-size bearings to match and again they will also have to be plasti-gaged. Do not assume the ending gap. Measure it.

Tom

<small>[ March 24, 2003, 03:50 PM: Message edited by: ThomasDooley ]</small>

 

[revhardSHO]

You need to inspect the bearings to be sure. Generating a noise by making the engine do something it never was intended to do isn't the best way to test components.

well you have to remember that in the first place I was only checking for play in the crank, rotating it back and forth, I wasnt testing what it would do by turning it back and forth


How much does plasti-gauge cost? When im measuring the gap, do I put the plasti-gauge under, and then torque the bolts down all the way?

thanks

 

[Off Road SHO]

In my area Plasti-gage costs about 2.00 for a packet with enough to do about 8 to 12 rods and mains. You snip a piece half the width of the bearing. Clean any oil residue off of both sides of the bearing. Lay the little piece of Plasti-gage on top the bearing insert that is already resting in its' journal cap. Do not put it near any oiling holes. Put in your main bearing cap bolts and tighten with a torque wrench according to specs. Now take out the bolts and pull off the journal cap. If it's difficult to remove, re-insert the bolts into the holes but don't thread them in, just use them for leverage and gently rock the journal back and forth as you put a slight pulling motion on the bolts.

The trapped plasti-gage will be smashed into a wide strip. You match up your smashed strip with colored stripes on the package that the plasti-gage came in. Read the gap next to the colored stripe that is closest to yours. The wider the smashed stripe, the smaller the gap, which is a good thing.

I don't have my spec book nearby but if I remember correctly, .006 of an inch is the widest gap permissable, .002 would be perfect for a high revving Yamahammer.

Tom

<small>[ March 24, 2003, 09:57 PM: Message edited by: ThomasDooley ]</small>