hudman

As most of you know, my motor was recently rebuilt because of 2 spun bearings. Bearings were checked by a shop last summer and I do not recall them "scraping" off the Plastigage residue. If they just buttoned it back up with the residue still stuck on it, would that be enough to wear it out over 500-750 miles. You hear of specks of dirt etc., but I do not know if that material is strong enough to wear it out.

Thanks.

Greg

No.

wombvette

Na, Its just wax.

yellow 72

Not a chance :nonod:

Mike :cheers:

ZL1powr

The plastigage disolves in oil.

Desertdawg

:iagree:

If you spun 2 bearings that fast, I would guess at there being an oil delivery problem...Or they didn't torque them correctly.

Rockn-Roll

Yes. It has nothing to do with the material involved. ANY material between the bearing and the journal will cause torque readings to be incorrect after the material is melted and washed away. If they left a plasti-gauge on the bearing then they did a big no-no. Not only will the torque reading be off, but the material will prevent parts of the bearing surface to get lubricated during initial startup...it's the initial start up when the most damage is done. They should have used warm oil or solvent to rinse the plasti-gauge off.

I don't use plasti-gauges myself as I have a vernial caliper with precision down to five thousands of an inch. I measure the journal and check the tolerance listings. I also measure the bearing thickness and the inside diameter of a torqued down bearing cap. I also purchase bearings from a reliable source so that I don't have to mess with the new bearings other than soaking them in oil overnight and then installing them.

It's too bad you didn't video tape them leaving the plasti-gauge on.


[Modified by Rockn-Roll, 4:45 AM 5/1/2003]

norvalwilhelm

The quickest way to spin a bearing is to let it go before the oil temperature has warmed up. Bearings are designed to operate at 180 degrees. Backing it out on the road and gunning it is asking to spin a bearing.
Make sure the water temperature is up to normal before any aggressive driving.
Also bearings are designed to run at around .002 clearance. Their oil consumption goes way up after this plus their load carrying capacity goes way down with just .001 increase in clearance.

NHvette

:skep: :skep: :skep:
Yeah - the plastiguage will melt and dissolve ... but ...

You need to keep the bearings dry and clean to plastiguage them.
Are you saying that they left the bearings in this state when torquing ?
They should have been lubed at assembly. I always remove and clean
before lubing and assembling. Maybe I'm paranoid - but better safe than sorry.

:seeya

joeveto

<<other than soaking them in oil overnight >>

Rock n Roll, can I ask why you do this?

john's '81 mouse

Quote: "You need to keep the bearings dry and clean to plastiguage them.
Are you saying that they left the bearings in this state when torquing ?
They should have been lubed at assembly. I always remove and clean
before lubing and assembling. Maybe I'm paranoid - but better safe than sorry."

:iagree: I used assembly lube on my bearings, since engine was together several days before being re-fired.

The Dude

:withstupid:
Me, too.
Lifters, maybe. But bearings?

hudman

They removed the caps, put on the Plastigage, torked it back down to "spec" removed the cap again, checked the Plastigage with the chart on the package, said "that looks OK" and slapped it back up there.

I would say that they do not need any more of my business.

Rockn-Roll

The bearing material is porous and will absorb oil. Under pressure it will take a few seconds before the bearings are saturated. Just placing some oil on the bearing will not allow it to soak in well enough. Thus, soaking them overnight will allow enough time for the bearing material to become saturated with oil. I also soak all my engine parts (and transmission parts) in oil before assembly...that way nothing gets rusted. A brand new reground crank will have a thin coating of oil on it to protect it, but I wash everything down with solvent and water then allow to air dry in the sun (California has lots of this during the summer)...When I'm sure it's totally dry (about 1 hour in CA) then I dip it into a oil bath in a large tub...there is sometimes a small amount of surface rust that I rub off with oil...I pour about 2 gallons of oil in the tub so that everything is completely emersed including the crank. I don't use prelube, so when I start the engine up it's ready to rock-n-roll! I let the engine idle for about 5 minutes to get it warmed up, adjust rockers, timing, and carb. Then I shut down, clean up, and get it out onto the road for a mild drive to make sure nothing is leaking or anything. Then, I drive back to the shop and clean everything up...inspect everything the last time, change the oil...but leave the current filter in there. Then I take it out to see what it can do. I've never had an engine throw anything on me...no spun bearings etc., and I'm about the hardest I can be on my cars.

I hope that explains it.

Desertdawg

I guess you have never read the cam break in procedure. :confused: