how do I "grade" the bearings?

[andrave]

ka24de rebuliding don't have an FSM and don't know how to "grade" the bearings so I get the right ones. I'm trying to find a cheap fsm but money is tight right now.

[DAEDALUS]

Not clear on what you mean. You want to know which ones to buy after you've measured your clearances and such? All bearings or just some? Just FYI there are 5 main bearings, each is .0001-.0002 different from the next one. The challenge will be measuring clearances with enough accuracy to get the right parts.

[TrunkMonkey]

you only need to be concerned about bearing grades if your replacing the crankshaft with a brand new one.

if you're reusing your old crank, then measure the clearances, and pic the right bearings.

-demetrius

[andrave]

I was told that the KA used graded bearings, which were stamped somewhere or something, and I should replace them with the same "grade" that was in there.

[DAEDALUS]

Well, the manual states to measure for and replace the bearings if you reuse the crank. We don't always do everything the manual says of course. The bearing grades are stamped along the bottom surface of the block (where the oil pan mates up), along the passenger side. They're also stamped on the face of the crankshaft counterweight. 2 rows of numbers, upper row (4 #s) is conrod bearings, lower row (5 #s) is main bearings.For the level of work you're doing, you really should have an FSM. It could save you from some expensive mistakes!

[Ubernoober]

Line-bore, undersize crank and get Clevite oversize bearings. Problem solved. Heh, I didn't say it was cheap, I just said it was solved.

[andrave]

I am getting an FSM. it just isn't here yet. why cut the crank when its in perfect condition? just extra money to blow that I don't have.

[sil80drifter]

what exactly does cutting the crank do? does it usually include cleaning it? because for some of us with previous timing chain guide plastic components all over the oil pan, there may be a chance the crank being contaminated.

How much does cutting the crank usually run?

sil80

[deviousKA]

When the crankshaft journals are ground, they are "undersize" and require different bearings. Crankshafts are ground only when necessary due to damage of the bearing surface (scoring, galling, etc..). You will see .020",.030", .040" in the normal off the shelf bearing sizes. What size is necessary depends on how much journal surface was taken off before it cleaned up with appropriate surface. Thats only for grinding.

You can also get away with a crankshaft journal polishing if there is little damage to speak of. This can be done at an engine machine shop. Usually with a polish you will use std. size bearings unless the crank has already been ground.

If your journals appear to be in excellent condition, and you have no debris in the oil (that would warrant the crank to be pulled) you can most likely replace with same bearing size (usually std. unless the engine has had similar work before). The bearing size will be marked on the backside of the bearing shell, std or other wise.

Checking the bearing tolerance with new (not sitting for years) plastigauge should be done on any assembly. Make sure the journal/bearing is free of oil while doing this, and torque down to full spec. .0025-.003" is the basic tolerance your looking for on these engines, unless your wanting a wider fit for other reasons.