traxxasx

ok i got a 97 ls and a 91 ls on the 97 ls the sleeve cracked and it broke ring lands on cylinders 1-3 anyways, rods look good and crank and bearing, motor still ran and didnt hear knock. anyways i was wonder can i swap over the crank, crank bearing, thrust washers, from the 97 block over to the 91 block and use the 91 main caps, and not have to deal with clearance issues? since its all the same just he block is diff, or does the block change clearances? or should i use the 97 main caps, ( i dont think its good to use diff main caps correct)?

if so i will plastigauge it but whats are the clearances?

or do you think it will be okay?

im also going to use the same rods and bearing, with non broken ls pistons and ofcourse new rings.

raverx3m

iTrader: (1)

why would u do that?

4stagecandy

total ****ing failure

0HPTautosport

Why not just use the complete 91? If you're taking the time to tear it down, don't reuse main bearings, buy new ones.

traxxasx

the 97 block sleeve is cracked, the 91 block is good, the 97 block crank, crank bearings and rods are good, pistons ring lands are broke.

91 block has 4 spun rod bearings, pistons are good, crank is bad and rods bearings are bad and so are the rods.


So taking 91 pistons, put on 97 rods, into 91 block and use 97 crank, bearings.

So do i still need to check clearance?

Or does the block will change clearance if it was fine in the 97 block,.

4stagecandy

of course you would need to check the bearing clearances and you should never use old bearings , and if your asking these types of questions you should not be around cars

raverx3m

iTrader: (1)

it just seems like a waste of time since the LS block is very cheap to come by,

jdm Ef-9

good question though... if im installing new rod or main bearings, do i still need to check clearance's????????? i cant imagine it changing sooo much.

hey, maybe a stupid question but idk and this is how i learn. so dont bark. please, lol

bambam

Yes. Actually, when i build motors i don't clearance anything. I don't do piston to cylinder clearance, i don't clearance the bearings or even use a stretch gauge for the rod bolts. I just slap the pistons in and rings and bearings and just torque the **** out of everything so i know i can rev it to 10k.
Just kidding...no really,
I live by the motto, right parts, right tools, right time. Meaning have the right tools for the job, meaning your mics/gauges/calipers read to .0001, you take the appropriate amount of time to assemble it properly, and use the right parts for your application. This = success.

bambam

I like to wipe my *** with used toilet paper. Same think basically.

EG1834

So why is it that you can't reuse bearings?

raverx3m

iTrader: (1)

multi layered metal bearings.
they wear off in different spots.

methos713

do it right the first time...or don't do it at all.

raverx3m

iTrader: (1)

like used condoms *cough*
might be expensive afterwards.

EG1834

Hmm, could you elaborate?

raverx3m

iTrader: (1)

i was reading somewhere that honda and most japanese manufacturers use multilayered bearings.
layers of different metal sandwiched on top of eachother. the top layer is the hardest.
kinda like scratch proof glass which is a regular glass with a layer of some super hard material on top.

EG1834

Yeah I got that, but how does that make a bearing unusable if it's been run?

I can understand if the bearing has been damaged, but that doesn't always happen.

raverx3m

iTrader: (1)

i think the layer that comes right after the bearing surface is soft metal.
i looked at my bearings and most of them if not all have a spot where the top layer worn out.

so you riding your bearings on a soft spot.

u put them in a different engine and you are rubbing another soft spot through the bearing.
soft metals are more "sticky"

i really dont know, maybe someone can explain better than me.
but id think that having them seated in one engine and then putting them on a different surface would just wear them out much faster so you end up replacing them or destroying your engine cuz it stuck.

raverx3m

iTrader: (1)

here i found a lil better explanation

Main and rod bearings each wear in to their respective journal. In the process, microscopic grooves and tracks are created in each bearing shell. When the shells are removed it is impossible to replace them exactly as they came out, so the "break-in" process starts all over again, with the end result being increased bearing clearance.

EG1834

Where did you get that bit of info?

I don't think bearings are broken in like piston rings are. That's why there is the thin film of oil forming a hydrodynamic wedge between the journal and bearing to reduce or eliminate friction, unlike the piston rings.

bambam

There's not always a thin film of oil. Cold startups come to mind.

EG1834

There isn't much load on the bearings either during a cold start up since it's in neutral. Wear is basically zero.

raverx3m

iTrader: (1)

u still see the microgrooves.

if the bearings never wore off there would be no need to replace them ever.
they would be used over and over again.

the conditions are not always perfect. u know. forgetting to change oil for a year or running it dry... etc.
heres an image you can see the bearing is worn past its top layer and has different metal below it.
the middle layer im assuming is a much softer metal for the purpose of absorbing the shock.

EG1834

I've torn down engines many times where the bearings look brand new and reused those bearings. There's an LS2 in the shop right now and every main bearing looks like it just came out of the package.

Those bearings you posted do not have normal wear, those look like there wasn't enough bearing clearance. I don't agree with the statement that you should never reuse a bearing, but I do agree that you shouldn't ever reuse a damaged bearing.

00Red_SiR

....but it's always safer to use new bearings...