Changing bearings under the car

[YZFR1]

Hi,

i have heard it is possible to change out rod and main bearings from underneath the car. I would like to get some feedback on doing that, hopefully, from someone that has actually done it.

I already have pulled the oil pan and was wondering if there anything else i have to take off before proceeding, besides the main and rod bolts of course?

Thank you for all and any feedback

 

[bryanwheat]

You can, but there is a 99.9 percent chance that it will fail again.

 

[ed1380]

If the crank journals are rough, you'll need to sand it smooth, but that doesn't guarantee it'll hold out long especially if abused.

 

[bryanwheat]

If the crank journals are rough, you'll need to sand it smooth, but that doesn't guarantee it'll hold out long especially if abused.

Sand it smooth huh. Do you realize that the correct oil clearance is about half as thick as a piece of paper. If there is any damage to the crank than you are already out of spec Sanding it will make it out of round and further out of spec along with putting particles in the oil passage.

 

[bcjjones]

Yea im no master tech but sanding a crank by hand isnt anything I would try. Like stated above, the oil clearance is minuscule. I believe its actually more like a 3rd of the thickness of a piece of paper!

 

[2GbTalonGuy]

I would listen to bryanwheat. It will be a huge pain in the ass to do them from under the car, rather than to just take the engine out and have everything well lit and easily accessible. Also, sanding a crank is a very bad idea, as stated by bryan. You should take the crank to a machine shop to have it polished reguardless of the condition of it when it comes out.

 

[BogusSVO]

First... Just why do you feel the need to R&R the bearings?

 

[BogusSVO]

First... Why do you need to R&R the bearings?

Did you spin one? Low oil pressure?

 

[BogusSVO]

First... Why do you need to R&R the bearings?

Did you spin one? Low oil pressure?

 

[YZFR1]

Double post

 

[YZFR1]

My brother has just aquired a 400+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So i think with new bearings the engine should still have some life left in it hopefully.

 

[YZFR1]

My brother has just aquired a 400+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So i think with new bearings the engine should still have some life left in it hopefully.

 

[YZFR1]

My brother has just aquired a 400+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So i think with new bearings the engine should still have some life left in it hopefully.

 

[YZFR1]

My brother has just aquired a 400+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So i think with new bearings the engine should still have some life left in it hopefully.

 

[YZFR1]

My brother has just aquired a 400+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So i think with new bearings the engine should still have some life left in it hopefully.

 

[YZFR1]

My brother has just aquired a 450+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So, i think with new bearings the engine should still have some life left in it hopefully.

Obviously, i will also examine the crank before proceeding

 

[YZFR1]

My brother has just aquired a 450+ hp street car with close to 20k miles on the rebuilt engine. How normal would it be to find some shavings in a car like that? It ran and drove just fine, i just really wanted to pull the pan and check it out.

It didn't look completely horrible at all, just some shavings on the very bottom of the pan. I've taken apart a couple of 4g's before and those looked much more horrible. So, i think with new bearings the engine should still have some life left in it hopefully.

Obviously, i will also examine the crank before proceeding

 

[ed1380]

No that's not normal. If you caught it before the crank got gouged, you can smooth down the peaks of the scratches, but it'll be more susceptible to spinning a rod if it looses oil pressure in the future.

Btw did your brother get a 400hp car by any chance?

 

[davidrosario]

take it apart and rebuild it the right way my friend did the same that you want to do and ended with a spun bearing a month later ended up paying for a whole engine take my advise

 

[CellerDweller]

I agree ^^ the clearances are very tight between the crank and the bearings and if the upper bearings can be rotated and removed easily, then you need to measure clearances to see if they are within specs. You also want the outer surface of the bearing and the block/ carrier to be free from oil when assembling - this would be difficult to ensure if you try to slip a new bearing over the crank.

Remove the engine, take the crank out and measure the clearances. If you don't have a bore gauge or a set of micrometers, use plasigauge which can be picked up in any auto store.