Ok, due to a loud knocking that is coming from inside my block, and on statements from a guy who knows about such things, l have probably spun a bearing. I forgot to ask, and he left on a trip.

What is the best, worst, and most likely case here? Will l need to have the block into a machine shop? ETC.

Also, what exactly am l looking for when l get it open? l would imagine that it would be pretty obvious, but.....

All help appreciated
Clayton

 

does it stop rattling under load? Most times a spun bearing will rattle when you let off the accelerator, and stop when the engine is revving or under load. The sound starts almost like spark knock, but gets progressively louder as days go by.

The fix is grinding the crankshaft bearing surface down and fitting new main bearings.

------------------
Michael Bangert
mbanger@iupui.edu
'88 5.7 IROC
'99 CBR1100XX
'00 Silverado LT

 

check to make sure the damper is tight. I had an engine I was sure was headed for the grave because it was knocking so loud, but really the bolt holding the damper on was just loose.

------------------
Michael Bangert
mbanger@iupui.edu
'88 5.7 IROC
'99 CBR1100XX
'00 Silverado LT

 

Another thing that will male a noise like a spun bearing, is a cracked flex plate.

Has your oil pressure (or your car's) changed any since this started up?

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

I spun a connecting rod bearing in my 77 Blazer equipped with a 305. (truck was laying almost on its side in a ditch and I cranked the engine to try and get out, oops, no oil in the pick up!)
The thing was loud at start up until oil pressure built, then it would quiet down. I dropped the pan, popped the connecting rod cap and polished the crank as best as I could and installed a new bearing. Lasted for a little while but then a main bearing went. So I sold the truck.

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

You can "trash" a bearing and you can "spin" a bearing. Which ever one it it, will decide your course of action.

Trashing a bearing simply means that its beat up, scored, wore out, whatever you want, but has NOT SPUN.

Spinning a bearing means that it stuck to the crankshaft, and spun inside the journal.

Spinning a bearing is the worst case scenario, because when you trash a bearing, you can get away w/ a turned or new crank w/ matching new bearings. If you spin a bearing, you are looking at a turned or new crank, matching new bearings, and re-sizing or replacing whatever the bearing spun inside.

For example, if you "spun" a rod bearing, that means the the bearing stuck to the crank, and spun inside the connecting rod, and wore the connecting rod out-of-round. simply installing a new crank and bearings will last untill you crank it up and that bearing takes the shape of the worn out rod. You will either have to have it re-sized at a REPUTABLE machine shop, or replace it.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen

GM Master Tech
ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

i had a spun #3 main in my 350 that was in my 85. the crank was good, miked pretty much dead on for.010 under. not a mark on the crank. the block was trashed where it removed metal from the bearing seating surface. the guy i got it from said he rebuilt it not long before i got it, hard to say what he did but i'm sure he screwed it up.

------------------
ICON Motorsports

1st & 3rd

 

yeah thats if it doesnt throw a rod first!!!


------------------
89 firebird formula

356 10.5:1compression
comp cams xe262 cam
performer rpm intake
#1405 edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner
msd 6al
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

 

Assuming l "trashed a bearing" as GMTech said, what do l need to look for or be careful of during reassembly. (Im very good at getting things apart, but putting them together is sometimes a challenge) Are there any common pitfalls l need to watch out for?

This will be my first time tearing apart the bottom (or top for that matter) end of an engine. So l want to do this w/ the least amount of blood, skin, tears, and money loss as possible.

Clayton

 

Allright, here is how it is.

take the motor out of the Car, No way around it on our cars.


Flip it upside down and bust the oil pan off, note the setup inside.

Take the oil pump off, and start taking off Rodcaps, Remember wich one is wich!

When you find your spung bearing, figure out weather it is spun or trashed.

Once you decide weather your in it for a turned crank and some bearings, Or gonna end up with Reconned Rods, Pull off the maincaps ( remember wich is wich ) and lift the crank out. Take it down to the machine shop and the guy will tell you if itis turnable or not.

If you drive the car for a while with this condition, You will turn a 70$ turn + bearings and your time Job to a 200+ Job for a remanned crank.

its not to hard, But intimidating. Putting it all together is the reverse of dissasembly, but there are some specifics to watch out for.

Ive done this once before, But I dont feel confident giving advice because Im Not sure how good a Job I did, Ill let someone else with more experiance tell ya the specifics of putting it back togther.

and good luck, this is about the worst thing that can happen




------------------
60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

 

use number punches to mark every rod, every rod cap, and every main cap. under no circumstances can they be mixed up! you should put rubber hose on the rod bolts to keep from damaging your crank any worse than it already is.