Alright, so I caught a rod knock right when it started, the car hasn't been ran since, I've been reading my motor is shot, I was told that I can fix it by dropping the oil pan and replacing the bad bearing from the bottom of the motor so i don't need to take apart my motor, is this true? my oil pressure is spot on so I don't think I shattered a bearing, if my crank isn't busted will replacing the bad bearing be a permanent fix or only a temp fix? The knock isn't to bad yet and can be heard when the car is warmed up around 2500rpm,

 

To answer your questions,
Yes you can replace the rod bearings without removing the engine .
I just rebuilt a B series engine that had the same problem, removed and had block boiled , pressure tested , bored , crank checked etc...
Oil pressure was spot on but engine had been over revved.

Replacing rod bearings can be a permanent repair , as long as the mains are good (in my case they were)
The cranks in the LS engines seem to be very strong and have a friction coating from the factory that makes them very durable.

 

Its the halfass way if repairing your bearings. Do it right the first time or pay more later.

 

I have never seen doing it that way work ever, you would have to find a way to cut and polish it

 

Dude is crazy if he really thinks you can just slap on new bearings to repair it..the crank has ovaled out where the bearings go around.the knock noise is your circle shaped bearings trying to spin around that,resulting in the rod slapping around at the bearing area..

 

You aren't very good with a micrometer then. If it's measured PROPERLY, and within spec, it's good simple as that.

 

NO

 

Just buy yourself a used engine an save yourself a headache.

 

Well no ****.if it was in spec,it would not be knocking.

 

not true. the bearing could be screwed and not the crank...

 

The slapping around that was mentioned is from there being excessive clearances between the bearing insert and the rod .
Excessive clearance is often caused from running an engine low on oil, and or high mileage.
With even a cheap micrometer, one can determine run out or a journal that is undersized.
Honda has a process they do to their crankshaft to increase the hardness, and durability.
Calling me crazy is fine ,as I am, but not when it comes to engines .
For the record I also own high performance high revving Ford's , a 347 that spins to 7k all day and has for 10 years that also sprays a 250 shot ,and a 76mm single turbo 32 valve Teksid block in another Mustang .
Enjoy .

 

Enjoy what.

Dude smoked his crank, so what we do with honda motors is trash it!
If the bearing halfs spun even the slightest, the crank is bird food.

Even if they didnt and the OP was subjected to audible knock.
Good as a brick IMO

end of thread.

 

not really you can turn a crank and use oversized bearings depending on the damage

 

Again it's the halfass way of fixing something of that measure. If it was so common more people would take this approach on fixing a spun rod bearing.

 

I can't agree. I've run a cut crank on a small block chevy in the 400 hp range and never had a problem. Find a machine shop that is well reputed and don't be scared.
Maybe the abundance of good motors and cranks that don't need machining are the reason this is not done as much on Hondas, but it doesn't make it half-assed or bad.

If I am doing an engine build for anything, even if the motor is presumed to be good running condition, it would be torn down and inspected/measured out regardless. So what harm is it if you have a freshly machined bearing surface that is a few thousandths of an inch undercut?

 

I'm not gonna argue. To each his own.

 

honda cranks are nitride coated so turning a crank is not recommended.

 

Exactly.let's just hope we don't see another thread here in a month ,titled ''why did my brand new bearings spin?''

 

Exactly. If it was caught in time you may be ok, probly need to get the crank ground, or polished. Half ***? Yes and no. Only difference is the motor is in the car still. It's not like you don't use the same process. Only difference is your looking up at it rather than having it flipped over on an engine stand..

 

I need help !! my b20b was knocking now it wont start made one final noise and never turned back on .

 

You and OP just buy a used B20 block or LS and call it a day! HMO is a good source.