My buddy spun a couple rod bearings. He caught the knocking sound before any damage to the block. There were some filings at the bottom of the pan, and there may be a small knick on the crank rod journal.
My questions are:
1. Can he just replace the damaged bearings without pulling the head and the block?
2. If he chooses not to have the crank micropolished, but just to replace the worn bearings, what would happen to the motor?
3. Does he have to drop the crank and get the journals micropolished?
4. What needs to be done in a situation like this?

 

I would definitly drop the engine. IT makes it alot easier to do the rebuild. I would definitly have the crank micropolished to get the knick out. Yes the crank has to be dropped

 

1. Yes sure you can - but not recommended. You should pull the head to determine if there is any damage to the piston walls (like mine had when I spun a bearing and shut off immediately)
2. You will have potentially too much play between the damaged crank and the new bearings - the new bearings will probably not last very long.
3. Yes - although if the journals are out of spec a lot - it will be cheaper to buy a new crank
4. Depends on what a thorough assessment of the car turns up.

 

There is no damage to the cylinder walls or the pistons, so I think that he may be in the clear there.
Isn't there a way to measure how much play and use the appropriate coloured bearing?
Well those will be measured. What sort of price does the crank go for?
I think that he just wants to either replace the bearings only, or polish the crank and replace the bearings. How badly did your crank get damaged when you spun the bearing and what did it cost you to fix?

 

bump

 

If he actully SPUN the rod bearings in the rod then chances are he needs a new crank and definitly new rods.If the crank and rods turned blue or black toss them.

 

yea do it right and change the crank as well otherwise the knock will come right back

 

Thanks for the advice guys, I think that he decided to get a new crank and bearings.

 

Dont forge to check the rods also. Chances are that it got scored also.

 

How many rod journals got damaged? Any mains get damaged? Is he willing to sell the crank?

 

I think that two of the rod journals and one Rod got damaged. No mail journals got damaged, but the rod journal was blue/black from the heat.

He did not even try to get it machined, when I called him today to pass the info along, he had already pulled the crank and tossed it. I think that the mechanic already claimed the crank, I was trying to get it for myself so that I could get it knife edged and lightened, but no such luck. (yes I know the Honda cranks do not have to go through the oil in the pan)


[Modified by canuck-mx6, 10:58 PM 5/27/2002]

 

please forgive me for being stupid but what does it mean when you "spun rod bearings"
i just like to know the mechanics of it and how it occurs. all i know is that it fukks up the motor

 

The bearings sit between the crank and the rods. The part of the crank that the rod attaches to is called the rod journal. The bearings ride on a layer of oil which prevents the metal to metal contact. When the bearings fail, you get metal to metal contact, and that messes things up.



The bearings are labelled as 10 in the picture


[Modified by canuck-mx6, 12:36 AM 5/28/2002]

 

It still has to spin through oil that shoots from the oil squirters.

 

how can that occur? high revving? no oil?