Rebuilt engine knock...

[CraigKennedy]

Hey yall, I just got back around to my rebuilt engine, I got everything back together today, cranked up and let run or 5 minutes, everything was going fine, I idled it up to high idle for a few minutes, It started knocking so I quickly cut it off. I noticed that as soon as it started knocking the overfill hose on the radiator shot out a half pint of antifreeze.
I pulled the oil dipstick, oil was fine, no water, I stuck a magnet down in the bottom of the oil pan, and pulled out a small metal shaving

Anybody know what could have happened?
I added assembly lube to all the bearings, torqued all to book specs, and oiled the cylinders before starting, and primed the oil pump.
Oil pressure is still good, I'm going to pull the sparkplugs now and look down at the cylinders
Somebody care to point me in the right direction?
Thanks,Craig

[ricky racer]

I assume you plasti-gaged all the bearing clearances to verify they were correct? Ring end gaps checked and adjusted as needed?

[CraigKennedy]

Ricky, I plastigauged all the bearings, were all in correct clearance, machinist said that there was no need to set ring gap because he had hone the cylinders for the rings already, I did check over them anyway, all had enough clearance.
I just dropped the oil pan and checked all the bearings, every one has scratches, the middle main bearing had 2 notches cut on both sides of it?
I'm uploading the pictures of them right now

[CraigKennedy]

heres what I found

[ricky racer]

Wow!! I guess the next question is were the caps correctly oriented correctly and in the correct location? I have no idea what could have caused the divots but a close inspection should reveal what caused them. It is obvious that the center main received a lot of side load evidenced by the worn away bearing material. The real issue is, what caused this wear? What is the side to side clearance between the center main bearing and the crankshaft? Is the bearing material worn away on both sides of the center main bearing or one side? Is it worn away from the upper main same as the lower? Was the oil pump primed before start-up?

[Eugene]

Center main bearing/thrust bearing. As a guess, the crankshaft is moving forward and back. My guess is that if you check the #2 and #3 rods and rod caps, you will find scuff marks similar wear on the thrust bearing.

Scratches on inserts. Contamination from the oil galleries, not clean work area, or crud in the assembly lubricant.

Were the oil galleries roded out and flushed? Was the engine block dipped/boiled out?

[CraigKennedy]

Ricky, Eugene; the block was boiled at the machine shop, During the assembly, I blew out the galleries with compressed air, and brake cleaner, and more air, I used engine assembly lube, it did look like it had been on the shelf for a while, but I opened it myself, I primed the oil pump before start up, it was on 35-30 Lbs while it was running, had alot of oil pressure coming from port in filter housing. Ricky, the center bearing has those same notches on both sides of the bearing

[Glen]

Hi,
The notches in the sides of the bearing are made in it, for oil to run down, probably to lube the sides of the bearing. Car engines have the notches too sometimes.

[CraigKennedy]

Glen, thank you, I didn't think that I had found enough metal in the oil for those notches, now if i could just find out exactly why the bearings got trashed...

[ricky racer]

Craig, maybe take the bearing to the machine shop and ask them. They've got a lot of experience and maybe they can offer some insight.

[Papa's Cub]

Craig, I don't see enough wear on those bearings to indicate a cause for a knock. It doesn't take much (foreign material) to score/scratch them. I'd like to see that piece of metal you found in the pan. I can't imagine a relationship between the bearings and the antifreeze escaping from the radiator vent tube. It's going to be interesting to discover the culprit there, I think it's going to be a piece of metal that didn't get flushed out prior to re-assembly. Good luck and keep us posted, Tom.

[Eugene]

Have you checked for the knock being external to the crankshaft and rods, the crankcase?

Pressure plate finger came loose. Idler gears front of the engine. Loose flywheel.

Internet check and some automotive thrust bearings have the cuts/grooves on the side similar to the photo.

[CraigKennedy]

Tom, I will post with the findings, I'm going to try to remove the head tomorrow, remove the pistons, and have a look around.
Right off I couldn't think of anything pressurizing the radiator like that either, besides head problems, but there was no sign of water in the oil.
Eugene, No I haven't, I torqued everything down with a torque wrench, besides the oil pan and front cover, I did take a look at the gears from the oil pan, didn't see anything right off, but that doesn't mean anything.
and yes I did see a picture of the center with the notches already in it, makes the situation a tad bit better.

BTW, does anybody know if the main bearing can be removed and installed with out pulling the crank?
Thanks guys, Craig

[Eugene]

Does anybody know if the main bearing can be removed and installed with out pulling the crank?

http://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c152800692b7.

Down a bit in the above link, termed rolling in and out of a bearing insert. I have use nails to roll out inserts.

Loosen the bearing caps on the journals from which the insert is not being removed. You need to have two of the three main bearing caps in place while you remove the insert your are working on.

[RaymondDurban]

...
BTW, does anybody know if the main bearing can be removed and installed with out pulling the crank?
Thanks guys, Craig

I'm pretty sure you can, if you swap one at a time with the other two caps loose, insert the bearing from the right side, and you are careful.

**Eugene beat me