Noisy engine...

[Chuck Leeper]

Have a 59K 87 engine w/ a knock. Engine has good oil psi, low leak down, new valve springs.. Otherwise totally original. Knocks cold and warm, at idle.
Oil psi is 60-70 cold, 35/40 warm, at 850 rpm. pump is done w/ the Earl Brown mods, PTE turbo saver.
Flex plate is not cracked. Balancer is GTG, and tight. No ft accessory noises.
Pulled the filter, and cut it open...Very fine sliver dust. Drained oil, filtered it, more silver dust.
Pulled the engine, and found what I call trashed bearings. Appears to have some acid corrosion , and dirt ingestion marking. {POOR maintenance, IMO}
I pulled the pistons, re-torqued the rods w/ the brgs in them, and made some measurements.
These measurements are w/ a snap gauge and inside mic. I also have a dial bore gauge, and will remeasure all w/ that.
Using the high side of the factory tolerances:
#6 Vertical 2.2540-2.2495 = .0045
11 & 4 o'clock 2.2522-2.2495 = .0027
2 & 8 o'clock 2.2510-2.2495 = .0015

I also checked the #5, as the noise appeared to be towards the rear of the engine.
Vertical = .002
11/4 = .0015
2/8 = .0017

I've not measured any others, as of yet.
I am seeing weird wear patterns on the brgs shells. On some, the parting line clearance appears to be some 3/8" from parting line to wear pattern. # 5 & 6 brg shells fell out of the caps when I took them off.
There is no evidence of cap walk, or fretting on any parting surfaces. The main caps fit very tite in the registers. I checked the TIR on the crank main journals. <.0005.
Will have more measurements, crank journal measurements, pics, tomorrow.

Given the loose #6 brg, and the "oblong" condition of the brg, NE1 have comments as it being the probable source of the noise?

Thanks for looking....

 

[SCOOBY DOO]

The Sunnen Rod Machine has a specific gauge for checking the big ends. I'd be curious to know what the measurements are at 12, 3, 6 and 9'oclock. If memory serves I had to 'center' the caps before resizing them...and I'd hone them 2 at a time to keep them from 'walking'. Just a guess, but the rods may have been resized incorrectly...or possibly 2 or more caps were mixed up during reassembly.

 

[TurboBuRick]

Agreed^^ not uncommon for the big end to be egg shaped. I feel weird saying that to you Chuck.

 

[Chuck Leeper]

Agreed^^ not uncommon for the big end to be egg shaped. I feel weird saying that to you Chuck.

I can understand! Mine is, as in Dinosaur egg...
This engine doesn't appear to have ever been into. The brgs are all OEM., heads never off. 59K on the clock.
However, the moron that supposedly had boost "set" at 18#, knew absolutely nothing about the system. The w/g puck/shaft was frozen shut so tite, that I had to remove the lever, and drive the shaft out. That, and a host of other fubar items, contributed to the demise.
A lack of general maintenance, also is a factor.
I'm going to have the crank polished, may have to turn it, have a set of rods built, and go from there.
I've checked the crank. It's dead on the OEM specs, has no measurable taper. Has ingested some dirt, and is scratched.
I'll post some closeup pics of the bearings. An interesting item on 1 main brg: The parting line clearance
shows that the brg had no wear for .650 down on the brg face...

 

[SCOOBY DOO]

If you have access to an elongated dial indicator I'd check the mains at 12, 3, 6 and 9'oclock. If the engine was subjected to one or more overheating cycles...then that will play havoc with the tolerances.

 

[TurboDave]

Sounds like #6 sure is a primary suspect!!

 

[GNVAIR]

From my own experience with a bunch of different engines INCLUDING a turbo Buick engine..........bearing inserts that no longer snap into their registers are usually consistent with damage from repeated detonation. The detonation can actually collapse the bearing insert but not necessarily enough to cause it to spin. This would make sense considering the 18 pounds of boost and the stuck wastegate puck.

 

[Chuck Leeper]

Sounds like #6 sure is a primary suspect!!

Dave, I agree. After checking all the rods, the crank pins/mains, #6 is exactly that!
I've not taken the brgs out of the rods, and checked the bores. I'm going to take them to a shop w/ a Sunnen hone, and have them checked.
I'd put a set of aftermkts in, but that just compounds the expense..This is a near stock cruiser, that doesn't need all those "goodies".

 

[Chuck Leeper]

This would make sense considering the 18 pounds of boost and the stuck wastegate puck.

Your conclusion is pretty much what I've found, working on cars for 60 yrs!
Yep! The moron that made that statement, is exactly that.