The Stovebolt Site Forums The Shop Area Engine Shop Noisy 261 Autopsy Results

I pulled the noisy 261 out of my truck this weekend and dismantled it. (150 miles)

Here ared the results:

Foreign material in the oil trashed all the rod bearings and to a lesser degree the mains. The freshly ground .010/.010 crank mics OK, however it has some serious grooving issues espically on the rod journals, mains look better but still have some minor grooving. The camshaft and cam bearings look good as well as the cam lobes and lifters. Rods, pistons and rings look fine.

When I started this rebuild, I sent it to an engine rebuilder in Phoenix. I told him the engine was sitting outside in a Flagstaff Junkyard for at least 20 years and was frozen when I disassembled it. I asked him to give it a thourough visual exam and magnaflux before starting any machine work. He cleaned the engine and found 2 small steam hole cracks between the #1 and #2 cyclinders and #5 and #6 cyclinders. At this point he called me with the crack info and recommended scraping the block. I found a diesel heavy equipment machine shop in Phoenix that said they could fix the cracks so I took the block to them for repairs. They fixed the 2 small cracks and said they could do all the he other I needed (Boring, balancing, rod rebuilding, crank grind, head work, etc). They did all this work thinking that the other shop thouroughly cleaned the oil galleries when they magnafluxed the engine and did not re-dip the block.

I assumed that the block as clean internally as it was externally and carefully put all the pieces together in as clean of manner as I could. The problem is when I primed the oil pump prior to start up I unknowingly put a fresh coat of Flagstaff volcanic dirt on all the bearings. RESULT-LUNCHED BEARINGS IN MINUTES.

I'm going to try this again, only this time with a ultra-clean block, new bearings and a .020/.020 crankshaft. Hopefully I can re-use the rings, they still show the break-in grooves.

did they use the plug and stitch method to repair cracks or did they weld it? If it was welding you may want to consider having it align bored. How did the thrust surfaces on the crankshaft look? The only reason that I may disagree with your diagnosis about the volcanic dirt causing the failure is you mentioned that the cam bearings look good. I would think that the dirt would go straight thru the crankshaft and rod bearings right up to the cam bearings so they should at least be scuffed up some if that was the case.

The first shop said they thought I was going to scrap the engine so they didn't do the normal cleaning or charge for it.

The second shop said that I didn't specifically ask for another hot tanking, and they assumed (Because the block appeared clean) the block had already been professionally cleaned and are not responsible for this problem.

I'm going to have to bite this one and chaulk it up to experience.

Don

They used the plug and stitch method. The trust surfaces on the main bearing was smooth but showed copper. The crank surfaces looked smooth.

The cam bearings showed very slight damage, the camshaft mic'ed good and looks almost brand new, the lobes look nicely broken-in and the lifter bottoms look ok except 2 have small circle grooves in them.

I'm sorry to hear about your engine problems Wags, sounds to me like those shops should be on Dancin' with the stars, with that "Double Clutch Shuffle" they did. The next one will run forever!

Some replacement main bearings have copper on the thrust surfaces, others have a babbitt plating. Did you notice which yours had when you installed them? Their present color might be "normal."

I don't see any reason you can't use the rings you have. I would remove the pistons, wash everything thoroughly, then oil the rings and wrist pins when you install the pistons.

Too bad you have to lose another .010" from your crankshaft. But I guess that gets into the category of 'good insurance' for the job. And you will know you haven't taken any shortcuts that may haunt you later.

Harvester

Harvester
The main did have copper showing when new. Clevite 77's.

One of my competitors on the racing circuit pulled the "clean" components of a new engine out from under a tarp in the corner of his shop and assembled a backup engine in a hurry. After about 5 minutes of running, it spun one rod bearing. All it took to trash that one was a mud dauber nest in one oil passage in the crankshaft!

Assume every oil gallery is dirty until you personally establish that it's clean!
Jerry

Jerry

I've learned my lesson, never again will I assume anything on an engine rebuild!!!! That also includes clearances, calibrated torque wrenches, fresh bolts and possible mud dauber nest locations....

Wags

I had to rebuild mine twice also... It hurts. Hang in there better times are ahead.

wags,

Although your situation is a bit different, it always pays to drop the entire engine off at XYZ machine and tell them to call you when it is done and painted! When they do all the operations from tanking to assembling, it is done right because they have no 'out' if it isn't.

All the shops I have ever dealt with would consider it a huge black eye to pump out a faulty product. Automotive machinists are usually perfectionist and take their trade very seriously.

Stuart