Assessing an unknown engine

[911hillclimber]

Well done Rob.
Need to get all the parts out and check the IMS gear wheel for damage etc., but looks like a good engine.

If it helps, when my 3.2 blew the alum grains were everywhere in the engine, oil cooler and all the galleries and pipes, just everywhere. I threw the oil cooler away as impossible to flush it clean and be sure I had.

The pump was full of fine alum gains but looked good, so i stripped and flushed it all out and re-used it. Gives 4 bar at 15000 rpm hot. For 2 years now.
A new one will always be a good thing.

Buy a good set of oil gallery cleaning brushes as you will need them.

What a crap rebuild effort it was!

[neilbardsley]

How can you rebuild an engine without cleaning it and leaving broken piston in it? Pistons changed without splitting the case and they thought they got away with it?

What do you think caused the oil starvation? Sealant or broken piston?

Sent from my 22011119UY using Tapatalk

[RobFrost]

How can you rebuild an engine without cleaning it and leaving broken piston in it? Pistons changed without splitting the case and they thought they got away with it?

What do you think caused the oil starvation? Sealant or broken piston?

Sent from my 22011119UY using Tapatalk

Looks that way - either replaced a piston without splitting the case. Or given the bearings look good, maybe they did a good job of a full revuild, but the chunks were hiding somewhere.

I think I'll know more once I've stripped and cleaned it. It's a bit of a mystery because there are clearly mint condition pistons and cylinders alongside overheated ones. I'm not that familiar with the engine design but the pump seems to be at the front and send oil down a galley towards the back. It's the back which appears to have overheated more. I even wonder if it was run with insufficient oil. Or even if the piston rings were incorrectly specified or badly fitted. They've been fatigued up the sides of the pistons on some, but others are normal.

The crank looks well lubricated though. I'm sure an experienced 911 engine person would know exactly what happened.

One con rod is a different colour to the others.

Sent from my SM-G988B using Tapatalk

[RobFrost]

I don't have any experience what the crank bearings should look like. All were seated properly, no rotation. They appear to be mint on the inside.



But on the outside they appear to show signs of oil erosion, which is a surprise to me. Is this normal?



This harks back to when I was splitting the case and I said the through-case bolts were surprisingly loose (but all consistently torqued). Maybe if those were too loose, the oil would pass behind these shells instead of into the crank journals?

Anyway, moving on the crank journals all look mint and measure to 57.025mm which based on a quick search of the Internet is acceptable?



Probably not quite the right tool for measuring it with but I was super careful.

Sent from my SM-G988B using Tapatalk

[RobFrost]

And 62.03mm across the engine bore although that was trickier to measure. Not sure what spec is. Maybe it says in Dempsey.



Sent from my SM-G988B using Tapatalk

[RobFrost]

After making up a cam nut removal tool today I found a bit of time to revisit this broken flywheel stud. After covering up all the journals and threads to protect from spatter, I welded the sheared head back on and it reversed straight out with the mini impact driver.



I used another stud as the earth to avoid causing any pitting to any of the crank surfaces.

Sent from my SM-G988B using Tapatalk

[Gary71]

Good recovery. I guess the heat from the welding was your friend here