post mortem: three 2.5 N/A diesels

[ugly_90]

As some of you know, I've been on several perpetual engine projects. I thought I'd share technical analysis of the bores of the stripped blocks, now that my machinist has phoned me.

Engine #1: Green Abro rebuilt 12J non-turbo type block, cause of death: mechanical, or assembly error

- This exmod engine has unknown mileage. The engine's bores appear ok, some minor staining inside, but it has two slightly slipped liners, which are likely not original. This engine has moderate camshaft wear. The engine was bought from another hobbyist, and was a past " runner ". The engine was never turned over before disassembly, and was found with four cups of cat food in the head's intake, where a mouse had stored his hoarde before perhaps becoming food himself to a neighbour cat, never to return.

The intake was left open during some point in the past. Liners are due to be all replaced, and this one should return from the graveyard.


Engine #2:  Red exmod 11J block,  1995, 84,000km as per original service records. Unknown hours. Cause of death: poor maintenance or accident-related loss of oil while running.

. This one was a related story to the last, it was running until it hit concrete on an army training exercise over a decade ago. Engine was never turned over after accident,  disassembled it to find several cups of grain in the head. Again, a mouse had stored at some point during storage. Bores had minor staining, and were measured to be well out of round. Sleeves to be replaced this month.

In order to have such severe wear on a relatively low mileage engine, its likely that debris in the air or oil, improper schedule of oil replacement, or improper filter or filter replacement schedule lead to its demise. It's also possible that it was ran for weeks on end as an FFR truck, but it didn't have a very long service life with the army before it crashed. It could have been run for miles post-accident, pumping out engine oil on the ground, I'll never know. It had a full sump of old oil when I found it.

Engine #3: Red exmod 12J block, unknown year, appears low mileage by bearing wear. Cause of death: poor maintenance.

- This one had a rebuildable head without any mouse visit. It was a club engine elsewhere, and had a known bad injection pump that leaked diesel badly, it was also known as a "runner", and was disassembled upon reciept, not installed,  or turned over.

Several bores have measured as being very badly worn, more than Engine #2. This engine has original bores, is unrebuilt, and has never had any sleeves since manufacture. This one is surplus, and will likely never be repaired by me, as it would likely require new sleeves and oversize pistons/rings, so I've been told. Several of the bores have very small horizontal cracks, rather the just scratches. The causes of failure for this block are likely much like engine #2.



So, some food for thought. It seems there hadn't been many fully rebuilt 2.5NA in the club before this year, and they are somehow known as been overly robust, or otherwise. In all these case, past maintenance has been a bigger cause of failure than engine type or mechanical failure. But, this is common for most or all engines.

Another point I'll make, is that if you're serious about keeping an engine, and don't know when it was rebuilt and by whom, don't do the easy thing and just start it up, it rarely ends well.

A video of a guy who didn't take my advice on an old diesel is attached. But hey, it probably runs, right?   
Video referred by Alex C.

[Already a Rover]

Hi.  Maintenance... even on a diesel.

The video doesn't show.

Gotta go, but worth reading.

Jim

[Matt H]

If the engine is still in the vehicle I always try to start it. It's a risk for sure but if it's seriously damaged and running it will ruin what's left I don't care too much, it's not like a # matching Dusenberg or 426 hemi cuda or anything. I just replace it with a better engine.

If I'm going to the effort of pulling the engine and stripping it for inspection then it's getting a rebuild anyway.

Lots of (non squaddie abused) engines are able to be revived with a little TLC.

The young lad in the video probably should have used a little less starting fluid and a suitable piece of plywood rather than a rag.