A leg out of bed

[Keith Webb]

From time to time I've seen flathead V8s with nasty holes in the sump, block or both where a conrod has let go. I've also seen Chevrolet 216s with the same illness.



I remember going to look at a Morris Minor once which the seller said had a noisy engine. I could grab the crankshaft pulley and move it all around; it had a broken crankshaft! I didn't bother trying to start it.

My only direct experience with this phenomenon was a Briggs 11hp motor which suddenly went thunk. I was wondering whether it has actually happened to anyone while driving and if not too painful would you care to share your story.

[Luke R]

Back when I was at Tafe completing my mechanics trade schooling.
I was working away, when I heard the scream of a engine at full revs then bang, clunk, rattle, rattle.
There are a number of engines in frame that get striped down and reassembled and one of the holdern red motor having been assembled was started to test run it with the thottle fully open.
Big end grabbed smashed the side of the block.
No harm done to the apprentises that were beside the engine but a few red faces.

Luke

[Richard Farrant]

Hi Keith,

Not actually had a rod break while running an engine, but seen a good deal of them in my working life, from large diesels down to small petrol engines. Common ones were the Jaguar 4.2 engines in the CVR(W) Fox armoured car, they would go big time rod knocking the side out of the block. I had to rebuild a big AEC diesel once, when this happened and the block was specialist repaired, it even broke through the cylinder wall, after repair you could not see the weld it was that good.

[Howard]

When I was just a spring chicken, a one-time neighbor invited me to look at an engine that would not start. From memory it was a Bedford truck fitted with a Holden 6. After a brief search I pointed out that the starter motor was hanging by the electrical cable. Reason? It was dislodged by the big-end of #6!

[hrpearce]

Way back in my collage days I found out the hard way that Hilmin Minx's didn't like being driven at ninety miles an hour for long periods. The engine droped a valve in #3, piston wacked the valve and smashed to pieces, the conrod and gudgen then wacked a large hole in the block breaking the camshaft into three in the process. I herd a loud bang followed by a rattly sounding engine still firing on #'s 1&2 then the windscreen was blanketed in steam. When I looked under the bonet the exhaust pipe was glowing enough to see the damage.

[Mike Cecil]

Hi Keith,

Yep, had a Ford GPW engine develop an electrical problem once, just before I was to change from 2nd to 3rd, there was a very loud bang and no more go. Looked over my shoulder before pulling to the side of the road (Middleborough Rd, just north of Whithorse Rd heading north), to see a long spray of oil receeeding on the road surface in the distance and bits of metal bowling along behind.

When I opened the bonnet, I saw the generator was hanging off at a funny angle (hence the electrical problem....).

No.1 cylinder had broken the rod just below the gudgeon, and then flayed a hole through BOTH sides of the block, punching off the gennie as well as slicing the sump (shallow end at the front under No.1). Also broke the cam shaft into a few pieces.

It was 2 weeks short of Corowa, don't remember the year.

Called my father, who took a couple of hours before he could come and collect me with the tandem (the one you have) and my Toyota Ute. By that time, I had the radiator and all the peripherals out of the engine compartment. Pulled the engine when I got home, and raced a spare block up to the rebuilder to clean up and bore to match the pistons I had.

Peter G and I reassembled the new engine a day or so before Corowa, and left on time. The engine paint job wasn't quite dry when we reinstalled it. We always joked that it had been 'shovelled together' and had a baked enamel finish: from the engine heat on the way to Corowa!!

That rebuild was the most willing engine I ever had: would wind the speedo off the clock on a straight road (wasn't game to go that fast on curves: jeep handling ain't the greatest!). I still have the section of broken cam shaft on my desk: PG found it wedged in the chassis rail while we were reinstalling the new engine!

Mike C

[Keith Webb]

Interesting the way these stories are amusing in retrospect.