Broken push rod

Hi

Any help appreciated on this one please.

My 300tdi 90 broke down on Sunday. It became very loud, lost power and started to vibrate. I pulled over ASAP and found that I'd 'lost' power altogether. After the RAC recovered me home, we found that I had a broken push rod in number 4 cyclinder. It's practically snapped in half. I had a new timing belt put on 3 months ago (about 2k miles ago) so it shouldn't be that skipping that's caused it. Any idea please? I have a new set of push rods and valve caps (that were cracked too) and we're putting them in tomorrow but any ideas on the cause would be greatly appreciated. Cheers.

There is a fairly common fault with the 300tdi whereby the small end bearing on the con rod breaks up causing a loud ticking/knocking, lots of smoke and loss of power. It usually happens on number 4 cylinder but has been known to happen on others. It could possibly be your culprit.

rescue ranger said:

There is a fairly common fault with the 300tdi whereby the small end bearing on the con rod breaks up causing a loud ticking/knocking, lots of smoke and loss of power. It usually happens on number 4 cylinder but has been known to happen on others. It could possibly be your culprit.

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Con rods are not what he says he broke one of.

He seems to have broken a valve push-rod.

Usually this happens when a piston hits a valve, either directly or when a foreign object gets between them when the engine is running. The valves actually go down into cylinders a whole lot further down than the tops of the pistons come up. If the valve timing isn't perfect, the valves and pistons WILL collide, and broken pushrods (or a lot worse) is a sure bet.

Wrong belt timing can cause this even if the engine runs apparently quite well.

I suspect the injection pump is timed correctly on the belt, but that the CAMSHAFT sprocket could be one or two teeth out.

CHECK it!

New pushods are cheap. Buy 8 and be sure.

CharlesY

CharlesY said:

Con rods are not what he says he broke one of.

He seems to have broken a valve push-rod.

Usually this happens when a piston hits a valve, either directly or when a foreign object gets between them when the engine is running. The valves actually go down into cylinders a whole lot further down than the tops of the pistons come up.

CharlesY

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If the con rod breaks up at the small end bearing I would have thought it is possible that it rattles around causing it to hit a valve or debris from the bearing to pile up on one side slightly altering the stroke. (or maybe not). only a thought!!!!

ratty said:

If the con rod breaks up at the small end bearing I would have thought it is possible that it rattles around causing it to hit a valve or debris from the bearing to pile up on one side slightly altering the stroke. (or maybe not). only a thought!!!!

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Dear God .....

What you might think, bears no relation to what happens when a con rod breaks.

The outcome is DESTRUCTION, and generally that includes a hole big enough to put your hand in, in the side of the cast-iron cylinder block.

Basically, "If the con rod breaks up at the small end bearing" you'll be needing a new engine.

CharlesY

at 4500 rpm a piston in a series /defender is travelling around 400mph if it comes loose it int gonna be doing as its supposed to do, seeing as how it int got the piston attached to it to keep it in line.

even a lawn mower engine will throw the rod out the side when it comes adrift. i know this cos thats what happen when i over-rode the gov on me lawn tractor

slob said:

at 4500 rpm a piston in a series /defender is travelling around 400mph if it comes loose it int gonna be doing as its supposed to do, seeing as how it int got the piston attached to it to keep it in line.

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Yu forgotten to take ya tablets agin, Slob?

slob said:

when i over-rode the gov on me lawn tractor

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Viva la revolution

The Mad Hat Man said:

Yu forgotten to take ya tablets agin, Slob?

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is this another daftism?

Sirus said:

Viva la revolution

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al have yer know i got it up to 45mph before the piston decided it needed some freash air

I is more interested in yur monnster lawn mower