Thread: Information on 4BD1 NEEDED!

That's not a melt-down, this is a meltdown.

This to me shows a piston crown that has broken away for the skirt/gudgeon pin, no signs of meltdown.







I am no forensic metalurgist but I cant see any signs of melting on the piston crown which is the closest to the heat source.

Did the piston seize somehow? hydrolic lockup?

If you look at the piston crown in the first image you can see some lines on the piston side which to me look consistant with the marks on the liner made by the gudgeon pin.

I'd say that the gudgeon pin slipped sideways due to the circlip giving up or the lands around it giving up, the gudgeon or circlip has then marked the sides of the liner and as the piston was still attached it got dragged over the marks and scratched the piston sides. Or the marks are just the result of pushing the piston crown back down into the block on disassembly. The second of these is more likely given that the lines look like they where made by a single event as opposed to several where the lines would be less well defined.

Originally Posted by slug_burner

This to me shows a piston crown that has broken away for the skirt/gudgeon pin, no signs of meltdown.

I agree, there's no melting here, just the first legitimate case I've seen of piston-broke.

Nailing down exactly what caused it would take some time, but likely also not be worth the hassle except for morbid curiousity. Given that it's a very rare type of failure that took 500,000km to happen, with a new piston/liner/pin you're good for another 500,000km minimum.

I'd say it would be more likely a circlip / gudgeon failure as there are no signs of any heat at all. The fracture is about little end level, stress raiser will be the oil control ring groove and oil supply holes to same.
A VERY rare Isuzu failure and not something any of us are likely to see again.

A hydraulic lock in one of these engines even at cranking speeds WILL bend the conrod,and at idle will be a twist and bend

Don't worry Dinty, you are most unlikely to see that EVER again.

JC

G'day All, Not my word/s (meltdown), I knew it was a piston failure ?fatigue around the lower ring groove ?, I'm sure Lotsa (Diana) was just using poetic license .
I do know that it happened all very quickly, over a period of 2 days and a very short distance under 200k's.
C.H.I.E.F, I think you might be on the money there, as soon as I said Land Rover 110 they seemed to get lost in the crowd if you know what I mean, anyway we will wait until the engine is out and I can really check and order parts, cheers Dennis
ps the engine was running just a tad rough, I cracked the fuel lines on cyl's 1 & 2 and it made no difference to the sound/running of the engine, so I thought I had 2 injectors that were faulty, 3 & 4 made the engine idle really rough so I knew they were fine, a consultation over the phone with Murray at Modern Mtrs Dungog, he thought I could have a blown head gasket, he advised me to get if looked at ASAP, I was on my way to Dungog the next morning when at 85kph, it went WHOOSH, BANG, GRRRRRRRRRRRRRR, I turned it off within 1 1/2 seconds of hearing the racket, Murray was a bit shocked at the outcome, it wasn't his fault full stop, anyway heres looking forward to another 20 years of ownership LOL,,. after I pay the bill!!.

O.K. it wasn't a meltdown and I also know that bearings are internally lubricated, but wouldn't the presence of squirted oil have possibly reduced the likelihood of Dinty's failure?

I doubt it, Diana. Lack of oil causes friction = heat...no heat marks...most likely metal fatigue, as stated, circlip, ring, ect. Doesn't really matter.
A 4BD1 in a landy is so UNDER worked it's not going to die ever.

Originally Posted by kaa45

<snip>
A 4BD1 in a landy is so UNDER worked it's not going to die ever.

Except that Dinty's died big time!