Club 80-90 Forums

and the winners are the............... IRISH............

well done guys. 4 bent con rods ??? dont think the crank is bent but the light does make it look that way. whats gone on god only knows. the guy i`ll see tomorrow is a very clever guy. he`s been highly involved in engine devopement on pre production engines so he`s sure to have an opinion on whats happened. these are supposed to be the stronger pistons and rods.

and to note this engine has not been over reved.


lee

Give the engine to Jed. They can be bent together.
Russel

Rods have probably hydrauliced on the engine oil as the crank case compression threw it into the intake.
What was the condition of the turbo prior? any bits of the compressor in the crowns?

Where did you get your injectors Lee?

Rods have probably hydrauliced on the engine oil as the crank case compression threw it into the intake.

I might go with that after due consideration, but for sure, a helluva lot of fuel at some point and possibly not enough air.. suddenly.

When the dust/diesel soot has settled, what say we get the melted piston and bent rod put together on a plinth as a 'nauts Annual "Comedy of Errors" Award?

silverbullet wrote:When the dust/diesel soot has settled, what say we get the melted piston and bent rod put together on a plinth as a 'nauts Annual "Comedy of Errors" Award?

we need something to repace the broken diff award

Well the rod with the holed piston is bent also. His thoughts are that the rods were bent before and due to the piston being low in the bore the flame front has not been contained in the bowl and has burnt in to the squish area. If he's right then the question is when have the rods bent. Going to get the injectors tested as they were new in january.

Something in the melted pot had gone incendiary on the piston crown, that's for certain. Could a faulty injector have caused a carbon deposit to build up and start to glow, leading to meltdown? Another question - do diesels have piston cooling oil jets that could get blocked and cause it to overheat the crown?
Did it blow soot under full power or was it always clean?
I don't know enough about diesel mixtures and what happens when it all gets marginal, hence the queries.

Dont think it ever blew soot.The .240`s soot a bit at about 1.2 bar. my .230`s at 1.5 bar were clean.

oil squirters are clear but the pistons are not hollow crown ones. probably going to run the hollow crown pistons in the rebore but have to sort the different squirters out first.

engine was turning @ 3500rpm when it let go. i`m going to have to get the spray pattern on the injectors tested too.

im struggling to keep up with what has occured here but....you have one melted piston? (not "holed" but melted at the side yes?) and 4 bent rods!!

to bend all 4 rods the thing must of been running a stupidly high boost and fuel..2 bar is only a smidge over the upper max boost pressure so it wont bent rods...was the engine "feck" to start with...well these enges dont run for long with 1 bent rod let alone 4 as the rod tends to hit the bottom of the bores, if it had been in a flood it might of done all 4 rods but normally only one or two.

the melting i suspect is caused by one bad injector causing a hot spot...and over boost at max turbo pressure due to no wastegate control maybe? then engine has maybe drunk its own oil due to high crankcase pressure because of the piston blowing causing rod bending or the rods have been bent a while due to oil being sucked up the breahter maybe? or wading?

Cranks dont bend..they snap

Oh...and no petrol has been put in has it of course?

it is an odd one. rods aren`t bent enough to hit the squirters.

i`d love to know exactly what has happened but i may never know. the rod is bent on the burnt piston so i think its fair to presume that rod has not been bent by oil hydraulicing as there would be a bit hole in it.

were they all bent before?

engine was running fine, smooth with very little vibration. good starting when cold.

priority is to get it back running and reliable so i`ll be putting it back to std afn spec bar i`ll use the hollow crown pistons just for a bit of saftey.

Did it have charge cooling? has it dumped a load of water into the inlet?


Tiz an odd one i agrees...

Whats the head like?