Thread: Thought i had joined the broken crank club but NO!

Well today seen a mirror image of tuesday.. pulled the passenger side head and bugger me not a mark on the piston crowns or the valves.. this is good but bad .. good is that there is no obvious damaged to valves or pistons after such a major failure at 95km/h towing not far off 3ton..
The bad is im not sure what was the reason i couldnt fully rotate the engine..
As would be expected the engine rotates freely with the heads off and the bores etc look good so nothing it seems has fallen down internally to obstruct anything.
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You should take the heads to an engine reconditioner and ask them to inspect them. You’ll find something is out of round.

Originally Posted by DiscoJeffster

You should take the heads to an engine reconditioner and ask them to inspect them. You’ll find something is out of round.

Yes i will , going to take the ones i bought as well and get them checked before i put them on..

Cheers Bulletman

You look like, aside from pain and anguish, you might come out of this quite unscathed. Plus you’ll have have “fun” in the process.

Originally Posted by DiscoJeffster

You look like, aside from pain and anguish, you might come out of this quite unscathed. Plus you’ll have have “fun” in the process.

Unscathed is proberly the wrong word , some of the jobs to get parts off made my hands and wrists looked like i was using a cheese grater to remove the dirt... but yes i get what you mean

Im not disappointed that i pulled the heads as with the rocker damage i would always have wondered if a valve was about to break if i was lucky enough to put the belt on and it rotated without issue.. of course my bank account wishes i put the belt on and it rotated without issue...

Will order what i need plus a new oil cooler and few other bits then start the rebuild process..

Cheers Bulletman

There should some marking - maybe ever so minor to show where a piston touched the valve/s and pushed the valve up and broke the cam cap bolts etc - failing that I would especially look at the valves next to the damaged cam cap bolts.

Originally Posted by 101RRS

There should some marking - maybe ever so minor to show where a piston touched the valve/s and pushed the valve up and broke the cam cap bolts etc - failing that I would especially look at the valves next to the damaged cam cap bolts.

Thanks 101RRS,

The piston crowns are not flat they actually have 4 x half moon indents which align with the outside half of each valve so i think as long as the valve stems are straight on impact there will be very little impact to the piston crown outside of the indents in the pistons.. i had 6 smashed rockers on 1 head and 3 on the other yet to the naked eye there is no noticable impact damage between piston and valve.. not saying its not there with bent valve stems but if you didnt know what had happened you would say the head has no visable damage..

which begs the question as to how many failed oil pump engines were just tossed because of what was assumed may have been internal damage.. that is for another thread anyway..

I will eventually get around to stripping the heads down to see if its terminal but from what ive seen the rocker gear seems to be the weakest link and it could be a smart design feature... but who really knows..

Cheers Bulletman

Originally Posted by Bulletman

Thanks 101RRS,

The piston crowns are not flat they actually have 4 x half moon indents which align with the outside half of each valve so i think as long as the valve stems are straight on impact there will be very little impact to the piston crown outside of the indents in the pistons.. i had 6 smashed rockers on 1 head and 3 on the other yet to the naked eye there is no noticable impact damage between piston and valve.. not saying its not there with bent valve stems but if you didnt know what had happened you would say the head has no visable damage..

which begs the question as to how many failed oil pump engines were just tossed because of what was assumed may have been internal damage.. that is for another thread anyway..

I will eventually get around to stripping the heads down to see if its terminal but from what ive seen the rocker gear seems to be the weakest link and it could be a smart design feature... but who really knows..

Cheers Bulletman

I know the engines are totally different, but you get that kind of minimal damage on 300TDi engines as well, with the straight valves just pushing back through the valve train.