Quote:
Originally Posted by Mechcanico Lee
Pistonbroke .....yeah been there hehe
Interesting one this , if it's not a bent rod or it's not running close to the crank counter weight in any way , my next best surmise would be an over revving from cold , if the cars been stolen and in a chase this could be likely and yes it could of been a manufacturing defect and it only showed its face on the one piston .....it's hard to say , we could guess at a lot of things ..
You say it misses from cold , and the codes to do with low fuel pressure on that bank ..... would you say it's like one cylinder down or more or a general unevenness to it .
Has anyone had a Diesel engine run away with its self due to say a turbo failure or sump overffull of oil ..... I've had it once on a td6 Range Rover .... it's pretty scary ...... Billowing smoke and screaming it's nuts off till it throws a rod out , makes a reet mess ......... where am I going with this .......
So in some cases with a major over Rev the high pressure diesel pump breaks up ,the case hardening comes off the rotor and metal debris is scattered around the system .....where does the metal end up ....... yes ,in the injectors , so you end up with low pressure codes due to the back spills dumping it out .... high pressure fuel systems will not tolerate metal debris what so ever , the fuel system is as good as finished , contamination in pump , injectors , fuel rails , swirl chamber in tank , metal debris all in bottom of tank due to fuel returning all the debris back there .
Could this be the reason our v10 is giving codes for one bank for low fuel pressure , if a diesel pump breaks up and that is lubricated with oil , I would say for sure a high pressure petrol pump will break up .
Perhaps it's still able to deliver fuel but not up to spec , perhaps after the car has run for 5 mins or so the cylinder balancing and contribution is ramping the pressure and duration on that bank to get it to contribute to get engine smoothness.
On the bank that has low pressure.....the high pressure pump does it have a return pipe that has a banjo bolt with a basket filter in the banjo , or any return line banjo bolts for that matter , take them out and look for metal debris .
If you need the injectors testing I have a man .....he is Martin Wainwright from Wainwright Bros. look him up on YouTube .... proper professional and will inspect the nozzles and pintles under a microscope to look for metal particles
Lots of theory's and maybes , but to do all the work you already have done there , you have got to get it checked out ..... massive waste to put it all back and it not be right .
Respect to you for taking a big job on like that , most garages just don't want this type of work ....just to long winded and if one small thing is over looked you would be pulling it all back out again .
Lee
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Well gents the new piston arrived, fitted and put all back in and its exactly the same.
I have today removed the engine and striped it down again, I have removed all the pistons on bank 6 to 10 and found to my horror cylinder bore to number 7 is not round. It looks like the piston has been going up and down un true.
All that work on piston number 8 made no difference at all.
My question now is I am told these blocks cannot be bored out as there is 6mm between the cylinder walls and the dealers tell me they don't supply oversized pistons.
Am I looking at scrapping the engine or even the whole car as a replacement block is way over my budget.
Has anyone had this issue before or even heard of it.
I can only assume that the water cooling has been interrupted and the cylinder wall has almost warped.
With just a piston ring sliding square down the cylinder wall there is a gap of 20 thou where the wall is warped.
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19th February 2016, 04:13 PM
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