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MobileCC
12-12-2013, 10:02 PM
56088

06 2500 125,000 miles # 5 cyl
Knocking sound would come and go away under load ..prior shops replaced flex plate and put a set of rod bearings to try to fix knocking sound ..any ideas on what happen ? Cylinder wall looks perfect ..like nothing happen

Aqua Puttana
12-12-2013, 10:22 PM
56088

06 2500 125,000 miles # 5 cyl
Knocking sound would come and go away under load ..prior shops replaced flex plate and put a set of rod bearings to try to fix knocking sound ..any ideas on what happen ? Cylinder wall looks perfect ..like nothing happen
A shot in the dark.

Injector overfueling or spray pattern?

3.3.1. Washing away of the oil film on the cylinder wall

http://www.sacea.org.za/.%5Cdocs%5CSAIT%20Referaat%20Inspuiters_2_Shrunk.p df

Some good info here too.

http://www.boosttown.com/engine/piston_damage.pdf

vic

lindenengineering
12-13-2013, 02:05 AM
Just to add what Vic has posted.
An oil analysis is paramount to determine the amount of fuel dilution if the injection system is suspect. Also lubricating oil quality dilution etc (TBN number)

Also I see the oil jet cut away at the skirt has been diminished significantly, & cracked; Perhaps due to collision of the piston and the under piston oil spray jet at some time in its past! Maybe a clumsy install of the piston bending the jet? Consequently the piston is not cooled properly which shouldn't be overlooked especially if you are going to rebuild..

In any case each jet a has check valve, is it stuck closed for some reason?

If it is a fairly low mileage unit the jet may have distorted/defective prior to install on production. It happens!

When I rebuild these units they usually get new spray jet assys, (I take no prisoners, all go to the trash) but in any case prior to ANY assembly and following jet placement I take a 3/32" mig welding alum rod and place one in each jet which in effect will give you an aim of the jet as the welding rod pokes up through the block deck this in effect will be be a visual estimate of the oil jet wiping the crown underside as it rolls over TDC. Normally they are just off set to the thrust side but once you have all five in place they should all like up like a row of Grenadier Guards outside Buckingham Palace.

Best of luck with the job.
Dennis

MobileCC
12-13-2013, 09:22 PM
***wanted to add also this engine knock was intermittent and would go away sometimes ... it was most noticeable when the engine was hot and idling..while driving the noise would go away .. no smoke at all from the engine and had complete full power I noticed the engine oil was overfilled by at least 3 qts over the top fill line and the person drove several hundred miles with the intercooler hose that had a split in it