head coming off again

[Andre Steyn]

As for metal shaving I cannot find anything, I remember even checking the first 2000km oil change oil for any metal bits with a magnet and running it through a sif, it was actually still reasonably clean! I actually kept the oil!

[ricster]

I'm thinking that the shavings will have worn away to nothing by now, and only the evidence is left. the oil suirters were probably not fully blocked, but maybe the oil stream was only hitting the underside of the piston when the piston was at its lowest point, so not a good drenching of oil throughout its travel path. There is then lubrication but just not a good constant supply of it. The marks are all on the same side ..... oil stream may be interrupted by the gudgeon pin when on its travel path and creating a "dry spot" on all the same areas of the sleeve. There may have been enough oil to prevent a sieze, but not enough to properly lubricate the whole area properly. Again, I'm just trying to find possibilities as to why it happened....

As Barry Roux says.... I put it to you..... Not as a fact, but for the purposes of understanding.....

[Andre Steyn]

Barry Roux "I put it to you this is a serious case" whahahahaha!!!!!! Take note of white residue in the green circles, this was under the head gasket and the precomp chambers.

[ricster]

What antifreeze did you use, cause looking at those water ports, it looks like HUGE buildup of lime or what ever they call that stuff, especially on both water ports between no 4 and no 5 cylinders. Between 3 & 4 looks much better, but the right ( exhaust side ) water port on no 6 cylinder also looks different to the left side.... Can't really see the others

Those marks could be from the head gasket failure where water sat in that tiny cavity between head - head gasket- block. The precom sits half in the cylinder void and half resting on the head gasket. The top of the sleeves are clean so contact was made between precom and head gasket and then sleeve top. I assume the torquing wasn't quite at the sweet spot, and a bit of water got there dried left that calcium or lime, then the process was repeated every time the motor was working and there was a gradual buildup over time. Probably just enough toque to prevent water squeezing into the oil ports.

[Andre Steyn]

I used ps23 premix antifreeze. I agree on the torque cos it was the old head bolts. The interesting thing is all the scoring marks are right down from where the white residue is built up, do you think they're connected? How can I get rid of all the scale buildup?

[ricster]

I was thinking exactly the same thing !!.... but how can it score the block. Using Barry Roux's analogy.... I put it to you..... that the evidence of water is not present on the sleeve tops. However it is possible I would think, and maybe as oil and water don't mix, that there was a tiny amount of water leaking into the cylinder and getting onto the ring. If the top ring "split" is at that point the tiny amount of water will probably be held there with the assistance of the thin oil film ( water "ball" will sit on top of the water)

Better demonstrated with this....

WATER RING.jpg (134.6 KiB) Viewed 1599 times

Maybe the same stuff thats in the water ports, was sitting on the rings, making a scouring paste ( like Vim kitchen cleaner ) and that with the lack of oil on the bores in that area due to there being water cleaning the oil film off the bores made the marks....... Holy smoke, it seems like I'm gaaning aan about things that are impossible.... but hey stranger thing have happened, and is it coincidence that it is right below the precoms.....

[ricster]

Cleaning that shhhhh...... rubbish out the cooling system??..... Not sure. You could acid wash the block I presume. I would think that that will clean it out. Must just wash the block 100% afterwards. Maybe someone can assist here or Google

[tour de frans]

Goeie Dag Almal
Hier is wat ek dink met Andre se engine gebeur het.
Dis nie fueling nie, of boost probleme nie. Te min fuel kom die engine nie weg nie ,en te veel fuel raak die ontbranding temp hoer en hy trek beter ens...
Ek dink dis coke wat opbou tussen die piston en boor tot by die boonste ring. Daai coke is hard en polish die boor. Dit lyk soos skrape. Die skrape is ook net aan die teenoorgestelde kant van die thrust kant. Die thrust kant werk harder en die coke kan nie die boor geskraap kry nie, die oorkant is wel wat die piston teen druk met kompressie slag. Daai drukking is hooggenoeg om die boor te skraap maar te min om die ring hard genoeg teen die boor te hou om die coke weg te vee.
As daai engine keystone ringe in het sal die coke build -up die so maklik wees nie. Die ringe skop oop onder vrag en seel beter teen die boor, met die kan die coke nie die boor skraap nie.
Die ander manier om dit te voorkom is om net die piston knoon 0.4 van n mm in totaal kleiner te maak. Maw die piston to bore bly 4 thou. Die kleiner piston kop sal die piston to bore op daai plek groter wees. Dit sal veroorsaak die coke sal nie saampak nie en loskom en uit brand.
Ek het so n soorgelyke probleem met Cummins uitgelig en die saak vir my werk gewen.
Hoop dit maak sin\. Ek se weer dis my mening, en het dit nie gelees of gehoor nie.
Groete

[Peter Connan]

Thus, the marks are made as the pistons move up, compressing the mixture before ignition.

I am wondering if there is a mismatch between the rings and the bores (that the rings are too hard or too soft for the bores)? I don't know if this is possible, whether there are different rings for different bores?

Andre, I am probably notorious for my views on engine mods in general and turbos in particular, but be very careful here. Some of the engines they have in Auz have much bigger crank journals etc. than most of the engines we have here, and other design features as well that are much better suited to high-boost applications.

My feeling is, if you want power, swop it for a 4.8. If you want reliabaility and feul economy, keep the boost low...

Eish, i must have been smoking some good stuff in my socks when i wrote this. Got my directions wrong. It's happening during the power stroke.

Have the white powder analised by a lab, shouldn't cost you much. If you still have it, do the same to the oil that came out.This can tell you a lot...

[Peter Connan]

Funny thing after reading Frans's reply: I remember looking at the carbon build-up at the tops of the bores in the first pics and thinking surely that was too much for such a short period?