what could have caused this?

[chino12]

Originally Posted by ToKwik

Quick questions?

Did you verify there was no other damage? When that rod broke, it was because it was the weakest point when the failure occurred.

You stated that you replaced the crankshaft. Did you replace the bearings that were worn and clearanced for the old crank? Was the crank replaced because of a spun bearing?

If you are asking where TDC is for reassembly, then you may need to have someone else there who is more experienced take a look. I can probably think of a dozen things that could be wrong, but it's hard to make an educated guess on something you might have missed on your reassembly. For instance, what is the condition of the pistons? Are you reusing the old ones? Is the head on yet? What is the condition of the cylinders? Did you check them or just wipe the oil out with a rag? You replaced the rods, but what do the wrist pins look like? Are you using the old bearings, Bearings from the donor motor, Or did you purchase new ones?

I'm not trying to be an asshole, but you may need some assistance personally with reassembly. It is just a bunch of nuts and bolt, but there is a certain way it needs to go together in order for it to work properly. Finding help online may not be your best solution.

Hope you get it figured out.

thanks for the checklist dude, i do however like to fix my own stuff even though its my first time when dealing with an engine - worst case scenario i cannot fix it and buy a new one and lose a couple of euros, fuck that

i replaced the crankshaft because it was damaged where the rod which snapped is attached - dunno how its called

i didnt replace the bearings as they all looked the same and good to me

i am using a new set of pistons with a new set of rods - i didnt check the cylinders, just cleaned them and installed the pistons - they were sliding smooth when the rods were not attached to the shaft

so you are saying - judging by your answer - after the rods are installed and tightened the pistons should move when rotating the crankshaft?

quote from wikipedia

More generally, the dead centre is any position of a crank where the applied force is straight along its axis, meaning no turning force can be applied.