Camshaft and Gear Pressfit loosening
Posted: March 19th, 2015, 8:08 am
Hello guys,
I have a big problem back home. My car (K8) was running on the minimum oil level for a month while I was waiting to change it.
It started to knock very slightly and I wonder that it was the HLA starting to lose pressure. One week ago I changed the oil and the noise not only didn't vanish, but also started to increase.
On idle it was quiet, as soon as I rev it a little bit, it increased. The noise started to become very strong, as a hummer knock on the head, but very intermittent, gets quiet, increases a lot, gets quiet... . And some times the engine kills, and sounds as something locked it inside.
When the engine is hot, the starter can't start the engine. Looks like something is locking the engine.
When the engine is cold, it starts normally.
I decided to open one Camshaft Cover to take a look, and this is what I found. The synchro helical gear loosed his pressfit with the camshaft and moved axialy. What I imagine is that it is also rotating in relation to the camshaft, taking the engine out of the timing, and then coming back. That would explain the intermittent knocking noise.
I'm starting to think that something locked the left camshaft, and the axial forces of the helical contact made the gear slips aside. Maybe a hydro lock.
But the questions are:
- What would cause the gear to looses its pressfit?
- I could weld some small points to stick it together, but how the hell i'm going to set the synchro between the gear and the shafts again?
- What else could be damaged?
- The piston has contact with the valves in K8? That means. If the engine gets out of the timing, it's possible to piston to hit the valve?
I'm looking to disassemble the engine today.
I have a big problem back home. My car (K8) was running on the minimum oil level for a month while I was waiting to change it.
It started to knock very slightly and I wonder that it was the HLA starting to lose pressure. One week ago I changed the oil and the noise not only didn't vanish, but also started to increase.
On idle it was quiet, as soon as I rev it a little bit, it increased. The noise started to become very strong, as a hummer knock on the head, but very intermittent, gets quiet, increases a lot, gets quiet... . And some times the engine kills, and sounds as something locked it inside.
When the engine is hot, the starter can't start the engine. Looks like something is locking the engine.
When the engine is cold, it starts normally.
I decided to open one Camshaft Cover to take a look, and this is what I found. The synchro helical gear loosed his pressfit with the camshaft and moved axialy. What I imagine is that it is also rotating in relation to the camshaft, taking the engine out of the timing, and then coming back. That would explain the intermittent knocking noise.
I'm starting to think that something locked the left camshaft, and the axial forces of the helical contact made the gear slips aside. Maybe a hydro lock.
But the questions are:
- What would cause the gear to looses its pressfit?
- I could weld some small points to stick it together, but how the hell i'm going to set the synchro between the gear and the shafts again?
- What else could be damaged?
- The piston has contact with the valves in K8? That means. If the engine gets out of the timing, it's possible to piston to hit the valve?
I'm looking to disassemble the engine today.
