Rave valve hit piston

[gregvega]

I have a 2004 GTI LE RFI that the rave valve hit the piston. Upon tear down of top end found rave valve hit piston on bottom ring land. No ring left on piston. Cylinder walls, piston top and head chamber show no peppering or any real sign of damage from ring being hit. This engine was rebuilt 4 years ago and no more than 40hrs, it was bored one size over I believe.
We will try to inspect more of rave valve as to why it hit. I have a few questions.

1.Since the ring is gone, where did the bits go? Maybe rebuilder didn't put bottom ring on, I don't know.
2.Why would rave valve hit piston?
3.If ring did get knocked off, is the bottom end ok?
4. How far can the cylinder jug be bored out?


Anyone have any ideas?

Thanks

 

[mikidymac]

There is no way the ring is gone with no damage unless it was never installed.

The only way the RAVE valve could hit the piston is if the valve stem broke and it dropped down or the cylinder was bored and the RAVE valve was not trimmed for clearance.

 

[Lothsahn]

I have a 2004 GTI LE RFI that the rave valve hit the piston. Upon tear down of top end found rave valve hit piston on bottom ring land. No ring left on piston. Cylinder walls, piston top and head chamber show no peppering or any real sign of damage from ring being hit. This engine was rebuilt 4 years ago and no more than 40hrs, it was bored one size over I believe.
We will try to inspect more of rave valve as to why it hit. I have a few questions.

1.Since the ring is gone, where did the bits go? Maybe rebuilder didn't put bottom ring on, I don't know.
2.Why would rave valve hit piston?
3.If ring did get knocked off, is the bottom end ok?
4. How far can the cylinder jug be bored out?


Anyone have any ideas?

Thanks

2. The Rave valve's direction matters. If you reverse it 180 degrees, I believe it can and will impact the piston. You have to make sure it goes in the correct orientation. You can see a number of posts on this forum of the proper orientation of the rave valves. I suspect your valve was inserted backwards. Did you recently clean it? If it was backwards, I don't expect it would have run for 40 hours in that position.

Also, you said your cylinder was bored during the rebuild. If it's more than a certain amount over, the rave valve must be ground to the correct clearance.

Don't know the answers to the other questions.

 

[gregvega]

When the engine was rebuilt the shop had the rave valve to size it for the over bore. Weather they did I don't know, I'll have to check clearance. The rave valve housing only will mount one way on cylinder jug and rave valve blade will only go one way in housing, impossible to put in wrong. The blades were gummed up pretty bad, didn't have many hours on it. It has had the good synthetic Sea Doo oil its whole life.

 

[tobytd]

Your one-way theory on the housing and valve may be true of newer stuff. Older housings will mount either way, but will only function if installed with ‘ports aligned correctly. Older Guillotines will install in housings either way.

 

[tobytd]

Just did some digging, your RFI housing and guillotine will only mount one way.