Rave Valve cap melted???

[FULL-THROTTLE]

Happy holidays to all,

1998 Challenger w/twin787's

I have a brand new 787 with 2 tanks of fuel through it, I opened the engine compartment and the plastic cap of one of the rave valves is 50% melted,
I pulled the cap off and every thing seems OK, I unscrewed the plastic cap (where the spring sits on) and the rave valve moves freely?????????????

Any thoughts on this??

SBT wants me to pull the engine and send it back, but that s*cks for me, I don't understand what happened or where the heat came from.

Thanks

 

[nswillin]

Re Post?

I think you posted on this problem in Nov sometime and you had no follow up on what happened. The advise I gave you was the melted rave valve cap is due to the valve housing or o ring being worn. Once that happens the exhaust gas will follow up the shaft on the rave valve itself and melt the cap. Remove the whole assembly and see how much play there is between the rave valve housing and shaft. I would get a rave valve rebuild kit and it should take care of it or replace the entire housing.

 

[FULL-THROTTLE]

Thanks

Thanks for the heads up, I really hate to pull the entire engine for such a small issue.

I plan on pulling the valve assy and hopefully it is just a minor o-ring.

Thank Again,

 

[kustomkarl]

Uh...there is no reason to pull the engine to check the rave valve...

:ack:

Karl

 

[FULL-THROTTLE]

Update

I have been away with the military so I am just getting back to dealing with the RAVE vale issue,

The motor is brand new from SBT, if I pull the rave valve assy I viod my warranty, they want me to pull the motor and send it back for a new motor.

I just took a look at the valve and this is what I found, with all the plastic, spring and whats left of the cover removed I can freely move the Rave valve up and down, there is some play laterally with the valve, more than the other 3 rave valves(twin 787's), ???

Any thoughts would be appreciated.

PS: SBT will send a new RAVE Valve assembly but their concern is the clearance in the head where the valve slides is too great and this is causing to much exhaust to travel up into the bellows and the extra heat is melting everything.

I tried to attach some pics,

Thanks,

Fran

 

[kustomkarl]

SBT is correct...send the whole engine back...

Karl

 

[FULL-THROTTLE]

Thanks

Karl,

Thanks for the input, I really don't want to pull the motor, but I want it working correctly for the summer.

Time to go work.

Thanks again,


Fran

 

[scooper77515]

Not sure if this has anything to do with anything here...

But mine did that over and over, with new parts, new o-rings, new retaining springs, etc.

I rebuilt and replaced the entire rave assembly, all the plastic, rubber and springs, and one of the actual valves.

I could never figure out why this was happening, and then I shattered a piston wrist pin and threw a rod on the cylinder that was giving me the most melting problems.

Might have been coincidence, maybe not.

So send the motor back and let the experts deal with it, and hopefully you won't be having to shop for a new motor anytime soon.

By the way, the new motor I put in has had none of these melting issues.

I can't help but think that the melted raves was either caused by, or somehow caused, or at least was warning about the impending engine failure.

 

[FULL-THROTTLE]

Update

I just pulled the motor and I found both pistons and cylinders severely scuffed/scratched and both rings on each piston look like they are stuck.

The engine had a full tank of premix 25:1 with the oil pump operating and the throttle never went above 1/2 throttle, I ran it for 20 mins and let it cool for 30 mins for the entire tank. then with the second tank I did not stay at full throttle very long. I only went through 1/2 of the second tank when I found the rave cap melted, and now bad pistons and cylinders.
I confirmed the oil pump is working when the engine was running by pullling the oil line going into the intake and I could see the oil pulsing/pumping.

What the heck is up with this engine, it only has 6 hours on it.

any help is appreciated.

 

[nswillin]

When you send the engine back to SBT they will tell why it has seized. Good luck man. :cheers: