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Exhaust valve seat repalcement

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Exhaust valve seat repalcement

Postby Bil438 » Wed Jul 18, 2018 3:44 pm

I installed Jabiru 3300 s/n 331 in a Sonerai IILS. Found the #4 exhaust valve seat adrift and located on the valve like a hula hoop. I have photos if anyone wants them.
The head is removed and disassembled.
1. please send me the procedure to reinstall the seat
2. How can I prevent seat displacement again?
3. What would cause an exhaust valve to become adrift in the first place
Valve seat 331.jpg
Valve seat 331.jpg (93.01 KiB) Viewed 863 times
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Re: Exhaust valve seat repalcement

Postby Steevo » Wed Jul 18, 2018 5:23 pm

The valve seat is put in under heat. It’s not something you can easily do yourself.

There are only really 3 reasons that a seat can come out.

1) It breaks. Your one has not broken.
2) It was installed incorrectly in the first place.
3) The valve seat/head has been subjected to high temperatures. This could mean either your CHT or EGT on that head has gone above the maximum Jabiru recommended temperatures.

What are your average CHT and EGT readings?
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