Valve Size

BillTIZ

BillTIZ

Final Approach
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Ok, we are trying to figure out the TBO for our engine. Turns out it depends on exhaust valve size.

Lyc O-540-B2C2 (from memory) 235HP
The LYC books say 1200hrs or 2000hrs depending on exhaust valve shaft diameter.

We were increasing our insured value this spring, and the insurance company held down the requested value based on an engine over TBO. They are thinking 1200hr TBO.

At last overhaul we added STC SE1433GL which upped the HP to 250.

The parts list for the engine shows the exhaust valve as part number 19001.
Lyc, ECI and Superior all have variations of the 19001, but no dimension data.

Any ideas?

Our next step is to contact the overhaul shop. He was mentioned in the last AOPA Mag article on engines.

We have 1480 hrs since overhaul, running strong and looks like 2000hrs is in reach. We average 150 hrs per year. So we are about 3.3 yrs from reaching 2000hrs.

It would be nice to have the documentation that it is a 2000hr TBO, just I case we have a claim.
 
BillTIZ said:
Ok, we are trying to figure out the TBO for our engine. Turns out it depends on exhaust valve size.

Lyc O-540-B2C2 (from memory) 235HP
The LYC books say 1200hrs or 2000hrs depending on exhaust valve shaft diameter.

We were increasing our insured value this spring, and the insurance company held down the requested value based on an engine over TBO. They are thinking 1200hr TBO.

At last overhaul we added STC SE1433GL which upped the HP to 250.

The parts list for the engine shows the exhaust valve as part number 19001.
Lyc, ECI and Superior all have variations of the 19001, but no dimension data.

Any ideas?

Our next step is to contact the overhaul shop. He was mentioned in the last AOPA Mag article on engines.

We have 1480 hrs since overhaul, running strong and looks like 2000hrs is in reach. We average 150 hrs per year. So we are about 3.3 yrs from reaching 2000hrs.

It would be nice to have the documentation that it is a 2000hr TBO, just I case we have a claim.
Click to expand...

I thought all Lyc's had a 1/2".../ .500" valve stem size and sodium cooled too...
 
Last edited:
N801BH said:
I thought all Lyc's had a 1/2"... .500 valve stem size and sodium cooled too...
Click to expand...

Lyc Service Instruction 1009AU, Nov 18, 2009

O-540-A, -B, 2000 hrs see Note 1, 10
Note 1, only engines with 1/2in Dia exhaust valves have 2000hr TBO.
Engines of this series with 7/16 in Dia exhaust valves should not exceed 1200 hrs TBO.
 
You could pull a rocker cover and measure it.
 
Unless you have an old engine that hasn't flown you probably have the 1/2 in valves.years ago I asked the same question and the mechanic could tell right away.Also check the logs.
 
Thanks all. I believe it is the 1/2", just need proof for the insurance company if it ever comes up that we have an over TBO engine.

It was last overhauled in 2003 (?) or so and has 1480 hrs since then.

Thanks Charlie, Ron and Steve.
 
BillTIZ said:
"Page cannot be found" at least not on the iPad. Can you retrieve and PM the attached file if it is not too large? If it is, let me know and I'll send you my home email via PM. thanks!
Click to expand...

Attached to previous post. Not sure why the original link didn't work. Re-entered that, also, and it appears to work for me.
 
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