S

skypilotusa

I'm New Here
I am building a O-360-A1A for my RV-7A.
My original core was ready for overhaul, so when I torn it down I noticed one of the main journals were cracked, so I decided to just replace the case with a tagged overhauled case. When I received the case it had a -27A designation, instead of the -36A I was expecting... I am at the understanding the -27A is a O-320 E2D case... but the case had the long one piece front main bearing, I thought E2D had the short 2 piece front main bearings...

Please help... are their some expert engine folks that can educate me.

Standing by

Sky
 
case

Dash 27A can be one of several 0 320 cases. I have a -27A case that is for the long bearing. Most -27A cases are for the short 0 235 bearings. As far as I can determine, the only way to be sure is to check with Lycoming or the overhaul facility that last certified the case.
 
skypilotusa said:
I am building a O-360-A1A for my RV-7A.
My original core was ready for overhaul, so when I torn it down I noticed one of the main journals were cracked, so I decided to just replace the case with a tagged overhauled case. When I received the case it had a -27A designation, instead of the -36A I was expecting... I am at the understanding the -27A is a O-320 E2D case... but the case had the long one piece front main bearing, I thought E2D had the short 2 piece front main bearings...

Please help... are their some expert engine folks that can educate me.

Standing by

Sky
Click to expand...

For sure money is an issue with a lot of builders and so is the compulsion to do everything yourself, but after touring the BAF shop in Tulsa several times while my engine was being built, there's no way I want to do that kind of work myself.

The equipment and experience in doing such a task properly is well worth the cost.
 
Update

OK...

I contacted Chuck Ney in Tulsa, OK... who re-worked the case.
Chuck has been doing these cases for years, and was extremely nice about explaining the whole process.

The O-320/360 are casted under the exact same number (72081/2 castings).
The difference is in how they are machined. This type of conversion is not unusual from what I understood. Chuck has been doing high performance case work forever and owns a few STC's... The case has the "Ney" nozzle mod that sprays oil directly on the CAM... not to be mistaken for piston nozzles...

Of course, as anal as I am... I contacted Lycoming and explained my concerns and they verified the casting numbers, and confirmed that this is a typical upgrade in the field and had no issues with it. I also had them walk me through the process of making sure the serial number matched the original data plate. Since we went from a narrow deck to a wide deck we will have to make sure we have the -36A designation... Lycoming is tracing the original -27A serial number and will forward me the history of the case as they know it.

I am satisfied with my investigation... The case looks like new... :)
 
Thanks

Thanks for all the replies...
I have been an A&P for about 25 years and have built my share of engines over the years... but was never confronted with having to actually replace the case.
I really enjoyed the learning experience over the past few days... lots of research and lots of numbers, always enjoyed the process.

Thanks folks!!

Sky
RV-7A
ATP, CFII, MEI, A&P
 
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