0-320 talk

[Av8torTom]

I thought this was rather useful

http://hoftec.blogspot.com/2007/08/w...20-really.html

[Mel]

Verify information before purchasing an engine based on this info. There are some discrepancies. For example, the second digit of the prefix being a "3" does not mean 7/16" prop bolts. The O-320-E3D uses 3/8" bolts.

[Snowflake]

I find the Wikipedia page (http://en.wikipedia.org/wiki/Lycoming_O-320) to be a much easier to follow breakdown of the O-320 models.

[avq]

I still find this information to be somewhat confusing.

I recently bought an engine "basket" with Lycoming O-320-Axx parts. I know the case serial number is -27 and it has straight mounts. This tells me I indeed have a -Axx engine. The crank is fixed pitch so this implies -A2x. My oil sump has a tapered riser so my engine must be an -A2A. The only discrepancy here is that my prop bolts are 7/16. This is where I get lost.

I am guessing I still have an -A2A with 7/16 prop bolts.

Any ideas?

P.S. I will be using slick mags...

[smokyray]

Anton,

You are correct sir. I have installed two straight mount "A" or "Dash Nothing" 0-320's in my RV4 and now my RVX. I salvaged them off an Apache many years ago. These engines were common in 1950's era Pipers like the Apache and the early Cherokees. The flange bolts do vary as the hollow crank engines have the 7/16 bolts and some solid crank engines have 3/8 although some were adapted over the years. It depended on which prop was certified for the installation. The lugs are removable and can be adjusted for your purposes. Saber MFG sells extensions with several options to match. Consider using an electronic ignition or P-Mag on one side, it easily gave me 3-5 HP and dropped my FF 1 GPH. The Rotec TBI works well on this engine too which makes it Mogas capable.

Built correctly they are great little engines, lighter than a wide deck 0-320 and can be bought very reasonably. Their only drawback is the case through bolts aren't strong enough to upgrade to the 8.5:1 pistons to make it 160HP. In the 0-320A, the stock was 7.4:1. The local airboat boys run an aftermarket forged TRW racing piston that is 8.0:1, I run the same pistons in mine. I am running all aftermarket airboat racing parts except my crank and cam which are yellow tagged. Good Luck!

Smokey
HR2
RVX

[N941WR]

Originally Posted by avq

I still find this information to be somewhat confusing.

I recently bought an engine "basket" with Lycoming O-320-Axx parts. I know the case serial number is -27 and it has straight mounts. ...

Any ideas?

P.S. I will be using slick mags...

FYI - One of my friends bought an O-320-??? from this board. It was a former A&P school training aid and advertised as such.

Since everything had to be inspected, he had the straight (Conical) mounts converted to Dynafocal 1's when they re-worked the case. IIRC he said it only cost him $200 additional but had to be done with the engine disassembled.

Here's a link.

[avq]

Bill, Smokey,

Thanks for your inputs. All of my critical engine components are currently being reworked and inspected. I did not think about converting my conical to dyno 1 since Vans sells conical mounts for the 7. I actually already received the case back yellow tagged and I added cam oiler nozzles. I figure the nozzles + pre-oiler + heat will help prevent cam rust which I just recently experience in my Cherokee. (I do understand flying is to best prevention)

Thanks for your recommendation on the P-mag. I will need to do more research on the subject since I have not considered it.

The Rotec TBI looks enticing but I like the price of the 38mm Aerocarb from Aeroconversion. The aerocarb is also a TBI. I have found it difficult to compare performance between the two on paper.

I also thought about using different pistons to upgrade HP. I am leaning towards flying at 150 HP first then upgrading later.

Thanks again for your comments!