[Don]

Van's is offering, for a limited time, an "inexpensive" O-320 for $20,900 (fixed pitch only). I'm comparing this to Penn Yan Aero's LX-O-320 for 21,850 (fixed pitch). Both appear to have the same accessories (2 Slick magnetos, harness, carb, and lightweight starter) and the same 2000 hour TBO. The Penn Yan Aero engine has the camshaft roller lifters.

I'm building a 9A and am about ready to order the "finish kit" (which is about as much of a misnomer as the word inexpensive is in O-320 advertisement - but I digress) and I need to make some decisions. I plan to use a Catto prop so I'm not concerned about the difference between a 25 and 40 hour Phase I program.

I see three possible advantages to the Penn Yan engine - one is there's no rush buying it. Van only has a few inexpensive engines left and I need to act fairly soon. My reputation for holding on to my money may rival Van's but I'm not nearly as well known as Van. Tomorrow's buck always seems to be worth less than todays - but the difference in this case is likely nearly meaningless. Second, the Penn Yan has the roller bearings. I have no idea if these are worth an extra $950. Penn Yan suggests they reduce cam shaft spalling, especially on a dry start of if there's corrosion. My question is how much difference? Third, the Penn Yan has some options available that look interesting, such as "port, polish and flow match" for $800 and add 10HP (I'm not interested in debating how many HP to put in an RV-9 ), a piston cooling oil nozzle kit and electronic ignition.

I'm not an engine guru but both engines, barring FAA considerations, look nearly equal in terms of reliability with a possible edge going to the Penn Yan Aero. I'd like to hear opinions, especially from folks with experience and those that know engines.

Don

 

[RV6_flyer]

Don:

The O-320 in my RV-6 has 5,100 hours since new and 1,891,1 since overhaul to new specs. I kind of like the roller cam. In theory, it should be better but it is NEW to aircraft engines. Superior has it as an option and now Lycoming has it as standard. I want to re-engine my airplane to a 360 but do not have CASH to pay for it. I WANT a roller cam. Last I looked, the roller cam was $2,150 option from Superior.

The other options will make the engine smoother and may make it last longer. All subjective. Yes all that stuff is done on my engine at a higher price that you are being charged. I do not believe that it adds more horsepower unless you want to turn more than 2,700 RPM. It does make the engine as good as it can be but you must deceide if it is worth the extra money.

Note how may hours are on my engine without roller cam technology. Not sure if it is worth extra money for the roller cam but I will pay for it if I install a 180 becasue I want it.

 

[gmcjetpilot]

15 hours

Don't worry about the 25 or 40 hours Phase I. I am not sure what model of O-320 van is selling (you say D2A? PA-28S Piper engine). Regardless you are using a experimental prop anyway which needs the 40 hours. Besides 40 hours is really what you need to get things sorted out. 15 hour difference is not a big deal and gives you time to develop performance charts and so on.

Don, comments are excellent. I can tell you about regular flat tappet hydraulic lifter cams. As you know the cam is splash lubricated which is OK of you fly a lot. Later cases or older cases can be modified with oil nozzles to provide more oil to the cam, but what kills cams is dis-use. However what it you don't fly a lot or frequently.

Now for the roller cam? If that would improve the reliability and reduce the chance of corrosion related problems than great. However I don't know that is true. Depending on you part of the country, corrosion in the engine can start in just days.

That first few seconds after start really kills the cam if the engine has been sitting. The oil drys up if it sits; the cam is "wet-ted". So the roller cam should have less wear in the start-up. However if you fly often (a couple times a week) than it's not a big deal. The cam receives adiquate lubrication. If you are in the habit of going off for weeks with out flying or long periods of down time due to weather, than the roller cam should provide lower wear.

May I suggest you call Lycoming and ask their customer service department. They are very knowledgeable and can tell you the advantage of the roller cam. I know from my Hot Rod days roller cams release a little more HP and allow more radical cam profiles. Other than that I am not sure the price justifies it. I do know race cars can have roller cam issues like cam walk and so on. As Don said it is new technology (well old technology new application).

Last comment. IF YOU ARE NOT READY TO FLY SOON, say in the next year for sure, than it's too early for the engine. You should have everything done and the firewall mount and some accessories amounted before getting the engine in my opinion. There is no need leaving a +$20K engine sitting around.

 

[Joey]

O-320's seem to last forever anyway. In my opinion, the use of roller tappets to "cure" camshaft galling in an O-320 is a solution in search of a problem. I would get the cheaper engine and put the $900 towards fuel.

 

[mahlon_r]

The Vans deal is extremely attractive! I don't think you will see any practical difference in performance, operation or longevity with the roller tappets unless your aircraft is destined to be a hangar queen and won't fly at least an hour a week on a regular basis. If that is the case, and inactivity may be a factor at some point in the engines life, in my opinion, you may see more longevity with roller tappets over sliding tappets. Only time will tell for sure, if the roller tappets are a good fix, and haven't introduced any new issues. The roller tappets were put in place as a fix for the cam spalling issues sometimes seen with standard tappet engines, no other performance or operation gains were engineered in, that I am aware of and none that I have seen in the test cell.
If the port and polish option is really producing significantly more power, then I wouldn't do it. To get that kind of power increase means significant change to the ports, which might weaken them. If it were mine, I wouldn't take the chance of cracked cylinders down the road.
Good Luck,
Mahlon

 

[Brian Vickers]

I specifically asked Jeff Tyler at Penn Yan about the port flow match and polish option. He said the bottom line is that fuel consumption will go up. As he said, "You don't get something for nothing." You might want to talk with Jeff, or someone at Penn Yan. I was favorably impressed.