Engine Tips

At present, all information is tuned to the IO-540 installation only.  At present, I have not heard of anyone actually building an RV-10 using the Continental engine, and nearly all buyers are building RV-10's based on the IO-540.   This page, as the others, will grow as time goes on. All tips from other builders are greatly appreciated.

Cylinder Cooling Assistance

While at Land of Enchantment Fly-In I was reminded by Vic of something I heard regarding Aircraft cylinders.   Often, or most always when they're made, the 2 halves of the mold come together and leave a ridge of "flashing" where the cylinder halves met.   This flashing can restrict airflow through the cylinders.  The absolute worst place is right below your upper spark plugs.  Look down thru the fins and you'll see some narrow slots.  These are probably very restricted with flashing.   If you want to save your engine some trouble, ensure you have good airflow here by filing it out.

You need a really small file:   I found one for about  $3.50 (bought 2 of them) at the local farm store:

Nicholson 5 1/4" Tungsten Point File

This one is pretty tough, not too aggressive, and seems to work OK.   It will work, starting right off with the file, but I found a way to make it go faster for me...

I took one of my 12" #40 drill bits and put it in my dremel tool with the snake extension, set to fairly low speeds.  I ran  that drill into the slots and let it run horizontally back  and forth.  That chewed up a lot of the flashing, but left it  really jagged as it didn't smoothly cut it down in all areas. Then I could take the file to it and clean it up better.

Originally I started off with some areas and ends of the slots using a hacksaw blade too.  That worked well also to get them started.  I need to go over the ends of the slots though to avoid leaving square corners.

I also ran a  bead of RTV between the cylinders so prevent air from bypassing all of the fins, which was a suggestion another person at LOE, and added some additional RTV in certain areas to ensure no airflow was lost to leaks.

For more information and photos of this cylinder work, check this link to my page.   What you'll find there will be very enlightening if you're looking for help with cooling.  I've done some baffling work, and some cowl work and improved the cooling greatly.

Added 3/24/2007:  One huge improvement I got was by sealing my air ramps on the cowl inlets, as is discussed in this thread on Van's Air Force.


I did get a set of Louvers from Alex De Dominicis, who also does transition training, that he had with him at the LOE fly-in.  I'm currently thinking I will not install them though.  Alex said his CHT's dropped 25 degrees when he put them on, which is great, but I've also done some baffling work that has dropped my cooling significantly, so I'm not sure I want or need them.  Another RV-10 builder is installing them this week and will report back this weekend.  If he gets 25 degrees too, then they may very well be a good way for some people to drop their CHT's if their baffling can't be improved.

Microlon & Avblend

I've heard enough good about AvBlend to consider start using it on my next oil change.  For what it's worth, it sounds like I may be able to get very similar results with Marvels Mystery Oil, but AvBlend is FAA Approved.   Microlon is another one of  those products.  Vic used it on his RV-10 and he claimed significant cooling of his cylinders....to the tune of 30 degrees.  According to Aircraft Spruce, you order 1 full kit and one 1/2 kit to treat an IO-540.   I'm going to try that too, since it's also FAA Approved, but not until my next oil change.  Vic uses 2 cans of AvBlend at each oil change, so that's encouraging to know that he feels it gives results.  Be aware that if you read online, you can find very convincing arguments both for and against using any of these things in your engine.


Oil Quick-Drain and Hose Kit
One of the things I added to my engine was a quick-drain and hose kit for oil changes.  It makes it easy and no mess to change my oil, without removing the lower cowling.  Before purchase, I had read online threads regarding different quickdrains.  I couldn't believe how expensive some are, and how cheap others are, with no real difference in quality.   I decided to try this Curtis valve and hose kit from Aircraft Spruce.

05-01872 CURTIS DRAIN VALVES CCA-1700         11.65
05-00138 CCB-39600-1 BLK QUK DRAIN HOSE       10.80

Total cost, just over $22.50, and it works like a charm.  The hose snaps into place with a 1/4 turn, and you're draining the oil with no mess.  The only thing is, to change the oil hot, you want to wrap your hand in a cotton towl when working near the exhaust.  Or better yet, get an old oven mitt and keep it in the hanger.

Oil Leak Detection on the Engine
Since day 1, I had a small oil seepage from my engine on the right rear side. I tried to find it unsuccessfully, until I finally got serious about it and got myself a UV leak detection setup, consisting of UV Dye and a UV penlight.  Both are made by Supercool, and I got them at the local CarQuest store.  Total cost was $6/oz for the dye (2 oz required), and $24 for the UV penlight.  To see more about my leak detecting, read my maintenance post HERE.

LOP (Lean of Peak) Injector Tuning
See my write-up HERE of tuning injectors on the IO-540