Overhaul options and advise wanted.....

I want you guys to give me your two cents here please. My plane is a RV-4 that first flew in 2003. The engine on it was new in 1986 on a Cessna 172 and had about 1970 hours total time on it when the CAP pulled it off their Cessna and replaced it with a new one. This was back around 1999. It apparently sat in the hangar till 2003 when it flew again on the front of the RV - I didn't build the plane so I don't know all the details. The RV now has about 260 hours on the hobbs so add that to the 1970 hours the engine had on the cessna and it is now well past TBO.....

The engines logs are quite complete and show every oil change and adjustments ever made to it, and looking through I don't see any repairs made that I would consider major type repairs - such as new cylinders or anything internal - just rebuilds or replacements of things such as vacum pumps, or starters, mags, etc....

The builder of my plane did swap out the rear case so it would fit properly in the RV, and he installed a lightweight starter and alternator and that appears to be all he did to the engine to put it in the plane. Since then it has just had oil changes. Compression has been quite good, with readings of 70,71 and two at 75 at the last oil change and so far no metal has been found in the oil filter. The engine seems to be running very good overall.

I am considering overhaul because I know it will have to be done at some point, maybe sooner than later since I fly it quite a bit - over 110 hours since I bought it in March. So what I want opinions and advise on is my options.

What is my current engine worth as a core? I ask because a friend of mine is telling me to just buy a freshly overhauled engine - he says people on Barnstormers and Tradeaplane have them for sale from time to time - for 10-12 thousand, and he thinks I can sell my current engine as a core for 4-5 thousand.

Or what would it cost to overhaul it through a typical shop? Or if I did the removal from the plane and torn the engine down myself - I wouldn't know what parts are good or bad but should be able to take it apart, putting it back together I wouldn't trust myself to do right! -

What other options do I have??????

The same friend who I mentioned above has a little Acrosport Biplane for sale with a 150 hp O-320 in it that only has about 100 hours since major overhaul. He will sell me the whole plane for 18 thousand, possibly less... and even though my RV has a 160 HP version of the O-320, he thinks the engines could be swapped and I put the low time engine off the biplane on my RV and the high time engine off the RV on the acro, and then sell the Acrosport for 10 or 12 grand..... What about this idea? And IS it a easy swap - both engines have dynafocal mounts?? Will I really be able to tell the loss of 10 horsepower????

Lastly, one concern I have is trying to keep myself from having more into the plane than I can get back out of it. This RV is the most expensive thing I have ever owned other than my house.... I would not have bought such a expensive - for me - airplane had I not thought I could get most if not all my money back out of it at resale if that time ever came. The plane is well built, has a nice panel and one of the best looking paint jobs out there. Other than the high engine time, it is one of the nicest RV-4s I have seen. I paid just under 43 thousand to buy the plane, and not sure if I buy a new engine or pay a big shop to overhaul this one that I could afford to keep the plane afterwards, and really scared that I will end up with a plane worth much less than I have invested in it.... I know some people will say I should be more concerned about safety as a consideration for overhaul, but I don't feel this engine is all that tired with how good the compression is and how steady the oil pressure is, the lack of oil leaks and so on. I have heard of these engines going well over 3000 hours with no big troubles.

Anyway, sorry for the long post, and looking forwards to reading your replies.

Btw, I tried to attach a picture of it, but the forum won't take it for some reason....?

An axiom I have heard many times is: "If it ain't broke, don't fix it!"
In my opinion it applies here.
TBOs are suggestions from the manufacturer but are not required to be followed if you don't use your plane for hire, etc. etc.
I have run one engine past 2400 hours and finally did an OH due to oil leaks and oil usage. On high time engines, if everything is doing well in the cylinder department, you have to keep an eye on the bottom end. Oil pressure is critical...if you have good oil pressure, that is a very good sign. Keep a close eye on everything and have an A&P check it over to make sure there is no excessive play due to worn bearings, etc., and get his opinion as to what to monitor.
You may have a lot of hours still in that engine, but it is probably time to start planning. Flying frequently helps make your engine last longer, too.
I have done several OHs with the help of a local A&P and I think it is the way to go. You will be surprised how much you can learn and also how simple our little engines really are. It isn't really that difficult, but it is time consuming and you do need help to make sure it gets done correctly.
There are a lot of shops that do good OHs, but I don't have any personal experience with any of them. A factory reman would be my 2nd choice to doing my own.
If you move to 150 HP, you will notice a difference, especially with a FP prop, but you can put higher compression pistons in the 150 HO engine to get 160 HP. As far as changing out the engines, it should be straight forward as long as the accessory case and sump are the same. You could even switch those if you needed to.
But, I still say, don't fix it if it isn't broken!

Wobble test

Ron...

If you are going to keep flying it, take is to an A&P who can perform the Lycoming SB388 wobble test on the exhaust valves.

This checks for exhaust valves that are too loose in the guides - and likely to break the heads off - and for valves that are too tight (coked up) in their guides - and possible future stuck valves.

It's a fairly easy test, and if an high time engine fails, a valve failure can ruin your day quickly...

gil in Tucson

One option you might consider if you don't want to go to a constant speed prop is to order new cylinder assemblies from ECI (they have a five year warranty - best in the business) and buying new bearings from ECI. You can then do an overhaul to the engine core, sending off the case, crankshaft rocker arms, camshaft, etc. for overhaul and having the engine reassembled locally and you know what you have instead of buying a rebuilt engine that you really don't know anything about. You will need to get a local engine guy that knows his stuff to put the engine back together, not a shade tree mechanic. The local guy can also advise you what specific parts you should buy new for replacement and which are good to go with overhaul. You can also e-mail me direct dav1111 at cox.net and I can send you a list of parts I replaced new on my IO-540, and which I sent off for overhaul.

Many, many, rebuilders take parts from lots of different engines and rebuild. With a CAP first run engine that is running as good as yours seems to be I would much rather keep all the essentials of such engine (case, crank, cam) and add new cylinder assemblies, bearings, wear parts, and you essentelly have a new engine.

If you want to go with a constant speed prop you need to check and see if your engine can be adapted to a constant speed prop. A lot of O-320's won't take a CSP. My RV-6A O-320 wouldn't and I installed an AVIA veriable pitch prop what was great as it had it's own built in oil reservior to all pitch changes in the blade. It was really sweet for aerobatics.

Best regards,

Russ Daves
N-710RV (RV-10 on main gear)
N-65RV (RV-6A sold)

If you are going to keep going, SB 388B is a very good idea, as far as I am concerned. Putting it on 25 hour oil changes, filter inspections and compression checks would also be something I would do.
Some thing to watch out for is the nickel/dime effect. Don't keep dropping $$ into the engine at this stage of it's life, unless you can recoup those $$ at the overhaul. Many times someone will fix a couple of cylinders only to have another go bad 25 or 50 hours later. Don't get caught in that trap! Decide what you are willing to spend to keep it going, ahead off time, and STICK to the plan. If that plan says you aren't willing to spend anything, then when the low cylinder comes, don't get sucked in.
If overhaul is in the cards, you can certainly save some money doing it yourself, if you are capable and willing. If you are going to hire a company or a technician to do it, the price can vary greatly with what you are getting. So you will need to comparison shop before committing, to help make your decision.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts
are hopefully helpful to you. Please use the information provided
responsibly and at you own risk."

Thanks for the advise so far guys, very helpful!

How about some numbers on the overhaul? what will new cylinders cost? Why not send my current cylinders out to have them overhauled, and maybe chromed at that time as well?

Do I need new pistons at overhaul, or maybe just rings?

Would that wobble test SB be taken care of during the overhaul process?

The engine runs very well, doesn't leak any oil, doesn't burn much oil - If I don't do any aerobatics I believe it would use oil at a rate of one quart every 10 or so hours, but doing my sloopy loops and rolls and so on the oil useage seems to go up to a quart every 3-5 hours.

I probably won't ever put a constant speed prop on it. The plane performs fine without it, and it is a fair amount of money to buy one and it would seem a CS prop is just more things to go wrong or have to service.... Another pilot at my airport has a sweet RV-6 with the same engine as mine but his has the CS prop, his bird does get off the ground a tad sooner and climbs out with more authority for the first little bit but then I catch up to him and begin to outclimb him and then as we build up speed I blow his doors off for cruise or top speed. His plane also seems to glide like a rock when you pull the power to idle, something I didn't like....

So far I haven't spent any money on the engine other than expensive shell 15x50 mulity weight oil and champion filters..... If a cylinder went bad or something else like that, I would just go ahead and get the overhaul done. I am hoping to get another hundred - or three - hours out of it before I got to do anything major to it.

In case it matters, the engine is a lycoming O-320-D2J L-13809-39A

Keep the ideas and comments flowing people, I really appreciate it.