My 0300D engine is about 75 hours away from its 1800 hr rebuild.
It had a complete new top end 300 hours ago (before I purchased it).
When I first bought the plane I had a partner and he stuck a valve that was replaced - 150 hours ago.
Since then I have owned it on my own. I run Avblend in the oil and I run one fuel sampling cup of synthetic 2 stroke oil per 18 Gal tank of gas, and all ground operations are performed VERY lean and I have had no problems - it is a VERY smooth engine.
I only use 1 litre of oil in 25 hours (I run straight weight 80 and 100 depending on season - not 20-50).
Compressions are excellent.
Question - it compressions and oil consumption are excellent what should I be doing at 1800 hrs?
Should I rebuild?
Should I keep going?
My insurance form always asks for hours to TBO.
If I don't rebuild am I going to have trouble reinsuring?
Irf I don't rebuild, does this sound like a safe option, or a risky option? I would appreciate some advice from members with more experience than my meagre 225 hours?
The manufactureres RECOMMENDED TBO is based on the fact that after a certain number of hours(in your case 1800) the engine starts to cost more to eventually overhaul than it should at their TBO.In most cases,(i repeat most) an insurance agency wont have a problem with insuring an aircraft over TBO provided that the last annual inspection found it airworthy.In essence,the longer you run an engine after TBO the more itll lilely cost you when you DO overhaul it.Id say as long as compression is within perameters,and its not making any metal let her bump,just be prepared to spend more on the overhaul the longer you run it over the TBO.....
what year was your last overhaul? an O-300D is 1800 or 12 years
what ever comes first, again its recomended. I just overhauled a
O300A for a customer and it wasnt touched since 1956. his case and crank was the only parts that made it. OH! it only had 1600 TT.
but way over T.B.O. I have seen some with 3000 hours and were good overhauls. If you have the money overhaul it and you should have several trouble free years, otherwise fly it until the first sign of metal.
It 's strictly your gamble. You do what you are comfortable with. If I was your passenger and you told me that, I would probably find another way home. If the manufacturer says they recommend an overhaul at a certain time, then, I go with that because I'm not doing the flying thing to be a test pilot.. Sure it's a factory recommendation, and whats wrong with that? Fly it and watch for metal? Yeaaaaaaaa Right!
I am not done yet..... what about the Magnetoes that may have dry internal bearings, distributers that are wobbleing in their bushings and other unknown nasties, Main, Rod bearings, and case halves that have taken the pounding from those big pistons being forced to change directions, The dried and rotted fuel and oil lines, the baffleing that is not creating the proper seal, the internal parts of the Carburetor. The Overhaul is much more than pistons, cylinders, and compression... It's the certification that "this aircraft has been determined to be in an airworthy condition" that would stick in my mind. Not- "if it isn't spitting parts, it's still ok"...
There are certainly a lot of old threads on this subject. You might want to do a search using TBO in the criteria.
I've only owned for 2 years now. My thouhts...
Fatory recommendations 1800 hours or 12 years are "probably" meant to account for all types of use. So it is worth considering how your plane was used over the TBO.
Use should make a difference.
If you have 1800 hours of half-hour average flights that will make a difference harder use more starting stopping cycles.
If a lot of training hours are involved.
Does the engine run hot? (do you know.)
Near the sea or very moist climate - and left outdoors
Was operated as a rental for much of the time
low time but long time between overhauls
Haven't a clue how it was operated before you owned it.
Long average flight times in steady-cruise
Cool engine temperatures
Many hours but short time between overhauls
my 2 cents
I used to own a 1966G Skyhawk with an O-300D engine. At about 1700 hours, I had all of the cylinders overhauled. The inside of the engine was inspected and I was told that things were in good shape, so I just put the cylinders back on. I ran the engine to 2020 hours then sold the airplane. Compressions were good as you would expect, and everything else was functioning well. If your engine is running well, then the tbo thing is only a guideline.
I have a '56 skyhawk with an O300 that has around 800 hours on a major that was done in 1969. It still runs strong and has good compression. The only thing I've had to do is replace one cylinder last year due to a crack. I have it looked at carefully each year during the annual and I will replace it in five years if it makes it with a Lycoming 180hp conversion. Now with that said, it it looks like it's going to give me fits due to safety or cost of on going maintenance then it is coming right off. I do not want to fly with anything that is unsafe.
As you can see,the general concensus it indeed to"let her bump" but you need to be aware that TBO is not just for Engine only,each accessory has its own tbo,and is stated by their respective manufacturers,from magnetos,to vacuum pump,Continentals stated TBO is for the engine only(which basically is cases,cylinders,crank cam lifter bodies etc)....tailwinds
> Tony . Not to get off the subject , but being a new owner I
> was curious about adding two stroke oil to the fuel as you
> mentioned.thanks Ed
Hi Ed. Please be aware that I am not a tech, that what I do may or may not be legal where you are and that I am referring specifically to the 0300 series Continental engine. This is a very contentious issue. When I found the plane that I was interested in buying I asked for advice on many internet groups, and also from several maintenance shops. I received a large number of replies from owners of similar models and from Techs who maintain this model of aircraft. I also did google searches and found many articles, plus I spoke with techs from local maintenance facilities, and I also looked up names of owners on the internet and then contacted them. I mention this so that you know this was not some whim - it was the result of hundreds of discussions and many hours of research.
Here is what I learned. The 0300 (in my case the 0300D) was made to run on 87 octane which is no longer available. Many of the pilots that I spoke to now run their 0300D's on Mogas, but several techs convinced me that I should not do this for several reasons. Some of those mentioned were that it gets vapour locks, it can freeze, it is more corrosive to rubber gaskets/seals/bladders, it is more prone to carb ice and several other reasons. Add to that that I cannot buy Mogas on my field, and I am not about to start carting cans of the stuff to the airport and refuelling by hand every time - I decided against it. The alternative was 100ll, but a lot of knowledgeable people told me that I would suffer from sticking valve problems if I run 100ll. This is due to buildups of gum, lead and carbon on the valve guides (also carbon on the plugs) - then one day the valve doesn't open all the way (usually exhaust) and you have a stuck valve. I was told, by owners and by techs that there were some things that I could do to make 100ll more reliable as the primary fuel for my engine.
Number one is, immediately upon startup, lean so aggressively that to apply full power would stall the engine. Keep it at that setting for all ground manouvers except the runup. On the runway go full rich for takeoff and lean about 100 lean of peak as soon as you reach cruise. After landing, lean aggressively and let the engine run a couple of minutes leaned to the edge of stalling prior to shutdown. This is to keep the plugs clean and burn any junk off the valve guides. Also - add Avblend to the oil every oil change, add a spin-on filter if you don't have one and change oil early - 40 hrs instead of 50. I was also advised not to run 20-50. I run 80 or 100 straight depending on season. Also add TCP to the gas - it scavenges the lead out of the gas. I cannot buy TCP here - 6 month backlog of orders. My tech told me that instead I should use one fuel sampling cup of synthetic 2 stroke oil (he recommended Arctic Cat as being the best). The valve guides are now being lubricated from both sides, and you are controlling the lead.
It is impossible to prove whether or not all of this works and is necessary, but I can tell you this. Some very reputable shops - Skyranch for example - religiously add Avblend. When I first bought my plane I was in a partnership with a guy who did not agree with what I was doing - but I always added my 2 stroke oil every time the plane was filled, and I would always run it leaned on the ground for longer, if he had been flying it before me.
then one weekend he took the plane on a long flight - refuelled twice without additive, didn't lean - and had to rent a car to come home - the plane was on the ground with a stuck valve. We had a disagreement about it, $650.00 later he was back to pickup the plane, still didn't add anything, didn't lean - landed at our home airport and taxied in (I was there) with a non-seating valve - I could hear it. I added oil to the gas, I started the plane and did a 10 minute runup VERY lean, then taxied to our runup area, did another full runup - still lean, then did a rich runup. All valve whistle had gone and I flew it for an hour. After landing we had a long chat and I bought out his share of the plane. That was 10 months ago and I have not had a valve problem since.
So - does it work? I don't know - but it sure as hell gives me confidence in my engine when flying.
I agree with the leaning, and adding Av-Blend, but what is the 2-stroke oil supposed to do? You mentioned scavenging lead--that is what TCP does. Are you saying the 2-stroke oil also does what TCP does? Av-blend can help free sticking valves because of it's molecular size getting into minute crevices that regular oil cannot (so says Av-blend).
> I agree with the leaning, and adding Av-Blend, but what is the
> 2-stroke oil supposed to do? You mentioned scavenging
> lead--that is what TCP does. Are you saying the 2-stroke oil
> also does what TCP does?
Please keep in mind that, not being technically minded myself, I went out to get these answers from others, and only after receiving solutions which were confirmed from several sources, including personal discussions with local techs, did I decide on my present course of action. Also, because I am not technical I am not the right person to be explaining why it works - however I'll try.
I cannot buy TCP here. My Tech, and others, told me that using the synthetic 2 stroke oil (one fuel sampler per full tank) would provide some lubrication to the valves, in addition to the lubrication that they received from the oil/Avblend. Everyone agreed that if I was running 100ll then I should be doing something to keep the lead down and provide some lubrication to the valves/guides. In the absence of TCP it was agreed that a combination of leaning and synthetic 2 stroke oil in the 100ll, together with avblend in straight weight oil was a good way to achieve the objective.
The reference to the lead scavenging is that the tech told me that I wouldn't need to add the 2 stroke oil if I was using TCP as the TCP would take care of some of the deposits - in particular lead - that accrue to the valves/valve guides. He also told me that even if I could buy TCP here that I am better using the synthetic 2 stroke oil because, quote, "TCP is extremely harmful to your health and also to your aircraft if you spill it or use it incorrectly".
That's about as much as I can tell you,
1) Lead is NOT a valve lubricant. Lead salts are not lubricants. They are abrasive. Lead does not (and never did) lubricate anything in an aircraft engine. That oldl wives' tale will not go away.
2) I have been unable to find any data which suggests that ANY of the oil additives do anything that using a certifed aviation oil and changing it frequently does not already do--other than waste your hard-earned money.
3) Adding oil to the fuel reduces the octane rating, which narrows the detonation margin, which if you are using auto fuel is already lower than 100LL. (although, admittedly, in the small quanitites you are discussing, it's unlikely to be much of a factor.)
4) Lead scavanging is for the purpose of reducing lead fouling on plugs that are too cool for the purpose and in engines not using the correct lead content in the fuel.
'Tis amazing all of the things which are assigned affects which are unfounded.
Advanced Pilot Seminars
<"I have been unable to find any data ... etc. ">
There is no data on lots of "remedies" that work for the people using them. If you tell someone that something shouldn't help, and there is no data saying that it does, but that person is still doing this with positive results.....it's kinda hard to argue with success. I had a problem with a valve sticking on a 0-235 and after adding Avblend, it quit sticking. Did the Avblend fix it? Or was it going to free itself up? No way to tell for sure, but it's kinda like the old health remedy of chicken soup for a cold...."it couldn't hurt".
Thanks for your response. I want to clarify a couple of my statements that you seem to have misunderstood.
>1) Lead is NOT a valve lubricant. Lead salts are not lubricants. They are abrasive. Lead does not (and never did) lubricate anything in an aircraft engine.
I agree totally - that is one of the reasons for using the oil.
> Adding oil to the fuel reduces the octane rating, which narrows >the detonation margin, which if you are using auto fuel is already >lower than 100LL.
I agree but I don't run auto fuel - I run 100ll - but only because I can't get 87 Octane avgas.
>Lead scavanging is for the purpose of reducing lead fouling on >plugs that are too cool for the purpose and in engines not using >the correct lead content in the fuel.
I agree but the 0300's don't use the correct lead content in the fuel. They were made for 87 Octane but now that is not available they are running 100ll.
I hope that this clarifies my previous comments.
Thanks for your response
Yes, it is difficult to prove a negative. BUT, it is also just as important to assign the correct cause for the observed result.
For example, it has been repeatedly stated that using unleaded auto fuel causes early valve failure because of the lack of lead.
This is not correct. It is correct that those engines seem to have earlier valve failures and more valve problems. Why? As it turns out, the probelm is NOT the lack of lead, but the increased internal cylinder pressures which result from using lower octane fuels with the same fixed timing as when 100LL is used. If the experiement is done adjusting for internal cylinder pressures, there is no difference in the stress on the valves from leaded and unleaded fuels. The lead make NO difference in valve life.
This is a case of a correct observation being labeled with the wrong cause. This happens a lot in aviation when we use nothing but anecdotal evidence and it oftentimes results in the establishment of an Old Wives' Tale.
Old wives' tales are like snakes... they take a lot of killin'.
Advanced Pilot Seminars
Back in the days of leaded farm fuel, occasionally, my dad would add a little diesel to our gasoline powered farm equipment. He said this would help clean up the valves. You could see a little difference. Too much diesel and you could really see the smoke too.
A lot of fuel additives use diesel or kerosene as a carrier for the chemical.
Would Diesel added to the fuel be better than adding oil to the fuel?
Have you ever used Kreen to clean up an engine?
I have used KREEN to clean up dirty engines. This stuff disolves carbon and gunk in the engine. From experience, I know that it will free up stuck rings.
KREEN is made by Kano Laboritories. They are the same people who make KROIL.
Here is some of the research that I did on Avblend:
MORE ON LYCOMING POWER PLANTS
by Jack Huffman, Technical Counselor, EAA Chapter 49
Most of the following I have plagiarized from past issues of Light Plane Maintenance: Lycoming Service Bulletin 522 (11-1-94) applies to 0-235 engines that have had pushrods replaced or maybe purchased between Feb. 22, 93 and September 2, 1994. Lycoming says that there had been several failures of pushrods. P/N 73806 as a result of scoring on the inside diameter of the pushrod tube. The scoring of the tube was introduced during extrusion of the tube during manufacture.
It is not possible to visually inspect the suspect tubes; apparently the only option is to replace any tubes with the above part numbers if they were obtained of installed between 2/93 and 9/94. Any pushrods marked “73806V” or “73806W” should be replaced immediately.
With so many ‘horror stories’ going around regarding sticking valves and questionable (especially in California) gasoline recipes, perhaps the following article from LPM, might be of interest:
It is with an extremely jaundiced eye that we tend to view oil additives. Thus, with a great skepticism did we journey to Illinois recently to look at a product called Linkite AvBlend. Sure, we thought here’s yet another snake-oil. During previous discussions with the Rachanskys (owners of Blueprint Engines, and purveyors of AvBlend) they offered us reams of testimonials. In all, it sounded like the same old song and dance. But we were surprised at what we found. Unlike any other oil additive we’ve ever looked at, the Rachanskys offered us actual independent lab test results. Not only that, but the test was a real industry standard. The test showed actual quantifiable results from using oil treated with AvBlend. We were impressed.
What added to our impression is the history behind AvBlend. It quickly became clear that this is no mixed-in-the-kitchen product that was cooked up recently. The lab tests, performed by the Armour Research Foundation of the Illinois Institute of Technology, were done back in 1951. The stack of testimonials, which normally would leave us cold, dates back to the 1940’s and includes such high-powered racing names as Bettenhausen and Fohr.
Of course the Rachanskys were quite happy to put on their own evidence. One of the more intriguing items was a set of cylinders from a Lycoming HIO-360 helicopter engine. These jugs had completed four TBO runs and retained their original dimensions using AvBlend. We miked the valves from these jugs and found them to show negligible wear. And the Rachanskys had the documentation from all the overhauls to back up their claims as to what we were looking at. Impressive.
One final factor that swayed us is the fact that AvBlend is FAA approved. Those are two words that you’ll be hard pressed to find printed on any other oil additive label. Normally we just don’t get excited about the words ‘FAA Approved’, if only because it has proved to be a rather hollow endorsement in so many cases. But in the case of AvBlend, FAA’s approval is based on not just some arbitrary test-cell run. The Agency reviewed years of service data from engines operating with AvBlend and the results of a 1,000 hour test run.
So, is this stuff a panacea? Does it spell the end of so many problems like ring or valve sticking? Probably not. However, from all that we’ve seen, it does offer some positive protection against such calamities. The Rachanskys tell us that their experience in tearing down engines that have run to TBO using AvBlend shows top end wear to be minimal, with ring lands and valve guides remaining largely crud-free. From parts we examined (none of which had been bead blasted or given any abrasive cleaning), their claim is true.
At long last, then, we’ve come across an oil additive that we can get behind. From the evidence presented, we feel confident that AvBlend will, indeed, do what it claims. In the wake of the demise of Mobile AV1, using AvBlend as an oil additive with whatever oil you choose is probably a good idea. And tossing in the prescribed amount of AvBlend is a good idea right from the start with your fresh overhaul. Top-End distress is probably the No.1 reason for premature major engine work, and while AvBlend may not be an absolute guarantee of trouble-free top-end life (let’s face it, nothing can do that, top ends being what they are), We’re convinced it can help to keep your top-end happy from zero SMOH to TBO plus.”
There are any number of places that sell this stuff. Do I use it? Yes. Does it do any good? Heck I don’t know - my engine hasn’t burned up yet. It is expensive; around $20.00 per treatment. Have you priced a major overhaul lately?
Custom Quality Aircraft Engine Rebuilders
Federal Aviation Administration Certified Repair Station # T7KR187Y
Textron Lycoming --Factory Trained Technicians--- Teledyne Continental
Hangar 1301 On Beautiful Palm Beach County Park Airport
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Tropic Airpower Overview
A "CUSTOM QUALITY ENGINE OVERHAUL" is not something that happens because we use the word "QUALITY". It is the process which through years of learning and applying known practice's produces an aircraft engine you can depend on. "QUALITY" in essence means: "NO SHORTCUTS!". At Tropic Airpower we wont allow you to get bit because of an inferior part or a shortcut method of rebuilding Your engine. We at Tropic Airpower are here for you, not because its a job, but because we love and respect aircraft engines. Our commitment is reflected into every engine we do. We custom rebuild engines to manufacture’s new limits specifications. Our goals are zero defects and maintaining our shop with the latest and best process's with technical information and schooling from the engine manufacture's and other leaders in the aircraft industry. We can pick up and deliver your engine within 100 miles free. Removal and installation of your engine is available. . . .
. . . . Cylinder flow matching is available. Crankcases and all internal parts are measured for New Limits specifications and Non Destructive Tested for Integrity. The Camshaft is Reground to new specifications. All New Lifters, Pistons, Rod Bolts, Bearings, all Gaskets/seals are among the numerous Touches we apply to each and every NEW LIMITS Custom Engine. High tech Powder coat paint is available for your Engines personalized colors. Every Engine is returned to the Customer with a can of AVBLEND FAA approved lubricant that soaks into metal and helps to prevent cold start damage and sticking valves to enhance engine life. A time proven product.
From Jabiru News
Have you considered bringing your engine to STA for servicing? The cost is not excessive and there is a major advantage in someone servicing the engine who is looking at Jabiru's all the time. Any upgrades required can be done at the same time for a minimal charge. The typical charge for a 50 hour service is £95 plus VAT and includes oil and filter.
Although the stated oil change period for air cooled aero engines is fifty hours, discussions with oil manufacturers at Oshkosh lead us to believe that twenty five hour period is much better for the engine
Avblend Oil Additive
We have been testing Avblend with a few local Jabiru engines based upon very good reports from Australia. During my recent visit I got to see an engine used by a flying school that had done 800 hours, there was hardly any wear and this was as a result of running with Avblend. This product is becoming very popular with engine overhaul companies in the USA as it is greatly extending engine life.
St Louis Flying Club
This is the first analysis we received since using Avblend and it seems to be working as the levels of wear metals in the oil sample (especially the chrome level) have dropped. Hopefully this trend will continue.
*Would Diesel added to the fuel be better than adding oil to the fuel?*
Both reduce the octane rating and therefore narrow the detonation margin. Aircraft engines are not at all like farm tractor engines in that the farm tractor engine is operated at a very low percent power rating. Not so with an aircraft engine which operates at high power settings by comparison.
*Have you ever used Kreen to clean up an engine?*
No. These additives wered designed to be used in engines running very ROP, where carbon buildup was/is a problem and the engines are not operated at high power outputs. They may well be a good idea and useful in that application but may not be a good idea at all in another application.
There is a MUCH better way to clean an aircraft engine. Run it LOP.
Advanced Pilot Seminars
I agree with runnning LOP to clean up an engine.
Jack, I have not used any of the "farm methods" in an aircraft engine. Not sure I would use the word scary, as long as these methods are not applied to a plane I am flying, but does cause one to scratch one's head.
Too bad LPG is not feasible for aircraft. No carbon. Oh, another farm method. lol
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