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Engine Overhaul woes

Helmetfire

FRIEND
Caldwell, Texas
I bought my '54 Super Cub back in Oct of last year. Purchase was contingent on a fresh annual that returned some minor airframe discrepancies that were addressed accordingly. After the annual the owner asked if I wanted him to test fly the plane after inspection, he still owned the plane so I agreed of course. During that flight the engine started to run rough. Got it back down, started tearing into the engine only to find out on cylinder was bad. Then they looked closer at the bottom end and realized that the engine needed to be overhauled. The seller and i re-negotiated the price of the plane to reflect the cost of an overhaul. The mechanic claimed he's been rebuilding engines for 50 years, so I decided to trust him and give the guy my business...the airplane was already torn apart in his hangar, so it saved me a bunch of hassle hauling engine parts all over the countryside...(his place is a 2 hour drive from where I live).

The day fianally came where the plane was ready to run. The first break-in flight lasted about 30 mins and for the most part went well. The plane seemed to have excess vibrations but I was a greenhorn cub pilot, so I really wasn't sure what "normal" felt like yet. Plus, the prop had been dynamically balanced prior to the overhaul, and the mech said he didn't mark the prop orientation prior to removal and took all original balance weights off anyway. Tried to fly it home that day but spent an hour flying in some shitty rainy weather trying to make it over the mountains, and couldn't make it home. Eventually got the plane home a few days later.

I was never happy with the engine. It seemed to run well and made good power, but vibrated more than i thought should. Also burned very little oil, and the oil was staying pretty clean. For a while I thought it was the Sensenich prop causing the vibration, seems I always read on here how bad the Sensenich prop was for vibration. Had the prop dynamically balanced, no change. Had the prop checked out by a prop shop, no change. Tried a different prop same model, no change. Each time I'm trying to convince myself that things are improving, but really they weren't. Bought a brand new Borer prop that everyone swears is smoother than the Sensenich. This time I could tell that the prop was running smoother, but since it was so smooth, it really highlighted the engine vibration....managed to accrue 29 hours SOH on the engine during this time.

Next, I went through the trouble of swapping out the entire engine to see what that would feel like. The other engine ran fine with none of the vibrations that I was experiencing with mine...and that was a 1800 hr. engine had been sitting in a hangar for 15 years, not even pickled!! At that point I knew something was wrong with mine and sent it back to the engine guy. He tore the cylinders off and found scoring on all 4 cylinder walls, really bad scoring on one. He told me that he thought the ring gaps weren't right and that they were expanding too much and scraping the cylinder walls...whatever.

Cylinders were then sent for evaluation by ECI and they determined that it was FOD damage not related to the cylinders, so they won't be covered under warranty. They found: "Foreign object debris damage on piston domes. The damaged spots were up to a 1/4 inch across and .015" deep. The piston skirts also were scuffed, 1 piston had a bent oil control ring and a broken peice of ring land that fell out of the piston after removal"

"Cylinders and pistons were damaged by FOD. The debris was resilient enough to break through the anodized coating on the piston dome. The FOD was not aluminum. The FOD did not come from the cylinders"

"Recommendations-No reason for warranty consideration. Work needed to return to service: Replace all parts, seat guides, piston, valve train. Hone Bore, but it may not clean up"

This is just the cylinders. The bottom end will need new bearings, cam and crank polishing, etc.

Before I learned all this, I had sent them the results from the oil sample from the second oil change (hours 10-25) and it was clean. I took the engine off 3 hours after that oil change and they are claiming that all of this happend during the last 3 hours...of course the engine guy agrees with them so he won't be liable for damages...hes trying to tell me I dropped a washer in the plug hole or something...The only thing i did was install brand new plugs at 10 hours after I realized he put my old plugs back in the engine after overhaul. ( they weren't in that bad of shape but c'mon) I am beyond pissed and I don't know what to do next.

A few things I noticed sometime between all this. In looking at the logs prior to purchase, the engine log stated that this was an "O-320 A2B" engine. i didn't think much of it since that was a common engine model for cubs and never looked at the data plate (stupid me). He overhauled it thinking it was an A2B because thats what the logs said, and even put that in the log entry for the overhaul...apparently he never looked at the data plate either.

I also read here a coulple nights ago that the narrow deck crankshaft has "lightening holes" in the prop flange. Is this correct? If so, my crank has no holes in it (other than where the prop bolts go). Do I even have the right crank in this engine???

Also, I remember him telling me after the first engine run that it "ran good and the oil pressure came up within 6 seconds or so". I wasn't there when he ran it for the first time, but aren't you supposed to "prime" the oil system somehow prior to the first start after a rebuild???



Sorry for being long winded....
 
Interesting story. All the various pieces sound a bit disjointed to me. If it isn't the prop, strong vibrations are almost always the lack of internal balancing of the engine. Wouldn't matter which crank you have. If the crank is balanced, then it's balanced, although it can always be debated as to how well it was balanced. When I overhaul an engine, the rods also get balanced end for end, and the piston and wrist pins get balanced, so all the rotating mass is balanced and all of the mass that is moving horizontally is matched for balance. I've never had any result other than a smooth engine.

I have seen engines that were so out of balance that you could watch the nose of the plane move around following the heavy side of the crank as you shut the engine down. When I topped that particular engine, the problem was all in the weights of the rods.

As for the "FOD" and other internal damage, it sounds like everyone is trying to dodge a warranty job and you are about to get stuck for it. This reads to me like the rings weren't checked or properly fitted. The things you are listing off is the exact reason why I have built my own engines for the last 25 years now. I learned the hard way not to trust anyone with building my engines. The A&P license (and I have one) doesn't guarantee competence. One of the worse engine disasters I have had was put together by someone that had been in the business for 40+ years.

-CubBuilder
 
Not a good situation no matter what.

If you have the log books and parts list that was signed by the mechanic, and can determine that the wrong parts were installed, then you may have some hope.

Otherwise, it is going to be a big argument, and you will be having little satisfaction.

Before you even go down the path, you need to ask if the mechanic has insurance, or will even be able to pay for repairs if you prevail.

If not, you are out the $ no matter what.

About the best you can do is ensure no one else gets stuck by them...

Check parts numbers against what is legal to be installed. If you can determine a problem then talk to the mechanic. (take photocopies, not originals).

Give the mechanic the opportunity to make it right. You never know.
 
Was the damage to all four cylinders or was this just one????
A or one washer would only damage one cylinder and out it would go. Unless it sucked up a whole bag of washers....

Un balanced crank and un balanced connecting rods may make an engine that is not perfectly balanced but it should run great to TBO just not as smooth. IT also would not cause FOD damage to pistons.

Sooo ECI cylinders are hard to mess up. Practically just bolt the thing on.
Why did they send in the cylinders for warranty? It does not sound like there was anything at all wrong with them other then the junk they sucked up.
 
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..........
....All the various pieces sound a bit disjointed to me.
This is whats so confusing to me. What caused what and when. I think whatever was wrong, was wrong from the start. As far as the balancing goes, Larry never missed an opportunity to tell me how "good of an engine builder I am", and how he balances everything for this reason and that reason....thought I didn't have anything to worry about...
.
As for the "FOD" and other internal damage, it sounds like everyone is trying to dodge a warranty job and you are about to get stuck for it.
Agreed

-CubBuilder

....If you have the log books and parts list that was signed by the mechanic, and can determine that the wrong parts were installed, then you may have some hope.
I know the cylinders were correct, cam and crank were original, but sent out for the appropriate inspections, I'll have to look at part numbers

Before you even go down the path, you need to ask if the mechanic has insurance, or will even be able to pay for repairs if you prevail.
I know he has insurance, but given the information presented I'm on the defensive until I look further into it...his word against mine

Give the mechanic the opportunity to make it right. You never know.
Definately will. I got a little heated with him on the phone today I shouldn't have, but after he tried to tell me this all happened in the last 3 hours I lost it. I will apologize for my tone, and try to convince him to share some of the labor cost going forward...If he wants to make some money off me from the repairs thats fine, otherwise I'll gather my parts and pay somebody else to do the work, if for nothing else other than spite.

Was the damage to all four cylinders or was this just one????
Apparently all four damaged, but only the one has the nicks and dings from the FOD.

A or one washer would only damage one cylinder and out it would go.
This is the reason I'm so confused about what happened

Sooo ECI cylinders are hard to mess up. Practically just bolt the thing on.
Yes, he never took the pistons out of the cyls prior to install, ECI recommends this as long as they havent been sitting around for too long.

Why did they send in the cylinders for warranty?
He sent them to the vendor because he thought ECI didn't set the rings properly. He was just going through the proper channels I guess. He probably never saw the marks on the one cyl. The vendor then sent them to an outfit that apparently ECI uses for warranty inspections
 
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.... As far as the balancing goes, Larry never missed an opportunity to tell me how "good of an engine builder I am", and how he balances everything for this reason and that reason....thought I didn't have anything to worry about.........

I am sorry for your troubles, this does not sound very good.

Exactly what did Larry mean when he said that he balances "everything"? Why didn't he weigh the pistons to make sure that they were balanced. If ECI had installed a wrong piston, he would not have found it. Maybe a 160 piston in one cylinder? How did he perform the balancing? Did he grind metal from rotating parts? Does he have the fancy machinery to be able to accomplish this? True balancing is an art usually performed on high RPM engines. Our airplane engines are not high RPM. Assembling an engine in accordance with the Lycoming manual will produce an engine that runs very well without any "I can do it better" input from an average A&P.

You mentioned FOD on piston domes (plural). As Alaska Rallyer says, FOD in more than one piston? I assume that you do have an air filter? Are there any parts or pieces missing between the filter and the tops of the piston?
 
Just pulled a 0-320 b2b apart. Was really surprised the amounts of carbon thats stuck to the tops of the pistons, i could see how this could easily chunk off. My rods and pins are all within 1 gram of each other. Bought new pistons for it but i bet with different companies you could get a really big variation in weights from one to the other. I might be off on this but with the possible carbon built up and or letting go on one, difference in manufacturers pistons from one supplier to another, and differences in the same manufacturers pistons it could get up to close to 50 grams difference. Some wont put a motor together if theres over 1 gram difference with everything. If i ever have to replace a cylinder and the motor runs smooth im going to weigh the old and the new piston. If possible. Even the piston pin plugs from the first aluminum to the brass aluminum are 17 grams different. Thats alot. Lot of these little things that could add up to a wiggle. Now after typing this and reading the above i will have to weigh the old pistons and see what i had. The new ones are all exactly 1269 grams. And all the pin plugs are the same at 31 grams. They put the weight of a new piston on the box for a reason. Just trying to help to get a thinking process going here.:lol: And usually in cylinder replacement the weight of the piston is printed on the bottom of the piston in the cylinder. Another thing that could contribute is engine mount bushings and i dont know if it would ever happen but also a thick walled piston pin in with some thin ones, that would make er shake.
 
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I am totally confused now...

how did he balance if he never took the pistons out?

Is it possible that a pin cap was forgotten? A pin can cause lots of sidewall damage.

Where is the cylinder damaged?

I like Skywagons' question: what parts are missing from the bottom to the top?
 
I would never install a cylinder without pulling the piston out and checking the dimensions and rings. Found a std. piston installed in an oversized cylinder assem. yellow-tagged from an overhaul shop. Found a casting flaw in a factory 0-470 ring once, would have failed in a very short period of time...

Very sound advice above about checking for missing parts upstream from the cylinders....
 
Would that mean he did not follow the overhaul manual?

Can you converse via email and get a statement that he installed without removal of cylinder?
 
Exactly what did Larry mean when he said that he balances "everything"?
I think now, that he meant that he "weighs everthing to make sure its pretty close"

Why didn't he weigh the pistons to make sure that they were balanced. If ECI had installed a wrong piston, he would not have found it. Maybe a 160 piston in one cylinder?
He said since I bought a set of 4 that they would be close in weights from ECI. I think we can rule out wrong cylinder parts since they've all been instpected,

You mentioned FOD on piston domes (plural). As Alaska Rallyer says, FOD in more than one piston? I assume that you do have an air filter? Are there any parts or pieces missing between the filter and the tops of the piston?
This is something that I have yet to clarify. I received notice of all this yesterday (Friday) just before 5PM, couldn't call anybody down there to find out from the horses mouth. As far as parts go, what parts could possibly come loose starting from behind the air filter??? I guess something could have come through the carb heat??



I am totally confused now...

how did he balance if he never took the pistons out?
Not sure, like I said above I think he just looked at the weights written on the piston bottoms to verify they were close

Is it possible that a pin cap was forgotten? A pin can cause lots of sidewall damage.
There was some sidewall marks from the pin caps but I think it was normal, at least thats what I've been told.


Where is the cylinder damaged?
"Foreign object debris damage on piston domes. The damaged spots were up to a 1/4 inch across and .015" deep. The piston skirts also were scuffed, 1 piston had a bent oil control ring and a broken peice of ring land that fell out of the piston after removal" This is from the inspection report. I won't be able to clarify anything til Monday earliest.


I would never install a cylinder without pulling the piston out and checking the dimensions and rings. Found a std. piston installed in an oversized cylinder assem. yellow-tagged from an overhaul shop. Found a casting flaw in a factory 0-470 ring once, would have failed in a very short period of time....

Ya, I think a lesson has been learned here. Funny thing is, if Larry has been "rebuilding engines for 50 years", you would have thought he would have known to check the rings prior to assembly.

Sounds like he didn't even check the ring gap??

Nope


I'm probably gonna head down to Lompoc today or Monday to look at my engine and talk with Larry about what to do next. You can bet I will have a ton of questions for him.

As for the cylinders, it looks like they will need to get repaired, honed? bored out? I don't really know yet.
 
Would that mean he did not follow the overhaul manual?

Can you converse via email and get a statement that he installed without removal of cylinder?

This is a good idea...

On edit: I'm going over any old email exchanges during the rebuild time to see if I can find anything about this
 
Is checking the ring gap part of the procedures in the o/h manual?

If so, and he did not do it, you have some hammer to get participation from him.
 
As far as parts go, what parts could possibly come loose starting from behind the air filter??? I guess something could have come through the carb heat??
The engine in my Cub came from another (not a Cub) airplane. A screw, which held the air box to the fuel servo, had backed out and was swallowed into one cylinder producing a lot of isolated damage. One cylinder assembly was replaced.

Do you have heat studs on the exhaust pipes? If one or more of these broke off they could have been sucked in through the carb heat system. There are several places something could break off to be sucked in. You might not even be aware that a part broke.
 
In 1999 our flying club had a well respected local mechanic do our overhaul and shortly after return to service there was a problem with one cylinder. ECI provided a warranty replacement and our mechanic put the engine back together. 10 hours later the engine failed in flight and one of our guys did an excellent job landing in a plowed field - no injuries, no airframe damage, and only ruts in the field. During the engine teardown the FAA found a missing part in the warrantied cylinder (sorry guys, too long ago to remember was was left out). Turns out ECI sent the cylinder and piston with paperwork indicating it was a complete assembly. In his haste to get the engine back in service our mechanic installed the "assembly" without tearing it down and inspecting the pieces and assembly work. The mechanic's position was you sent me paperwork that you were providing a completed assembly I should have to teardown, inspect, and reassemble. ECI argued that he should have torn down and inspected prior to installation. ECI's insurance company paid us enough to buy a new engine since the core was trashed.
 
WOW!
This is a very interesting thread. I'm glad I'm not looking for any new customers. Some folks sure want to blame the mechanic. I think I'll start working on Fords.
Here is an important quote....
"he never took the pistons out of the cyls prior to installing, ECI RECOMMENDS THIS....."
When you buy a new or yellow tagged carb, do you tear it apart to make sure the float level is correct?

Can a nonmechanic remove and reinstall spark plugs? I don't have my FARS handy or I would know the answer to the question.
 
T.J,

if you were to balance an engine, would you not take the pistons out?

It is strange that all cylinders are bad. The rough running from the beginning sounds like something in the build was not right.

What is your thought? Where would you start looking at cause/responsibility? Hard to drop a plug washer into a cylinder, isn't it?

I think the plug change for owners is in the 'owner maint.' section.
 
If the pistons were not removed from the cylinders before assembly, do you think the preservative oil failed as a lubricant and the cylinders were scarred on the initial start up? jrh
 
If a hydraulic unit in a lifter isnt working right will that maybe make it run a little off and possibly lean enough to score a piston?
 
I went to the hanger and checked the FARS. Part 43. A licensed pilot can in fact clean/replace the plugs on his own plane.
If the oil analysis was ok 3 hrs before the problem, I would suspect something happened in that 3 hours. Is it possible something could have fallen into the top plug holes while the plugs were out? Plug washer won't fit the hole, has got to be something else.
George, I've never balanced an airplane engine. If I did, I'm sure I would remove the pistons.
Prime the oil lines.....Nope never on a Lycoming, yes on 4 cylinder Continental. I just leave the top plugs out, turn engine over and that will fill /prime the oil system.
Scoured cyl walls.....I would suspect either the wrong rings were installed or the proper break-in procedure was not followed. Although the scoured material should have shown up in the oil analysis.
Did you maybe overtemp the engine in the last 3 hours? Was the paint discolored on the cylinder barrels?
 
...If the oil analysis was ok 3 hrs before the problem, I would suspect something happened in that 3 hours. Is it possible something could have fallen into the top plug holes while the plugs were out?
Highly unlikely as I changed the plugs at the 10 hour oil change.

Scoured cyl walls.....I would suspect either the wrong rings were installed or the proper break-in procedure was not followed. Although the scoured material should have shown up in the oil analysis.
The second ground run (I wasn't around for the first) was a short warm up to 200 degree CHT, then a smooth transition to 2200-2300 RPMs for about 10 seconds, then a smooth transition back to idle for about 10 seconds then shutdown. Afterwards opened the cowl doors to check for leaks, then the first flight. Flight lasted 30 mins...RPM 2450, Oil temp 205, Oil Press 52, CHT just over 400 steady, this was at 0.2 SMOH. Oil pressure was adjusted by adding 2 washers, but subsequently never ran much higher than 65-70 psi.

Did you maybe overtemp the engine in the last 3 hours?
Absolutely not

A Was the paint discolored on the cylinder barrels?
No

Today I was able to get enough oil out of the oil cooler for a sample, this will reflect the last 3 hours run-time (all accessories were removed prior to bringing the engine back to him, per his request). Then I drove down to his shop and got another oil sample from the leftover oil in my engine. He had already split the case, but hadn't yet cleaned anything out. Both of these oil samples are not ideal in terms of quality, but should still tell a story regardless...he mentioned that he took an oil sample as well. Samples will be sent out monday.

We had a good talk about everything, I wasn't blaming him for anything, just trying to figure out what went wrong and discussing options from here on. He did say he wouldn't charge me his full overhaul rate, but somewhere around half price. I thought this was curious...

I doubt that we will ever find out what really went wrong here....
 
Oil sample is meaningless at this point. Sounds like the warranty period ended when you turned the key.

Not all engine shops have no warranty... I had a factory overhaul start making metal around the 200hr mark. I sent them a few oil samples and the whole filter. After only two TWO very quick phone calls to Lycoming i had a factory overhaul air freighted to me by the end of the week. They never charged me for the 200hrs i had put on the engine, i gave them a bill for the engine R&R, prop flush, oil cooler flush, prop governor flush and my labor and they sent me a check. This was a $55,000 overhauled engine no small change.
 
You weren't around for the first run? No pre-oil? Pistons left in cylinders without checking rings etc... Was there any assembly lube on anything? How long was it run before the oil pressure came up? Any parts missing, broken or bent under the rocker covers? (valve spring keeper, pushrod end....etc) Bummer of a worse case scenario O-320 O/H.... I just can't imagine starting a fresh overhaul without motoring the oil through it first with the starter and making sure that everything was well lubricated....biggest red flag for me right there...not checking cylinder assem is second. Old habit that I have is pulling the piston out and pouring stoddards solvent in the cylinder and checking for valve/seat leakage....

TJ, I don't agree with the yellow-tagged carb analogy. A carb is thoroughly bench tested for flow and leaks and then sealed/safetied and yellow tagged... A cylinder assem is a group of parts that need to have a final assembly performed. Then you sing it off as being good. I'm not comfortable assuming the parts are correct before the final assembly...
 
Oil sample is meaningless at this point. Sounds like the warranty period ended when you turned the key.

.

His contention is that all this damaged happened in the last 3 hours since the oil sample from hours 10-25 came up clean. He assured me that the oil sample results were undeniably, without a doubt, scientific proof that nothing happened prior to 25 hours in service. If the oil sample I gathered from the oil cooler and the engine (last 3 hours) comes up clean, that shoots his whole argument down and points to the first 10 hours of operation, where the last hands to touch the engine were his hands....if it comes up dirty, then I'll admit defeat and reluctantly fork over another $8000 and chalk it up to bad effing luck.

If the engine started shaking at hour 25 I might be able to swallow this pill, but in my opinion, whatever happened to this engine happened during the first engine run because the engine vibrated consistently from DAY ONE. I'm no greenhorn pilot, I fly helicopters for a living and pay VERY CLOSE ATTENTION to any unusual vibrations. Nobody took me seriously when I complained that there was something wrong with this engine...I made believers out of them.
 
TJ, I don't agree with the yellow-tagged carb analogy. A carb is thoroughly bench tested for flow and leaks and then sealed/safetied and yellow tagged... A cylinder assem is a group of parts that need to have a final assembly performed. Then you sing it off as being good. I'm not comfortable assuming the parts are correct before the final assembly...

So you get a overhauled or new cylinder remove all the valves and measure the fits and clearances? Do you remove the the guides and valve seats to?
 
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