Engine break-in issues/advise

[newcubbuilder]

1

 

[Steve Pierce]

If you have an engine monitor dump the data. Fix it and fly it. Rings were probably seated in the 3 hours on the test stand. I would verify oil consumption and fly.

 

[Ken Robbins]

Just went through something similar in a Cessna, we took over a job for a frustrated owner. Almost exactly the same scenario and we found the CHT indications were driven high by the exhaust gas blowing on the CHT probes. We went through the engine install as if we were just doing it for the first time and found even more serious issues to resolve. I second a data review if available but likely would not fly again until the install was cross checked by someone a little more attentive. Those were pretty big oops items but I wouldn't declare it dead yet. Might consider doing an oil analysis now and watching for a hopefully improving trend over a series of short interval oil changes. We did 5 hr oil changes on the Cessna and saw the metals reduce with each change, just pulling a sample is not quite the same.
There won't be a way to restore your feelings on the engine, don't know what you can do about that.
Ken

 

[hotrod180]

.....Upon landing, we found oil all over the belly and all four exhaust pipes hanging off the engine. He forgot to tighten the bolts beyond finger tight. The bolts vibrated off immediately, and exhaust gas was pouring into the engine/cockpit, melting the chafe tape on the cowl, and the spark plug line holders. The oil line to the oil cooler was not screwed into the back of the engine all the way and lost about a quart of oil in the about10 minutes we were in the air......

After a 3 hour run-in on a test stand, I wouldn't worry about the rings. But I would give some thought to what damage your potential over-temp did.
My bigger worry would be-- what other mistakes were made?
A loose nut or unsafetied bolt in the flight controls or structural connections could make for a bad day
if it was to rattle out at an inoportune moment.

 

[mvivion]

Yes, go over EVERYTHING you can get at. There are things that could be a lot more catastrophic than loose head pipes in that flight control circuit, engine mounts, etc, etc. if it were me, I’d try to get a third set of eyes to go over everything that’s accessible.

MTV

 

[DENNY]

Most of the guys I know will try to have one or two final inspections by someone else not involved it the build look things over. It is very common to find stuff that was missed even by guys/gals with the best of reputations. I would not worry about the oil temp, if you are just change it. Why was he leaning an engine while trying to break in it at 10 degrees?? Some have the impression that the cylinders have to get hot for the rings to seat,(over 450 degrees) this is not true. I suspect you have electronic mags, set the timing to stock for break in you can advance it latter if your CHT's get under control. Dump the info from the engine monitor and look at your fuel flow, make sure you are getting enough fuel to the engine (look at the chart for RPM/FUEL use sage). It has already run 3 hours so before the next flight after everything is fixed do a 10 min run up and them take a real good look with mirror and light to make sure everything is good to go. Then stay 1000 feet above the pattern for the next hour, land and repeat a good engine inspection. Yours is not the first to have issues on the first run and certainly won't be the last. Keep us up to date on how it is going because.
DENNY

 

[TomT]

Is it April 1st?

 

[Mauleguy]

Unless he is the only one around I would fire him and find someone else. That is unacceptable in my opinion. I never put a nut on loose on or not safety it without marking it for later. You can not be half ass about things that are important. Could possibly kill you! Sorry I think he is covering his ass by saying it is no big deal. Maybe it is not but like you pointed out now you are the one that has the lack of confidence. If you are paying him it is his responsibility to make sure it is right. If he was a friend doing you a favor that is another story.

I have a person I know that paid to get tail wheel instruction and he wrecked the airplane with the CFI in the airplane. The CFI washed his hands of the issue saying he could not do anything. What is the point of paying for a CFI or mechanic if they are not ultimately responsible if something goes wrong. I know when I got my tailwheel sign off the guy who did my training saved me from myself several times before he signed my log book. He was the one responsible for keeping the airplane in one piece not me... I get irritated when I hear people get paid and don't do their jobs. Maybe it is just the old guy in me coming out but if I screw up it's me who pays the price to make more machined parts in my shop. I will have to buy more materials etc., you make the job correct at your own expense.

 

[Formandfunction]

Completing a task to it's finish before moving on is the only way to work on a airplane. If I install something it gets the torque,safety wire or cotter key before I walk away.
Torque on the exhaust is a pretty basic step that tells alot about the rest of the install. With that kind of money invested and more importantly your life involved I would probably locate someone more competent than the current mechanic.
Not to say that mistakes don't happen but that's a pretty big one that the a&p had an opportunity to catch on several occasions from final inspection to initial run-up.

 

[supercub83a]

I cant imagine the CHTs got that hot, it mustve been the gas hitting the probes. Maybe someone with more experienced can chime in, but I would think you would see paint peeling and bubbling on the cylinders if they actually got that hot? I dont think I would let it bother me, check everything well, third set of eyes on it all and then fly it. If the data shows over 500 degrees maybe a look at how quickly it cooled at shutdown could be used to discern if the cylinder was actually that hot or if it was just the probes and wires being hit with 1300F exhaust.

On another point made by maulguy, I never tighten anything finger tight unless Im torquing it all the way. Ive caught too many loose nuts that I finger tightened and because they looked tight I missed it. Ive become a fan of torque seal too. Quick visual to let me know it was checked with a wrench.


Sent from my iPhone using SuperCub.Org

 

[BC12D-4-85]

"...I'm not a mechanic, but was involved through every step of the build to learn and participate in the build process. I don't know much about engines, so my mechanic did the engine install."

There's no simple excuse for not jointly pre-flighting the entire aircraft for airworthiness with the pilot in command. Please read this:

https://www.faa.gov/newsroom/safety-briefing/understanding-ownermechanic-roles-and-responsibilities#:~:text=Although%20pilots%20and%20aircraft%20owners,is%20ultimately%20responsible%20for%20airworthiness

Gary

 

[BC12D-4-85]

Here's the FAA's take on more than one onboard during Experimental Phase I testing. I admit ignorance but was interested, in this case, about who was or is what when it came to build, certifying airworthiness, and conducting the tests. Still am I guess.

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_90-116.pdf

Gary

 

[newcubbuilder]

Steve, Ken, Denny, Gary, everyone else, thanks a ton for your reply. I'm having a separate mechanic that's never seen the plane go over all of it tomorrow. All the wires and lines that got hot were replaced today, and I'll download the engine data and make sure nothing got over 245 and 500.

 

[dgapilot]

Steve, Ken, Denny, Gary, everyone else, thanks a ton for your reply. I'm having a separate mechanic that's never seen the plane go over all of it tomorrow. All the wires and lines that got hot were replaced today, and I'll download the engine data and make sure nothing got over 245 and 500. I already emailed JB yesterday as well. He's who I bought the engine from. Still waiting to hear back.

My mechanic said he'd warranty the engine for the first 1000 hours, for what it's worth. He's definitely missed a few more things along the way. I caught what I could see/knew what to look for, but this was a serious wake up call for him, and me. It's frustrating the FAA inspector charged $1100 to inspect and certify the plane, and missed these things (among other items we also just caught) as well. And frustrating that I never rushed my mechanic and never limited him financially. The most important thing to me from the beginning was having the best components and parts, and having it done right.

The DAR isn't supposed to do a detailed inspection. The details are part of the inspection the builder performed prior to the DAR arriving. Order 8130.2 provides the items the DAR is supposed to inspect for. It is primarily a records inspection, marking inspection (N# and placards), basic operation of controls and looking for obvious deficiencies. Checking torque is definitely not part of a DAR inspection.

 

[BC12D-4-85]

newcubbuilder, I applaud your honesty and effort to share both your experience and initial problems. If I or others seem hard edged it's because we've lost friends and family in potentially avoidable accidents. We don't want you or your A&P to be on that sad list going forward. Best wishes for your project.

Gary

 

[Cub Builder]

I've seen much worse abuse of an engine (CHT>550° and oil temp >250° with no cylinder related problems down the line. Good for having someone else go over the plane. Chalk that one up to experience. Clean it all up and repair. Have a second mechanic go over the plane to make sure all is correct. The numbers you quoted are all still in the green, so it's really unlikely to have caused any long term issues. Enjoy the next couple of thousand of hours. Try to remember they are only new on the first day. After that, it's a used plane and stuff is gonna happen.

-Cub Builder