It was almost a month ago that we decided to replace all four cylinders on the Valkyrie?s 1500-hour engine due to excessive oil consumption and low compression. It really didn?t take very long to get the new jugs in hand (a couple of days from A.E.R.O.), the old jugs removed, the engine compartment cleaned up, and the engine re-assembled. All-in-all, about a week for the mechanic work while doing my normal job. Unfortunately, I also had a week-long business trip and another week spent at Sun ?n Fun thrown in there, so it wasn?t until last week that we were really able to fly the airplane and break in the new Nitrided Lycoming cylinders.
The break-in philosophy was as documented by Lycoming, ECI, and Mattituck (all three have handy reference guides). 65-75% power to provide adequate but not excessive BMEP to seat the rings, shallow climbs to keep lots of cooling air going through the cowl, careful monitoring of CHT?s to make sure that things didn?t get out of hand, and richer-than normal mixtures to help with temperatures (and probably to buy another yacht for the CEO of Exxon?). As expected, the first few hours exhibited CHT?s in the low 400?s, peaking about 430, and oil temps (reflecting the heat that had to be removed ) up around 220. I tried to keep the flights confined to the early morning hours to provide for lower ambient temps, since summer seems to have arrived on the Texas Gulf Coast.
It was about hour number seven, cruising over to Louisiana for lunch at 3,500?, when I noticed a fairly rapid drop n CHT?s and a corresponding fall in Oil temps. The CHT?s went down from 425 to about 370 in a ten minute span, with nothing else being touched, and the oil dropped down to about 195. There was much rejoicing ? the break-in seemed to have occurred! We enjoyed a nice lunch and departed for Houston about 1330 local, but alas, the airplane had been sitting in the sun, little cooling had occurred, and we had to climb for altitude in the heat of the day ? CHT?s were back in the 400?s again. Oh well?patience is a virtue, we were still in the early hours of these cylinder?s lives. The next flight was later that evening, and once again I saw the break-in signature after leveling off at cruise- ten minutes of higher than normal temps, followed by a drop all around.
The next morning I launched again, and this time, there were no high temps at all ? everything appeared to be much closer to ?normal? for this airplane, and I took that as a sign that the Val waned to shake things out a bit, so we commenced to yankin? and bankin?. I had avoided aerobatics completely because the slower speed associated with a couple of G?s is not conducive to good cooling. Sure enough, through ten minutes of lops and rolls, the temps all behaved normally ? slightly elevated, but within the ?good? band.
When I landed, I noted the time on the EFIS showed just shy of ten hours since the jugs were installed ? about normal for a good break-in period. It?s too early to get an oil usage trend of course, and we?ll keep the break-in oil in the sump until it?s time for a change, but overall, it looks like the transplant has been a success and I expect the Val to go a long way on these new jugs. A great side-benefit, of course, was the thorough going-over of the entire FWF installation, with lots of little tweaks, fixes, and clean-ups ? well worth the time after six and a half years of constant flight.
Paul
The break-in philosophy was as documented by Lycoming, ECI, and Mattituck (all three have handy reference guides). 65-75% power to provide adequate but not excessive BMEP to seat the rings, shallow climbs to keep lots of cooling air going through the cowl, careful monitoring of CHT?s to make sure that things didn?t get out of hand, and richer-than normal mixtures to help with temperatures (and probably to buy another yacht for the CEO of Exxon?). As expected, the first few hours exhibited CHT?s in the low 400?s, peaking about 430, and oil temps (reflecting the heat that had to be removed ) up around 220. I tried to keep the flights confined to the early morning hours to provide for lower ambient temps, since summer seems to have arrived on the Texas Gulf Coast.
It was about hour number seven, cruising over to Louisiana for lunch at 3,500?, when I noticed a fairly rapid drop n CHT?s and a corresponding fall in Oil temps. The CHT?s went down from 425 to about 370 in a ten minute span, with nothing else being touched, and the oil dropped down to about 195. There was much rejoicing ? the break-in seemed to have occurred! We enjoyed a nice lunch and departed for Houston about 1330 local, but alas, the airplane had been sitting in the sun, little cooling had occurred, and we had to climb for altitude in the heat of the day ? CHT?s were back in the 400?s again. Oh well?patience is a virtue, we were still in the early hours of these cylinder?s lives. The next flight was later that evening, and once again I saw the break-in signature after leveling off at cruise- ten minutes of higher than normal temps, followed by a drop all around.
The next morning I launched again, and this time, there were no high temps at all ? everything appeared to be much closer to ?normal? for this airplane, and I took that as a sign that the Val waned to shake things out a bit, so we commenced to yankin? and bankin?. I had avoided aerobatics completely because the slower speed associated with a couple of G?s is not conducive to good cooling. Sure enough, through ten minutes of lops and rolls, the temps all behaved normally ? slightly elevated, but within the ?good? band.
When I landed, I noted the time on the EFIS showed just shy of ten hours since the jugs were installed ? about normal for a good break-in period. It?s too early to get an oil usage trend of course, and we?ll keep the break-in oil in the sump until it?s time for a change, but overall, it looks like the transplant has been a success and I expect the Val to go a long way on these new jugs. A great side-benefit, of course, was the thorough going-over of the entire FWF installation, with lots of little tweaks, fixes, and clean-ups ? well worth the time after six and a half years of constant flight.
Paul