… and what is the recommended personal intake a day?
It depends Dan. It was a liter on that particular day
I assume that ratio 1:300 is Gal MMO:Gal fuel? Da, Nyet?
Да Джеф
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… and what is the recommended personal intake a day?
I assume that ratio 1:300 is Gal MMO:Gal fuel? Da, Nyet?
Vlad, sorry, thread drift.
How do you protect the LE on your hor stab on those gravel runways?
Thanks
What are the specific symptoms of s sticky valve on start up other than the general description of "morning sickness"? Does anything show up on the EGT's? Do they stick open or closed or either? Would pulling the prop through prior to start up show a stuck valve being open resulting in no compression?
I've been following this thread as I was going to cover my tunnel since I have the Vetterman's 4 into 2 muffler and fairly easy to do. It "seems" from limited data cylinder #2 at least for the 390 appears to have the sticky valve issue and it is the hottest cylinder on 90% of the 390's being run in the fleet. From this data it seems that heat might be an issue and if that is true decreasing the airflow around the cylinders might be something that should not be done. I would hate to gain 2 - 3 knots and go through a stuck valve in the future. When it comes to engine design and understanding I really do not know enough to even phrase this question correctly buy would love for someone to weigh in on this.
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It would be interesting to know if most of the stuck valves to date have occurred in -14's with or without the tunnel flap. What I mentioned earlier is I don't understand why #2 is the issue as most data I have seen is yes #2 is warmer but still much cooler than most other Lycoming engines that I have flown. 390's seem to run warm oil and cooler CHT's.
Would pulling the prop through prior to start up show a stuck valve being open resulting in no compression?
It smooths out on the mag if I aggressively lean during runup.
My conclusion is that it is an ignition problem not a stuck valve. Wishful thinking?
Ted
RV4
Thanks for the reply. Since the engine is running smoothly on the electronic ignition, and it appears to be just one cylinder that is affected, I am concentrating on the magneto and the spark plugs. I am thinking a fouled plug on #3 cylinder. I'm still not sure if a fouled bottom plug would cause the low EGT reading, however. Will find out when I replace the plugs.
Ted
RV4
On our airport E16 (San Martin) in Kalifornia we only have UL94. The engine in my Cub runs so much better without the lead. Plugs look great at annual. Lead deposits on piston tops is dissipating. Compression is more even.
Has any one tried unleaded in their 390’s to try to eliminate valve sticking?
I’m building mine so that it’s 100% unleaded MOGAS compatible….both with and without ethanol. I want to avoid the lead deposits from the beginning. I have my -8 setup like this and she’s never missed a beat.
1. Reamer is not a good tool for the job as the guides wear oblong in opposing directions at each end. A reamer will not get all of the deposits out if there is considerable guide wear. Ball hone works better, cheaper, easier to use
I've reamed quite a bit of valve guides over the years... and not sure I'd use a hone.
A reamer will not get all of the deposits out if there is considerable guide wear.
I'm making some (slow) progress on cleaning the valve guides, but am wondering about cleaning the valve stems. They have very hard deposits on them that I'd like to remove completely before reinstalling them. What's the best way to clean the stems? I'm using a no-scratch pad, but is there a safe solvent I can use? I've read Marvel Mystery Oil will help dissolve these deposits. What else will work while I have access to the valve stems? - Thanks
However, not all stuck valves will present with morning sickness.
Another update with a problematic IO390 (Thunderbolt). Brief recap, I experienced my first sticking valve around 250 hours, combination of inflight symptoms and morning sickness. Reamed the culprit (cyl #2). Second incidence was around 380 hours (delta 130 - bad trend), again on cyl #2. I reamed all exhaust guides including performing wobble measurements. Found coking on 2 cylinders, but only #2 was below wobble specs (before reaming - within spec after). As preventative treatment (gotta try something), I added Camguard to my oil, installed the tunnel cooling flap to increase operating temps, and began cruising at higher power settings.
This month was my annual, about 50 hours since last valve treatment. I decided to proactively ream the guide on cyl #2 even though I had no symptoms, hoping that I might get to an annual preventative treatment rather than reacting to a sticking valve. I was disappointed to find the same amount of coking on cyl#2 valve guide after only 50 hours - well, not quite the same amount since symptoms hadn’t started yet.
My next reaming will occur at the earliest of 1) next annual at 120-150 more hours or 2) reoccurrence of sticking valve symptoms. Total time on the engine is now about 450 hours.
As preventative treatment (gotta try something), I added Camguard to my oil, installed the tunnel cooling flap to increase operating temps, and began cruising at higher power settings.
This month was my annual, about 50 hours since last valve treatment. I decided to proactively ream the guide on cyl #2 even though I had no symptoms, hoping that I might get to an annual preventative treatment rather than reacting to a sticking valve. I was disappointed to find the same amount of coking on cyl#2 valve guide after only 50 hours - well, not quite the same amount since symptoms hadn’t started yet.
Just as a point of reference, I've always had very cool CHT's (320-340 avg, 375 is rare on a hot day hard climb) and generally operate 50 ROP EGT (1375 ish), never had a stuck valve. Maybe just lucky?
I’ve read from our forum engine expert that we need higher temperatures to combat “sticky” valves but if that is accurate why does it seem that in the majority of cases it’s cylinder 2 that develops this issue and that cylinder has the highest temps ? Shouldn’t our cylinders with the coldest CHT’s develop sticky valves first ?
Just curious has anyone talked with Lycoming and have they offered any thoughts?
My first 14A has about 300 hours now and my current 14A just pass 120 without any such symptoms.
See post #59
Shouldn’t our cylinders with the coldest CHT’s develop sticky valves first ?