Building an Experimental PA11
- Thread starter Dan Gervae
- Start date
Dan Gervae
FRIEND
Upper Peninsula of Michigan
Ironically that went away after I indexed the prop 180 degrees. But I hear what your saying….it sure had been running well too. It’s not the end of the world. I’ll fix it right. It wasn’t stuck too bad and I hope I can get it feeling good again before Oshkosh/New Holstein.
BC12D-4-85
SPONSOR
Fairbanks, AK.
Hi Dan....I knew you got it figured out so my comments were just speculation. I hope it gets looked at.
Actually there is a product that has been proven to remove valve and cylinder carbon. There are other brands but this is what I use. It was originally developed by the outboard motor industry that was forced to deal with carbon buildup prior to modern synthetic oils (they called it a motor tuner). Now it's popular when dealing with intake valve sticking in gasoline direct injection (GDI) motors that don't feed fuel upstream of that valve. Carbon forms from inducted crankcase fumes and stem leakage. The active ingredient is Polyether Amine and has been sold by Chevron as Techron fuel additive.
Gary
Actually there is a product that has been proven to remove valve and cylinder carbon. There are other brands but this is what I use. It was originally developed by the outboard motor industry that was forced to deal with carbon buildup prior to modern synthetic oils (they called it a motor tuner). Now it's popular when dealing with intake valve sticking in gasoline direct injection (GDI) motors that don't feed fuel upstream of that valve. Carbon forms from inducted crankcase fumes and stem leakage. The active ingredient is Polyether Amine and has been sold by Chevron as Techron fuel additive.
Gary
cubdriver2
FRIEND
upstate NY
MMO
Glenn
Glenn
Dan Gervae
FRIEND
Upper Peninsula of Michigan
https://www.avweb.com/ownership/dealing-with-stuck-valves/
I decided to call my IA…I told him I’d feel best if I reamed the valve guide. He offered to help as he has done it before and he will supply the proper reamer. Many say MMO, and I’m sure it has had its successes…this article says not to use it. What are your thoughts on this a web article?
I decided to call my IA…I told him I’d feel best if I reamed the valve guide. He offered to help as he has done it before and he will supply the proper reamer. Many say MMO, and I’m sure it has had its successes…this article says not to use it. What are your thoughts on this a web article?
Colorado-Cub
MEMBER
Buena Vista, CO
Like others have said, it is obvious if an engine is running MMO just by taking off the rocker cover.
I run it with good results, but for different reasons. My O235 makes lead no matter how lean you constantly run it and MMO has helped the buildup on piston tops and valve stems. In my case, it works better than TCP. Others may disagree...
I run it with good results, but for different reasons. My O235 makes lead no matter how lean you constantly run it and MMO has helped the buildup on piston tops and valve stems. In my case, it works better than TCP. Others may disagree...
Colorado-Cub
MEMBER
Buena Vista, CO
Dan Gervae
FRIEND
Upper Peninsula of Michigan
I am borescoping all 4….we have an expensive flex cam at work that I can take pictures and video with if I want…nice led light on the end. I should be able to see the stems some with the valve open. I did shut it down hot when I landed the other night and it was stuck as soon as I started it. It will be interesting to see.
compressions were high 70s when I checked them in May.
compressions were high 70s when I checked them in May.
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Colorado-Cub
MEMBER
Buena Vista, CO
I am willing to be it will be just fine after you ream it out. Good luck!
cubdriver2
FRIEND
upstate NY
Mogas or 100LL?
Glenn
Glenn
cubdriver2
FRIEND
upstate NY
MMO is a solvent based oil. My 1300hr 33 hp mower stuck a valve last summer, bent the push rod. I freed it up with MMO, straighted the pushrod on my anvil and run a few ounces of MMO in the gas once in awhile an all is good
Glenn
Glenn
BC12D-4-85
SPONSOR
Fairbanks, AK.
That can be a problem especially if the exhaust valve is still open when stopped. The hot valve has to get rid of the heat and w/o a seat to contact it drains though the guide plus springs and rocker arm. Any gunk in the guide or on the valve stem and it can make glue. Cool it off some before shutdown.
Gary
windy
SPONSOR
Utah
I had 3 stuck valves, did the rope trick to unstick & also reamed the guides and buffed the valve stems as much as possible. Everyone recommended MMO, so I tried it. Made it home then up to the Idaho backcountry and two of the exhaust valves started sticking again, less than 20 hrs after the reaming exercise. Removed the cylinders & had them overhauled by a reputable engine shop. A lot of time & money spent and the overhauled jugs got me about 400 hrs before two more valves were sticking. Bit the bullet and overhauled the engine & found a spalled cam shaft. 2400SMOH when I did the OH. If I had to do it over again, I’d have done the reaming enough to make it home, then overhaul the engine or install new cylinders. The MMO and overhaul of worn out tired cylinders were both a waste of time and money. IMHO
windy
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windy
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cubdriver2
FRIEND
upstate NY
windy
SPONSOR
Utah
100LL. I’m religious about leaning at the high DAs where I live & at all lower elevations too. The spark plugs rarely had more than a tiny lead glob or two and were always light gray. It was a LyCon engine. Cylinders were new Lyc nitride ones at the previous overhaul. It took me 8 years to put the 2400 hrs on the engine.
Dan Gervae
FRIEND
Upper Peninsula of Michigan
I was unable to get the valve freed up enough to ream the guide on the plane. Also checked the pushrod….ever so slight wobble in a drill. There was a fair amount of crusty carbon build up on the springs and around the guides. I decided to buy 4 new jugs…about $1K each. I called Lycon and they said TCM Continental cylinders went up $700 on July 1st, so I decided to buy Superior Millenniums. They will be here Tuesday, so if I get it going I’ll still aim to fly into NES Holstein then Oshkosh. I have a puke of pushrods to weed through to find one serviceable/within tolerances. Since my cylinders are fairly low time I will see about cleaning them up and either build a spare motor, or keep them around as spares. Hopefully prices don’t get too out of control….but I decided to hedge my bets and buy the Millenniums while they are still “cheap” eye roll.
BC12D-4-85
SPONSOR
Fairbanks, AK.
From what I've read it helps to keep the oil from getting bulked up with combustion byproducts. That can lead to excessive deposits. How much is too much - not sure. Most oil filters won't remove the fines and of course the screen doesn't either. I'd not go more than 25 hrs between changes and maybe even less if the oil turns black quickly. Oil's cheap compared with parts replacement.
Gary
Gary
cubdriver2
FRIEND
upstate NY
I was asking because most little Continentals can't handle the lead and stick a valve. 100LL has 5 times the lead that 80 had
Glenn
Dan Gervae
FRIEND
Upper Peninsula of Michigan
Ok guys…I’m looking for advice…I’ve swapped one jug without pulling the motor, but I’m aiming to do all 4 on Wednesday and Thursday….is it worth the effort tho pull the motor and place on a stand? I fell like it could save some work not pulling it. Thoughts?
frequent_flyer
Registered User
Arizona, USA
In what way is the stand you would put it on better than the stand it is on now? I don't make a career of pulling cylinders but the ones I have changed were done with the engine on the airplane.
Doug Budd
MEMBER
Crawford Nebraska
I have had a stuck valve did the rope trick then put a variable speed drill on the end of the valve stem spayed it with sea foam spray and turned it slow to clean up the carbon. It worked. I was going to pull the cylinder but didn’t. Ran it for another 100hrs before I over hauled the engine. Don’t know if that’s an approved fix but when your stuck in a neighbors alfalfa field you do what you have to.
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cubdriver2
FRIEND
upstate NY
Drill works good, I use MMO to free it up and then valve gringing compound on the shaft to clean up the guide hole
Never used Seafoam on anything, have to try it
Glenn
Never used Seafoam on anything, have to try it
Glenn
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Colorado-Cub
MEMBER
Buena Vista, CO
Use torque plates and you will be fine.
(But, please use torque plates.)
(But, please use torque plates.)
Doug Budd
MEMBER
Crawford Nebraska
It comes in a spray can to spray in the intake of a engine to clean carbon out. Used it on a s10 pickup worked great
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Dan Gervae
FRIEND
Upper Peninsula of Michigan
I could not get that exhaust valve to go into the cylinder after I removed the keepers…. I worked it back and forth with lube but it got very tight at the end….then we checked the pushrod and it has a slight wobble. I bought this engine off of a prop strike aircraft…the A&P IA tore it down and had the internals sent in for magnaflux. He install new bearings in the lower end and made a log entry as well as stapled the yellow tags in the book. It is my belief that he did not disassemble the cylinders. I bought it cheap so I have decided to put a new top end on this…I spent all this time and money building a plane…no sense skimping here. Also, these are old serial number cylinders, so timing has to be set to 24 degrees to stop the cracking issues that plagued these units…I will now be able to reset the timing back to 28 degrees which should help give me a tiny bit more power. I’ll clean the cylinders I replace all up and put them on my shelf….I think they may even work on my C 90-12F on my floatplane?? Anyway…after Lycon said prices are going way up….$700 per jug on TCM models, I decided to go this route. I had considered souping up a bit with higher compression ratio and some porting. I’m going to go this route for now….maybe when my I start setting up my floats next spring I’ll have some work done while I’m building the rigging.
Dan Gervae
FRIEND
Upper Peninsula of Michigan
I pulled the motor, removed all four jugs…the valve that stuck was starting to burn…would not have lasted too long. I will assemble with 4 new cylinders tomorrow using the torquing process as if assembling a new engine. I’m glad I listened to my motor trying to tell me something. About 35 hrs ago the compressions were all in the mid/high 70s…this valve started leaking a while back by the looks of it.
the guide was full of crud too. The other three looked better, but one had white powdery soot…(lead) ?? Lean? Cam lobes look good.
the guide was full of crud too. The other three looked better, but one had white powdery soot…(lead) ?? Lean? Cam lobes look good.
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Dan Gervae
FRIEND
Upper Peninsula of Michigan
that was a fun day. I got all the baffles on, timed back to 28 degrees (no more old cylinder service bulletin) I’ll look it over good after a good nights sleep and away we go….back in business. I like the way Superior Millenniums Are made…and they come nicely packaged….nice job. Hope they last a long long time.
Attachments
BC12D-4-85
SPONSOR
Fairbanks, AK.
More power too. Good Job Dan. Very positive.
Gary
Gary
Dan Gervae
FRIEND
Upper Peninsula of Michigan
Waiting for rain to quit so I can test fly, but I gained almost 75rpm on static run up. More than expected.
