C85 Questions

[dkenney1]

I have a couple of questions regarding the C85-12 that will be simple to most of you. I have about 130 hrs SMOH and i was wondering when to consider oil consumption a concern? TCM says max oil consumption of .4 qts per hour, and i don't want to be anywhere near that. I seem to be in the 10-12 hr per qt range which lately is slightly more consumption than previous. However, what has changed is I'm flying much more regularly, like 3 or 4 hours a week (averaging 1 hour flight per evening) as opposed to 2 or 3 hours a month, it's summer/very warm lately, and my A&P suspected one cylinder slow to break in and when he felt I was "babying the engine too much, run it hard 2400 rpm not 2100-2200 I was doing". Oil consumption a little higher, and after flying the spot on the floor from breather tube when from the size of a quarter to silver dollar. Anything to worry about?

Incidentally, after 20 hrs flying it hard he did another compression check, all cylinders in the 78 to 76 range. Much better than the one cylinder that was at 68 and showed a little oil inside, non found this time "looked clean and good, keep running it hard, she likes it".

The other change is I'm based at a different airport now, and MoGas not available. The plane seems to run slightly better on MoGas but I've been burning 100LL. So that means I think I have some plugs fouling. Anyone know the torque specification to tighten the plugs to? Also any good ways to clean plugs without the fancy stuff the A&P has? Should I rotate the plugs from top to bottom or one cylinder to the other?

Sorry for the simple questions. But have to start somewhere and I'm enjoying flying and learning to maintain the Tcraft. Thanks Darrin

[cvavon]

Re: C85 Questions

Run the C85 like you stole it i run mine 2500 most of the time form 0 time till now and almost no oil use and yes a drip out of the breather.

[astjp2]

Re: C85 Questions

Get an aerobatic breather from a C-150 to reduce the drip from the breather, plugs top to bottom, and get a tube and fabric A&P to help you. Many spam can mechanics do not understand the oddities of a Taylorcraft. Tim

[Mark Julicher]

Re: C85 Questions

Torque plugs to 25 lb ft.
It sounds like your engine is doing fine.

[astjp2]

Re: C85 Questions

I wont torque that high, I have had too many plugs strip the head. Good antiseize and just over snug. Tim

[N96337]

Re: C85 Questions

Champion says 360 inch pounds. I've done that for over 30 years and never had a problem...unless the cylinder needs work.
Invest in a bottle of their antiseeze....it's worth it.
If you've got 130 hours on a set of cylinders, they're as broke in as they're going to get. I agree with Chuck and you A&P, run it hard and don't baby it!! You might get it to clean up a little by running it hard, but you're not "breaking in" anymore.
I'd say the oil consumption isn't bad. It has to use some, or you've got problems. That's a bit more than usual from a fresh engine, but it sounds like you didn't work it hard right off the bat, and that's to be expected.
The breather mod talked about above will clean up the puddle a little, but I'd say it's going to be what it is, unless you do some disassembly and rework.
My plug cleaning tools consist of picks, some of which came from a dentist, and a light abrasive blast when done picking. 100LL will foul your plugs, but it's what it is. Keep it leaned and run hard and you'll have a bit less problems. I was always taught to rotate plugs top to bottom and next in firing order. Seems to help them last a bit.
JH

[dkenney1]

Re: C85 Questions

Thank you everyone for the information and help, it's greatly appreciated. Scouring the logs again, the engine has 84 hrs SMOH in October 2012. Reviewing oil consumption since this oil change 23 hrs ago and the one previous at 26 hrs I'm averaging a quart in about 14 hrs. When was running it less hard was around 18 hrs per quart, now that running it harder it's down to about 11-12 hrs per quart. All of this running is on MoGas. In the fall I convert over to 100LL since it doesn't fly much in the winter and I'm told 100LL won't gum up the carb and have moisture as easy as MoGas does when sitting for long periods. Oil pressure is rock solid at 32 PSI and doesn't decrease much when at idle.

Again I appreciate the opportunity to learn from those with more experience than me. We are enjoying the heck out of this little bird. Darrin

[Joe cooper]

Re: C85 Questions

Thank you everyone for the information and help, it's greatly appreciated. Scouring the logs again, the engine has 84 hrs SMOH in October 2012. Reviewing oil consumption since this oil change 23 hrs ago and the one previous at 26 hrs I'm averaging a quart in about 14 hrs. When was running it less hard was around 18 hrs per quart, now that running it harder it's down to about 11-12 hrs per quart. All of this running is on MoGas. In the fall I convert over to 100LL since it doesn't fly much in the winter and I'm told 100LL won't gum up the carb and have moisture as easy as MoGas does when sitting for long periods. Oil pressure is rock solid at 32 PSI and doesn't decrease much when at idle.

Again I appreciate the opportunity to learn from those with more experience than me. We are enjoying the heck out of this little bird. Darrin

You may recall I owned one of the other t crafts he built. I ran 100 octane in it and in the 85 hp champ I owned. Cleaned the plugs or at least took a look at them every fifty hours. Car gas WILL screw up the carb if it sits awhile. I think your fortunate to own one of the t crafts he built. He was a master. Mine was beautiful. There's an excellent t crft builder in Lancaster, ny. Al Zoltisch who would be a good guy to know. I would contact him. I was always told cont. Engines like to RUN, so I ran mine pretty hard. No problems. I was Very careful to change oil and filter every 25 hours. Cheap insurance. The one I bought from AL was just as nice. Both were top flight rebuilders!( A quart in 14 hours sounds ok to me.) I would probably still have that airplane if the hangar had not fallen on it during a snow storm.

[astjp2]

Re: C85 Questions

If you are losing more oil per given RPM, do a google search for the aerobatic breather. Its expensive if you buy it from Cessna but I know of others who have made their own and been just fine and it reduced the oil on the belly. Tim

[PA1195]

Re: C85 Questions

On my previous C-90 we installed the aerobatic-design breather extension...copper tubing soldered into the fitting. It helped some, but then we rotated the oil fitting and fire insulated hose up and back over the cylinders. That corrected the excess blow-by on an otherwise new and tight engine.

Gary