C-85-12 Question

[Falcon10]

I hope that the engine experts can help me with this.
My 1939 has a C-85-12. the starter and generator are removed and cover plates are installed. She has the short engine mount. I recently had a magneto problem, long story short- I had to almost completly remove the engine to remove and reinstall the eismans due to the obvious clearance problems created by the acessory case. What a pain !!
First question. Can I remove the acessory case ?
second question. If so will the magnito drives be the correct ones ?
third Will there be much affect in the weight and balance
Thanks
Falcon10

[3Dreaming]

Re: C-85-12 Question

I think Don's Dream Machines has an STC to convert a -12 engine to a -8 engine. I don't know what it will get you weight wise or for clearance. Tom

[dmcneil]

Re: C-85-12 Question

Hey Falcon10,

You could change the accessory case to the -8 type... but the changes required are many. Everything from the crankshaft gear and camshaft gear back must be changed, including the crank and camshaft gears. Additionally, the mags on the -8 and the -12 are different as they need to turn in opposite directions... the -8 are clockwise drive and the -12 are counter-clockwise drive.

There is a Continental Service Bulletin on converting engines. While it doesn't say that a -12 to -8 conversion is prohibited, it does say that conversion is not recommended because of the number of parts that must be changed and the consequent expense. You can find a copy of the Service Bulletin at www.PopAv.com Here's the link: http://www.popav.com/docs/Cont_M47_16.pdf
It's a 2 meg download if that makes a difference.

Dan

[dmcneil]

Re: C-85-12 Question

Forgot to add... you have to change the cases, too.

I don't know what the Don's Dream Machines STC does for the -12 to -8 conversion. You might give them a call and ask.

https://www.donsdreammachines.com

Dan

[Falcon10]

Re: C-85-12 Question

It sounds like an engine trade makes more sense. Anyone want trade a -12
for a -8 ???

[flyguy]

Re: C-85-12 Question

Been there and done that with the Eisemanns. Swung the engine. Had to ding the firewall a little behind each one as there was ZERO clearance.
What turned out to be the problem with your mag(s)?
Darryl

[tim]

Re: C-85-12 Question

wow what a deal big not to trade to buy i need a c85-12f so i can do that stc in to an o200

[Falcon10]

Re: C-85-12 Question

Darryl:
This airplane has been an expensive propisition from the get go.
I paid $17,500 her She was supposed to be airworthy and had a current annual. I went out to Oregon to test fly her and look it over. The logs were complete, and it had a current annual. It was advertized as having a 0 time factory OH C-85. Well after a look at the logs The real deal was this. The OH was done at a small engine shop in the Northwest. It was not a
0 time but a Major. The engine than sat on the shelf for 15 years!! So I took a look in the cyllinders and they looked good. I ran her for a few hrs on the ground and it burned very little oil and ran strong. I had been waiting for the weather to clear so I could test fly her. Three days later the weather clears and I get some time in the pattern. My previous airplane was a J-5 so I needed some dual in her also. I assumed that if the plane was in annual that it would be LEGAL. I found a few things that needed work before ferrying her home. I had to return home to go back to work. Long story made longer. negotiated the price down to the selling price of $17,500
I paid a friend of the owner to ferry it to my home field.
Now its Six months later-----
With the help of this forum I now know
1) the C-85 installed is not legal (no STC)
2) the hyd brakes (no STC)
3) the wings are from two different BC-12's
4) the fusalage ser # doesent match the A.C.
4) no paperwork for the two wing tanks
5)the AD for the coils for the Mags was signed off but NOT DONE.
6) No yoke bushings installed
7) no wheel bering seals
8) The rigging was all cobbed together and way off.
9) the wing inspection holes were never opend. and the drain holes were not burned through. Even though the IA had signed off several annuals !!!
I later learned that the IA that did the annual was half partners in the airplane!!!!!
I got the airplane rigged and the inspection holes opened. The fuel lines are the correct size for the C-85, I installed the yoke bushings. I have been flying her a bit getting to know her. She had been flying great. Up to the point that one of the Mags failed in the air. I landed back and tore the mags down. They were cobbed together from ???? The coils that were listed in the AD and signed off by the AI (1/2 owner). were still in the Mags!! I found the retaining nut for one of the gears was not saftied and backed off and the gear fell off.
I sent both Mags to Arnair for a rebuild. He was great and was able to get the mags back into shape. He told me that he dosent know if he will be able to rebuild Eismans any more due to the scarcity of parts.
I plan on buying the Harer STC for the c-85 install. I really dont want to go back to 65 hp. But for now I am going to wait to see what the outcome of the strut inspection looks like!!!

[flyguy]

Re: C-85-12 Question

Boy, does that sound like an airplane I know well, LOL.
Don't get too carried away on taking a lot of action on straightening out the paperwork. If it grounds the airplane, do it, if not, well, just think about it a lot.
On the 85. If you don't have all the records from the FAA, get the $10 CD from them. The 85 may have been done on a 337, that is the way mine was done and the FAA confirmed that it was/is perfectly legal.
My plane is actually at BC12D (dash not valid) with an eighty five and is only good for 1200 lbs. So it really isn't anything, although it is registered as a BC12D-85.
If any questions I can answer as to how mine is or whatever, let me know.
DC

[matsuthunder200]

Re: C-85-12 Question

It might be alot cheaper to just go with a long mount. if you can find some cowlings somewhere.

[astjp2]

Re: C-85-12 Question

Well about half of the problems that list are not that big of a deal, if you have logs and someone changed the fuselage, just get it noted. Different wings? So what, I built one of mine from a pile of parts because it was easier to start over than try and fix what I had, brake seals? no big deal, If you look on the 337 page, you can see that you can get the short mount approved with the 85, you could even install a small starter and an oddessy battery to keep the electric start. I did a full rebuild on a prewar and got a little stupid about trying to keep things original. I wound up making a but load of parts like new cable guides and yoke blocks from 1/4" phenolic. I dont think that most inspectors could tell the difference. Just take one thing at a time and you will get it up to the standard that you want.
Did you find any automotive parts for the fuel system? They are totally legal!
Good luck Tim

[crispy critter]

Re: C-85-12 Question

Darryl:
This airplane has been an expensive propisition from the get go.
I paid $17,500 her She was supposed to be airworthy and had a current annual. I went out to Oregon to test fly her and look it over. The logs were complete, and it had a current annual. It was advertized as having a 0 time factory OH C-85. Well after a look at the logs The real deal was this. The OH was done at a small engine shop in the Northwest. It was not a
0 time but a Major. The engine than sat on the shelf for 15 years!! So I took a look in the cyllinders and they looked good. I ran her for a few hrs on the ground and it burned very little oil and ran strong. I had been waiting for the weather to clear so I could test fly her. Three days later the weather clears and I get some time in the pattern. My previous airplane was a J-5 so I needed some dual in her also. I assumed that if the plane was in annual that it would be LEGAL. I found a few things that needed work before ferrying her home. I had to return home to go back to work. Long story made longer. negotiated the price down to the selling price of $17,500
I paid a friend of the owner to ferry it to my home field.
Now its Six months later-----
With the help of this forum I now know
1) the C-85 installed is not legal (no STC)
2) the hyd brakes (no STC)
3) the wings are from two different BC-12's
4) the fusalage ser # doesent match the A.C.
4) no paperwork for the two wing tanks
5)the AD for the coils for the Mags was signed off but NOT DONE.
6) No yoke bushings installed
7) no wheel bering seals
8) The rigging was all cobbed together and way off.
9) the wing inspection holes were never opend. and the drain holes were not burned through. Even though the IA had signed off several annuals !!!
I later learned that the IA that did the annual was half partners in the airplane!!!!!
I got the airplane rigged and the inspection holes opened. The fuel lines are the correct size for the C-85, I installed the yoke bushings. I have been flying her a bit getting to know her. She had been flying great. Up to the point that one of the Mags failed in the air. I landed back and tore the mags down. They were cobbed together from ???? The coils that were listed in the AD and signed off by the AI (1/2 owner). were still in the Mags!! I found the retaining nut for one of the gears was not saftied and backed off and the gear fell off.
I sent both Mags to Arnair for a rebuild. He was great and was able to get the mags back into shape. He told me that he dosent know if he will be able to rebuild Eismans any more due to the scarcity of parts.
I plan on buying the Harer STC for the c-85 install. I really dont want to go back to 65 hp. But for now I am going to wait to see what the outcome of the strut inspection looks like!!!

A couple of things that might help you out....Some of the taylorcrafts came from the factory with 1 and/or 2 wing tanks installed and no specs sheet or paper work to show it was done(Crispy Critter was one of them).Some also came out of the factory with paperwork that did not match the s/n stamped on the fuslage(again Crispy was one). The mags should time for either right or left rotation...if you buy new slicks they have enough room to remove and reinstall without pulling the engine loose. It's not all that uncommen to see mis-matched wings but you want to be sure to see that are both 15 rib wings(or at least they have the same amount in each wings.
Best of luck.

[wlas]

Re: C-85-12 Question

The easy fix is slick mags, they go in and out easy. I have a 0-200 on a short mount and there lots of room. I've build up a few -8 from -12 and that's ok , changing mags is a pretty quick fix.

[Falcon10]

Re: C-85-12 Question

Group: Thanks for all the help. I will keep an eye out for some Slicks.
The wings are both 15 rib and are in good shape.
I have been looking through the logs and there is a 337 for the Installation of a C-75-12
I wonder if I could just move the green arc on the tach to limit it to the rpm to 2275 rather than the 2575. There is also a letter from continental
that approves a reduction from a C-85 to a C-75 !!! However the serial # on the engine is not the one installed.
The airplane flys great, I am only conserned about being able to geting the annual done when it comes around.