Engine Upgrade Cost

[labe0202]

Re: Engine Upgrade Cost

P10-7150, they're all the same airbox mounting pattern I believe for the small Continentals. You will not be disappointed.

Gary

Thanks, all ordered up.

[PA1195]

Re: Engine Upgrade Cost

Actually the prewar Taylorcraft uses a much different box. Tim

Thanks Tim for that correction and good to note the differences. Mine has the M/S carb and I doubt after 3000 hours the original 1941 box would still be holding hands. You can only have Atlee Dodge rebuild those old devices so many times before it's cheaper to just buy a new C-150 style part with decent shaft bearings and tighter internal clearances.

With all the hoopla Brackett brought to the air filter market about quality of air filtering it's surprising to have a look at the typically well used airboxes they're installed on. Dirt either crawls up the vent tube or orifice, or blows into the box through unfiltered tubing. Put on a relatively restrictive air filter and all you do is encourage the engine to induct more unfiltered and heated air around the carb heat flap.

Gary

[PA1195]

Re: Engine Upgrade Cost

Thanks, all ordered up.

I looked at mine today. Very nice, well made, and lots of pleated filter area compared to a Brackett with a flat foam insert. They use four 1/4 turn twist locking studs with a small cross bar that engages the back of the filter housing. Sometimes that rear housing has had the extrusions that grab the filter's cross bar flattened or worn off. If so just remove the Donaldson hardware and use ordinary bolts and locking nuts. It can help to put a smear of silicone grease (Dow DC-4 dielectric compound used in aircraft applications on oil filter base seals) between the filter and carb heat box. It can seal irregularities and prevent the rubber base gasket from sticking to the box.

Gary

[astjp2]

Re: Engine Upgrade Cost

Those are called Air-Loc fasteners. I prefer them to the screw method but many people put bracket filters on removed their nutplates and I have not found a good source for replacements. Tim

[Bravo 6]

Re: Engine Upgrade Cost

Those are called Air-Loc fasteners. I prefer them to the screw method but many people put bracket filters on removed their nutplates and I have not found a good source for replacements. Tim

Tim and Gary,

I have been following this discussion with great interest. I am in the middle of upgrading to the C85-12 myself. Utilizing the CAP stc from Terry B. and an engine from Don's Dream Machines. I just got the engine back a few weeks ago but have been on the road for work. I will try to post status and updates as I progress in case they might assist others in their process?

Regarding the air-loc fasteners, I am one of those individuals that removed the original 'receptacles' since I was utilizing the bracket filter/mount. I decided to switch to the Donaldson filter for the reasons already mentioned. I found the receptacles at the following web site:http://www.quickreleasefasteners.com/A-Spec.htm I just ordered replacements. I will try to remember to update if they work ok when I install them.

Thanks again for all the great information.

[flyguy]

Re: Engine Upgrade Cost

The first BC12 I had was a totally stripped 46 with the truss wings. Very light. It was a deadly clunker when I got it, but I discovered it had a -85 venturi and jet in the carb. It wasn't particularly fast but it would roar right on pass 65 redline in level flight and climb like crazy. Took it to 15,500 one time and it was still going up pretty good. I was just a 150 trained novice at the time and had not got into props and such so I don't remember the pitch.

So what does that make that one with the carb modification and (maybe) a flat prop. It was 74 inches I remember.

DC

[PA1195]

Re: Engine Upgrade Cost

This airbox fastener discussion is good. Not being an A&P I've wondered what the components were called and how to get them replaced or repaired. Most apparently give up and install bolts and nuts to hold the air filter. But being able to twist them CCW some to remove the filter is a benefit, especially when the backing area and nuts are inaccessible without removing the cowling.

I've had Brackett foam filter elements ice up either when flying or when operating on floats in near freezing weather (not advised and tends to lock up cables and water rudders). Being able to remove the saturated and partially blocked foam element from the front with their removable cover design is a plus.

I've not had the freezing problem with Donaldson-type filters. The wetted Brackett element is more prone to collecting water and ice on the face and has less filtering surface area than the pleated filters.

Gary

[labe0202]

Re: Engine Upgrade Cost

An update on my plane: It's in for the annual right now. A sticky intake valve was identified on the number 1 cylinder and is getting fixed right now. I just painted my Micro Aerodynamics VG's and they should be installed by week end. Got the Donaldson air filter too. I cannot, for the life of me, find a used/overhauled 1A90 prop. I thought I had a winner with a 1B90 at a prop shop in WA but it ended up being 70". Someone responded to a Wanted ad I had on Barnstormers with a 1A90/CF7444. Turns out it had been cut down to 72". Anyone out there have any insight into where something may be found?

[astjp2]

Re: Engine Upgrade Cost

I have a Sensenich M74CK746 repitched to 43 with 1036 hours total time since new. PM me if interestedTim

[labe0202]

Re: Engine Upgrade Cost

I have a Sensenich M74CK746 repitched to 43 with 1036 hours total time since new. PM me if interestedTim

What's the difference between a M74CK746 and a M74CK046? Forgive my ignorance on this but I thought there was only a 74CK-0 or a 74CK-2.

[astjp2]

Re: Engine Upgrade Cost

sorry typo....stupid fingers. Its a m74ck-0-46 repitched to 43

[cvavon]

Re: Engine Upgrade Cost

When i put the C85-12 on my plane i had a 1b90 cm 74/43 McCauley on it had it repitched to 41 got a Sensenich 76-4 I cant remember the letters 40 pitch it is 72 inch long it pulls a lot better then the mccauley.

[senior]

Re: Engine Upgrade Cost

The first BC12 I had was a totally stripped 46 with the truss wings. Very light. It was a deadly clunker when I got it, but I discovered it had a -85 venturi and jet in the carb. It wasn't particularly fast but it would roar right on pass 65 redline in level flight and climb like crazy. Took it to 15,500 one time and it was still going up pretty good. I was just a 150 trained novice at the time and had not got into props and such so I don't remember the pitch.

So what does that make that one with the carb modification and (maybe) a flat prop. It was 74 inches I remember. DC

I'll 2nd that. My T originally had a very low hr TT 65hp which pulled 2250-2300rpm on climb out.
When rejeted & larger ventura installed it turned 2400rpm on climb out.
Now with a H-Comp 85 it turns 2700 on climb out.
Each step it also climbed steeper.
All with the same 72-42 prop.
So while the 75? may not be a big power boost,
IMHO it's a very good cost effect boost if you can do it!

[astjp2]

Re: Engine Upgrade Cost

McCauley and Sensenich measure their pitches different, that maybe why you notice a performance difference.