C-170A Airforms Baffle kit on a C145-2H?

[Toddav8r]

Anyone ever install a C-170A Airforms Baffle kit on the C145-2H? This engine came out of a 170B, and we are installing it on our A model, and the A model baffles interfere with the Hydraulic Propeller control at the left front of the case. We will install our fixed pixed McCauley prop and leave the lever saftied as is. What is odd is the logbook and the dataplate both say its a C145-2, but the serial number has a D in it indicating a dampened crank and I thought only the C-145-2H (and the O-300B) had the hydraulic propeller control mechanism, so it's got to be a C145-2H, right?

Anyway, being that I hate the thought of having to cut and modify these beautiful baffle pieces in order to make them fit, I called Airforms to see if they had ever dealt with this particular issue and they have not. There recommendation was to do whatever I needed to make them fit, and I was just wondering if anyone else had ran into this issue.

[Bruce Fenstermacher]

Got to be a 2H? No, it could be a mix of parts. For example 2H case halves used to repair a -2. Your engine is what the data plate says it is. Dampened cranks are found in -2 and 2H and 300A and B.

[GAHorn]

Trim the baffle to fit…and get on down the road. IMO

[darhymes]

My engine is C-145-2H and recently installed new Airforms front baffle pieces. Fit was pretty straightforward. Just had to do a little trimming to get around the armature. As a matter of fact, both front pieces needed some trimming to get a perfect fit (there is bolt that protrudes on the right side).

On another note…after the install, I found my front cylinder temps dropped dramatically (from 350s down to 280s) and the rest of the cylinders got hotter (up to 390). Go figure. Ended up copying the portion that covers the front part of cylinders 5 & 6 from an early 172 and I added that portion the Airfomrs baffle. All the cylinder temps are pretty even now.

[brian.olson]

Dustin - would you, by chance, still have the templates that you used for the front baffles that you copied ... and would you be willing to share the templates/photo?

Brian

[GAHorn]

Good on ya’, Dustin! This is an oft over-looked feature…. it even took Cessna awhile to figure it out. (but look at the 172s from the very first ‘56 models)

It may seem counter-intuitive (at first)…but if we remember this is a “down-draft” cooling system…and that ram-air (relative wind) blasting against the front face of cyls 5/6 …will disrupt and reduce downflow to those two cyls…and subsequently they run un-even temps….. Cold at the face and hot on the back and bottom.

By adding a “front wall” to those two cyls…all the air is forced UP/OVER the top of All Cyls….and high-pressure will exist above All Cyls… which then is forced Down thru all the cyls more equally.

<edit> corrected pic captions

‘56 and later 172 models, NOTE added Items 1A and 7A added after SN 36996

‘53 and later 170-B models

[Toddav8r]

Dustin-

Like Brian, I'd like to know if you could provide any templates or pics of your front plates. Sure makes sense.

[n2582d]

A instructor at Continental said a finger-size hole in baffling equals a 20° rise CHT.

For $180 each one can buy these individual baffles from Airforms. Would still need to be modified to fit the early 170 baffling. This topic is covered here. I wonder if Airforms would omit the hole in front of the #5 cylinder as discussed in the other thread. Probably not, as it is a PMAed part.

[brian.olson]

Gary - a year and a half ago I tried to purchase just those two pieces from Airforms, but they would not sell them to me because my serial number did not match the serial number spread for the PMA for those pieces/year ... I hit a wall. I spoke with a couple people there before getting shut down. Full transparency: I had new baffles from Airforms installed on my 170A a year after I purchased it, and they are great.

[n2582d]

Brian,
Interesting, as their prototype on Richard’s 170A included these baffles. I wonder if one would find the same restriction buying them from McFarlane. Of course, if just looking for a pattern, obtaining samples from a salvage yard would be the way to go.

[Karl Towle]

I find these comments about AirForms interesting. They made, and shipped to me, a custom rear bulkhead omitting multiple holes that would normally have been drilled through it. I had changed to Slick mags, and decided to go with their bulkhead fittings for the wires to the top plugs. Really cleaned thing up IMHO. As for them not selling you a part, I should think one could find a year, make and model that would satisfy them and order for that. Something recently purchased maybe.