The International Cessna 170 Association

I am a new 170 owner. I am very excited about the new aircraft I bought, it is a bit of a flying project. My initial concern is the cowling fitment. To my A&P and myself the engine appears to be too far forward or the cowling is a 1/2 in to short. The problem is the front of the case is slightly pressing against the cowling. The air intake is also touching the air filter slightly. This is the original C-145 engine, there are no apparent mods. I don't see anywhere the mount has been extended out. Having no prior 170 experience I am wondering if anyone might know why this is or have a reasonable solution for adding some space???

I am very new to writing in forums and brand new to the 170 association so not sure if I am even sure if I am asking this question in the correct way or in the correct place so forgive me if I have done this incorrectly.

Thank you,

Welcome to the IC170A Elliott! Also welcome to the ownership of a Cessna 170. There are many, much more knowledgeable members who will no doubt chime in on your questions. One thing you might do is post what model 170 you have. The cowling should fit around the air filter bracket. If it isn't doing so it will not allow the cowling to fit up to the boot cowl. Your mechanic should know this. Hopefully he is familiar with C-170's, etc. Don't be afraid to ask questions as they come up. Enjoy your new plane!

Thank you for the comments. It is a 1948 straight 170. the cowl seems to fit ok around the air filter. I believe we can adjust the airbox some and get the needed space. I just think it is strange the case is so tight against the front of the cowl. Maybe this is normal I really don't know.

Elliot, thanks for joining the association. Please feel free to jump in whenever Questions we like and pictures we like even more. Take a picture, size it to under 2k x 2k pixels and post. Then sit back and enjoy the responses. It’s “just that easy” to quote some famous individuals.
Good and safe flying with your new machine.

I had to modify my intake due to the air box hitting it. Didn't take much but it made a better fit.

John

On my '48, the cowling also wants to contact the engine case (just behind the top of the prop flange). If you let it, it will cut a hole in the cowling in short order. My cowling has a patch in that location....
A bead of silicone in the right place applied across the front of the crankcase is your friend.

It is very normal to find the case close or rubbing the cowling after 70 years. Show us pictures and we can say if you have typical rubbing or not.

Welcome, Elliot! And Congratulations on your new-to-you 170 and also for posting your question in EXACTLY the right place!
A bit of chafe-strip strategically-placed will likely be the answer, but posting a picture is always helpful.

I am a little overwhelmed by the response!!! I will not be able to take pictures and post them until this weekend. I am happy to hear this is somewhat normal. It appears to the mechanic and me it just needs some silicone and erosion tape as you all have suggested. There isn't any major damage to speak of but want to prevent any from occurring. The A&P brought it up after I questioned some vibration that did not feel natural to me. My good friend who is the A&P/IA and I don't have any 170 experience but have experience with 140s, 172, Stinsons, and many other aircraft. Thank you again for all of your encouragement and helpful suggestions.

Here is a picture I got of the cowing. I know it isn't touching but with air pressure and engine vibration I am worried it could start rubbing some.

elliott245 wrote:I am a little overwhelmed by the response!!! I will not be able to take pictures and post them until this weekend. I am happy to hear this is somewhat normal. It appears to the mechanic and me it just needs some silicone and erosion tape as you all have suggested. There isn't any major damage to speak of but want to prevent any from occurring. The A&P brought it up after I questioned some vibration that did not feel natural to me. My good friend who is the A&P/IA and I don't have any 170 experience but have experience with 140s, 172, Stinsons, and many other aircraft. Thank you again for all of your encouragement and helpful suggestions.

Some thoughts. With vibration, You might consider having prop balance checked. It’s is amazing how the sight correction of propellor balance will smooth out engine operation. Also, the picture you took of cowl and I assume crankshaft suggests you may want to check your motor mounts. See if they are worn, cracking around rubber, or causing sag of engine, this could result in cowl to engine clearance issues.

That close fit is typical. Judicious use of silicone and other anti chafe material can and will prevent any future wear.

For the last 6 months I've been repairing SR-20 and 22 aircraft.Cirrus uses a ton of Dow Corning® 736 Heat Resistant Sealant in their airplane engine compartments to seal and prevent chafing. We use it so much maintaining these aircraft we buy it buy it in the caulk gun tube size. Works really well and sets up much quicker than other silicone sealants I've used.