I reworked the baffle seals about 4 years ago. I remember it well; due to local politics I could not work in any hangar so it was done outdoors, and the (summer) wind picked up and became so strong I could hardly hold the drill. But I had to finish the job because the plane cannot be pushed back into a hangar minus the cowlings. I remember loudly cursing the capitalist culture where property owners have everybody over a barrel 
It took 2-3 hours to do it all, and a lot of time was spent on riveting the new seals on, with each rivet having a washer on it and some anticorrosive paste to prevent corrosion where it passed through the freshly drilled hole.
The upper seals were done with the Cowl Saver product and today they are still in great condition.
The “heavy silicone” material, as illustrated e.g. here I would not recommend. It is OK for the upper seals but IMHO nowhere near as rigid as the teflon lined stuff from McF, and it is totally unsuitable for the lower seals because it is too stiff and will transmit a lot of vibration to the cowling, possibly causing eventual damage to something.
Before this was done I was struggling to keep CHTs below 420F on a hot day but nowadays they rarely go above 380F, which is an amazing difference. I think the original Socata impregnated fabric seals were basically rubbish (but widely used in the industry).
There is a large selection of different types of baffle seals at Aircraft Spruce. I like to replace the bottom baffle seals, attaching to the bottom cowling (top baffle seals have already been replaced). This is for a TB20.
Thank you!
@Lucius I moved your posts into a previous thread on this topic.
I used the softer silicone-based material for the lower seals and a PTFE-coated stiff one for the upper seals. See further up the thread.
One article (not mine) on baffle seal rework is here but that guy used IMHO the wrong material for the lower seals – too stiff and it will transmit a lot of vibration to the cowling.
The stuff Socata used is OK for the bottom seals is of poor quality and starts to disintegrate in c. 10 years. It is unsuitable for the upper seals because it sags and the CHTs then start to really go up. It is the same story with the firewall foam – falls apart in a few years.
Thank you @Peter. Just to be sure, you used T-8071-3 Black Silicone Engine Baffle 1/8″×3″×9
http://www.aircraftspruce.com/catalog/appages/brown8071-3.php
and after 4 years, you still can recommend it. Thank you!
I recall I bought the bottom seal materials from Browns in the USA. It is still as good as new. The upper (teflon) stuff I would have to look up but I think I documented it here.
Hello,
Does anyone have a template that they can share? How does one go about cutting the half moon at the top, where the cowling has as “hump”?
Is the Teflon material the same no matter which edge is used? The description seems to imply that there is a stiffer side.
thank you
Gabriel Rincon
N190GT
I did mine “by eye”. It is not too critical because the air pressure pushes the teflon parts upwards against the cowling.
The teflon material is black on the outside and grey on the inside. You can see this in the photos. I can’t remember if they are of a different material.
I have used the McFarlane Cowl Saver baffle material, with the aircraft spruce pop rivet for this application on the 206. It worked well, if you can put a strong torch behind the back cylinders you will see any light coming through and you can identify any problem areas that may not have sealed. Baffle seals take a good guy at least a full day to do correctly. I couldn’t see a template off another aircraft being a big advantage.
