Exhaust Pipe clearance

[UrbanM]

Minor issue here and would just like to find out what others are using. I just overhauled my 0-320 in my 6A and during the reinstallation of the exhaust I noticed evidence of contact with the part of the engine mount that supports the nose gear strut. My AI-A&P buddy suggested Adel clamps at the effected area. This works but the padded clamps (Or at least the ones I found) are thick and make contact with the exhaust when I adjust for adequate spacing with the cowl. What I need is something thinner and not sensitive to heat so contact will be kept to a minimum. I have a buddy who uses fire sleave like what one finds on a fuel line. The would be heat tolerant and thin enough. I have also found some high temp (450F) fuel line on McMaster Carr. Is there anything else I should consider?
Thanks,
Kirk

 

[Stevea]

Kirk,
Fellow 6A driver here, although with an O-360 and the then "standard" Vetterman crossover exhaust system. I'm not sure...are you concerned about contact and abrasion between the exhaust pipes and engine mount, or radiant heat from the exhaust pipes to the engine mount.....or both? I can't picture where an adel style clamp or fire sleeve comes into play here.

My exhaust pipes manage to fit nicely in the small exit area of the engine mount tubes, firewall, and cowl. It stays generally where it is set....although I have had one occasion where a loose exhaust hangar allowed movement to one side, causing some minor rubbing on the engine mount tube. I discovered it early after it started, so no big wear issue to deal with. Re-aligned and re-tightened the exhaust hangars and everything was good to go. During preflight, I make sure to grab each exhaust exit pipe and try to pull it side to side to look for loose/broken pipe hangars. Also a quick look at the alignment to make sure nothing has moved, causing the pipes to contact something they should not contact. The attached photo shows most of the clearances.



One change to the exhaust I have made since the original installation. After the original hose couplings used in the exhaust hangars wore out (from heat related cracks.....just age), I changed to using MIL-6000 oil hose for these couplings....thicker walled hose than the original (so stiffer hangars), and seams to hold up better to the exhaust heat. Also switched from band clamps to constant tension (automotive) clamps to hold the hose to the exhaust hangar stainless tubes. These don't loose tension like the band clamps do (when the hose rubber starts extruding through the clamp screw slots). Have not had the pipes exit location shift at all since "upgrading" the pipe hangars.

 

[UrbanM]

Steve,
Standard Vetterman here as well. I adjusted the right exhaust pipe "IN" a little bit to keep it away from the cowl at the last annual. That might be what caused the contact. My cooling air outlet seems smaller than yours. I currently have the pipe in the center of the opening between the cowl and the strut.
Thanks for the tip on the tubing.
Kirk