Exhaust manifold leak?
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Exhaust manifold leak?
My exhaust manifold (IO-540) was showing signs of blow-by where the manifold connects to the cylinders. I replaced the gaskets but exhaust is still leaking from the attachment area. I also have a Piper with a IO-540 and it doesn't have this issue. On the piper the manifold attachment lobs are much thicker. Does anyone have any suggestions on how to stop the exhaust blow-by? Thanks.
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I have a MX-7-180 with a Lycoming O-360-C1F and this happened to me when I flew to Idaho last summer. The maintenance shop in McCall ID "re-formed" the pipe with some kind of compression tool/clamp. The pipe had elongated slightly due to movement over time and I was getting a lot of exhaust blow-by from the forward end of the pipe. Worked great after they did the work and would have been a fairly inexpensive repair, but they also found several exhaust weld cracks and had to re-weld. Over the almost 20 years that I've owned this airplane, exhaust weld cracks have been the most frequent problem that I've experienced. There are several threads on it in this forum if you search. 6-cylinder engines run smoother than 4-cylinder engines and are usually less of a problem but it still happens.
Andy
1986 MX7-180
1986 MX7-180
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- andy
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As I recall, you're pretty limited in what you can do to level the connection of the pipes to the headers because of the slip joint brackets. Also, you have to watch out for small angular errors at the top of the muffler pipes because they make for big errors at the bottom of the tailpipes where the hangar straps connect. it's been a while since I messed with this, so maybe Jeremy or someone else can weigh in.
Andy
1986 MX7-180
1986 MX7-180
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Skyjunkie:
If asking about where the pipe attaches to the cylinder jug ex.port ? Then yes the cylinder ex.port face can be resurfaced, and it can be done without removing the cylinder from the engine . The resurfacing jig plate & cutter mandrill mount to cylinder's intake port studs and is powered by a 3/8" drill. Just did this to a Apache twin ( yes both engines all 12 ports)
If asking about where the pipe attaches to the cylinder jug ex.port ? Then yes the cylinder ex.port face can be resurfaced, and it can be done without removing the cylinder from the engine . The resurfacing jig plate & cutter mandrill mount to cylinder's intake port studs and is powered by a 3/8" drill. Just did this to a Apache twin ( yes both engines all 12 ports)
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Thanks VA Maule. Which tool do you recommend? I'm looking at the exhaust port resurfacing tool on aircraftspruce. It looks to be a hand crank type. Also did you grind the exhaust manifold at all? Thanks again.
Why would you jump out of a perfectly good airplane? You obviously haven't seen our airplanes.
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That's the one but it's not a hand crank the knob is for the preload/ advance the cutter. No grinding was needed pipe flanges were good ( Apache) , but weld can be applied( little at a time time so it doesn't get too hot and warped more ) than ground off, sanded down, filed, and straightedged. Straightedgeing needs to be done with the ex. Port nipples in the header pipe assembly to prevent binding of the slip joints. The exhaust system on our Maules needs to be loose fitting but secure in all joints ( jiggly) except the nipples that attache to the cylinder these need to be tight & torqued.
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FWIW - A few years back I had a crack in one of my manifolds and totally forgot about possibly welding it and just ordered a new one from Maule. The one they sent me had a much thicker flange than the one it replaced. Perhaps closer to what you have on your Piper and hopefully not as likely to warp.
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