Exhaust crack

Yesterday, after a routine oil change in my RV-14A, I performed a visual inspection of the firewall forward area. I noticed a light colored powder near the exhaust flange of the #1 cylinder. Upon closer inspection, I found what appeared to be a crack in the weld between the flange and the exhaust pipe. I used a vacuum cleaner to pressurize the exhaust and squirted some soapy water on the area. Sure enough, it leaked.

I removed the exhaust pipe on the #1 cylinder and took it to my mechanic. He thinks he can re-weld the crack which appears to be about 2/3 of the circumference of the pipe.

I’m mainly writing to raise awareness of this issue in case anyone else has a similar yet undiscovered problem. If it wasn’t for the powder around the leak I don’t think I would have noticed it. I’m very thankful I found it before the flange became completely disconnected. This also proves the importance of thorough visual inspection whenever the cowl is removed.

BTW, this header is only about 2 feet long and terminates in a slip joint. It was a tight fit getting the header off of the studs but I hit the slip joint with some mouse milk and I freed right up. I always apply mouse milk to the slip and ball joints whenever I have the cowl off and was pleased to see that it appears to be working well with 190 hours on the engine.

Thanks for the heads up. What engine/exhaust combination?

Not saying this is the case however I’m surprised the number of times I find the bolts, where 2 pipes are at a slip joint, are done up tight. They are supposed to be very loose to allow thermal expansion & just keep the pipes together.
First time I saw this was on an Rv7 with only 70 hrs - the pipe was cracked & only had 3/4” to go before it came apart at #1 cyl. The crack was very hard to see initially.
Please check those bolts.

Jetmart said:

Thanks for the heads up. What engine/exhaust combination?

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Sorry! IO-390 (original 210 hp) with Van’s stock 4 into 1 exhaust.

Great weld penetration into the pipe itself ... not so much into the flange. Looks nice tho

Vetterman exhaust repair

FYI, Vetterman cross over exhaust on parallel valve 360, RV-7A. Similar, not exactly the same.
The first time my exhaust header failed I had it rewelded and I thought it looked great. Hundreds of hours later I found it cracked again and sent it to Craig at Vetterman’s for repair. It was quickly returned with reinforcing patches added as part of the repair.

Regards,

Update…

Just a quick follow up… I got the riser back from my mechanic in three days and reinstalled it without issue. The re-weld looks great. Time will tell if it holds up. I’ve flown about six hours since the repair… so far so good.

Roy Thoma said:

FYI, Vetterman cross over exhaust on parallel valve 360, RV-7A. Similar, not exactly the same.
The first time my exhaust header failed I had it rewelded and I thought it looked great. Hundreds of hours later I found it cracked again and sent it to Craig at Vetterman’s for repair. It was quickly returned with reinforcing patches added as part of the repair.

Regards,

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Thanks, Roy! I’ll keep an eye on my repair and send it to Craig if the problem reoccurs.

Found a crack just below the flange-to-tube weld on #3 about 11 years ago and so far, knock on wood, it's holding up fine.